refactor: move logic to application level

src/main/java/io/spring/Util.java

@@ -0,0 +1,7 @@
+package io.spring;
+
+public class Util {
+  public static boolean isEmpty(String value) {
+    return value == null || value.isEmpty();
+  }
+}

src/main/java/io/spring/api/ArticleApi.java

@@ -1,15 +1,17 @@
 package io.spring.api;
 
-import com.fasterxml.jackson.annotation.JsonRootName;
 import io.spring.api.exception.NoAuthorizationException;
 import io.spring.api.exception.ResourceNotFoundException;
-import io.spring.core.service.AuthorizationService;
-import io.spring.application.data.ArticleData;
 import io.spring.application.ArticleQueryService;
+import io.spring.application.article.ArticleCommandService;
+import io.spring.application.article.UpdateArticleParam;
+import io.spring.application.data.ArticleData;
 import io.spring.core.article.ArticleRepository;
+import io.spring.core.service.AuthorizationService;
 import io.spring.core.user.User;
-import lombok.Getter;
+import java.util.HashMap;
-import lombok.NoArgsConstructor;
+import java.util.Map;
+import javax.validation.Valid;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
@@ -21,71 +23,72 @@ import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import javax.validation.Valid;
-import java.util.HashMap;
-import java.util.Map;
-
 @RestController
 @RequestMapping(path = "/articles/{slug}")
 public class ArticleApi {
   private ArticleQueryService articleQueryService;
   private ArticleRepository articleRepository;
+  private ArticleCommandService articleCommandService;
 
   @Autowired
-    public ArticleApi(ArticleQueryService articleQueryService, ArticleRepository articleRepository) {
+  public ArticleApi(
+      ArticleQueryService articleQueryService,
+      ArticleRepository articleRepository,
+      ArticleCommandService articleCommandService) {
     this.articleQueryService = articleQueryService;
     this.articleRepository = articleRepository;
+    this.articleCommandService = articleCommandService;
   }
 
   @GetMapping
-    public ResponseEntity<?> article(@PathVariable("slug") String slug,
+  public ResponseEntity<?> article(
-                                     @AuthenticationPrincipal User user) {
+      @PathVariable("slug") String slug, @AuthenticationPrincipal User user) {
-        return articleQueryService.findBySlug(slug, user)
+    return articleQueryService
+        .findBySlug(slug, user)
         .map(articleData -> ResponseEntity.ok(articleResponse(articleData)))
         .orElseThrow(ResourceNotFoundException::new);
   }
 
   @PutMapping
-    public ResponseEntity<?> updateArticle(@PathVariable("slug") String slug,
+  public ResponseEntity<?> updateArticle(
+      @PathVariable("slug") String slug,
       @AuthenticationPrincipal User user,
       @Valid @RequestBody UpdateArticleParam updateArticleParam) {
-        return articleRepository.findBySlug(slug).map(article -> {
+    return articleRepository
+        .findBySlug(slug)
+        .map(
+            article -> {
               if (!AuthorizationService.canWriteArticle(user, article)) {
                 throw new NoAuthorizationException();
               }
-            article.update(
+              articleCommandService.updateArticle(article, updateArticleParam);
-                updateArticleParam.getTitle(),
+              return ResponseEntity.ok(
-                updateArticleParam.getDescription(),
+                  articleResponse(articleQueryService.findBySlug(slug, user).get()));
-                updateArticleParam.getBody());
+            })
-            articleRepository.save(article);
+        .orElseThrow(ResourceNotFoundException::new);
-            return ResponseEntity.ok(articleResponse(articleQueryService.findBySlug(slug, user).get()));
-        }).orElseThrow(ResourceNotFoundException::new);
   }
 
   @DeleteMapping
-    public ResponseEntity deleteArticle(@PathVariable("slug") String slug,
+  public ResponseEntity deleteArticle(
-                                        @AuthenticationPrincipal User user) {
+      @PathVariable("slug") String slug, @AuthenticationPrincipal User user) {
-        return articleRepository.findBySlug(slug).map(article -> {
+    return articleRepository
+        .findBySlug(slug)
+        .map(
+            article -> {
               if (!AuthorizationService.canWriteArticle(user, article)) {
                 throw new NoAuthorizationException();
               }
               articleRepository.remove(article);
               return ResponseEntity.noContent().build();
-        }).orElseThrow(ResourceNotFoundException::new);
+            })
+        .orElseThrow(ResourceNotFoundException::new);
   }
 
   private Map<String, Object> articleResponse(ArticleData articleData) {
-        return new HashMap<String, Object>() {{
+    return new HashMap<String, Object>() {
+      {
         put("article", articleData);
-        }};
+      }
+    };
   }
 }
-
-@Getter
-@NoArgsConstructor
-@JsonRootName("article")
-class UpdateArticleParam {
-    private String title = "";
-    private String body = "";
-    private String description = "";
-}

src/main/java/io/spring/api/ArticleFavoriteApi.java

@@ -1,13 +1,14 @@
 package io.spring.api;
 
 import io.spring.api.exception.ResourceNotFoundException;
-import io.spring.application.data.ArticleData;
 import io.spring.application.ArticleQueryService;
+import io.spring.application.data.ArticleData;
 import io.spring.core.article.Article;
 import io.spring.core.article.ArticleRepository;
 import io.spring.core.favorite.ArticleFavorite;
 import io.spring.core.favorite.ArticleFavoriteRepository;
 import io.spring.core.user.User;
+import java.util.HashMap;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
@@ -17,8 +18,6 @@ import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import java.util.HashMap;
-
 @RestController
 @RequestMapping(path = "articles/{slug}/favorite")
 public class ArticleFavoriteApi {
@@ -27,7 +26,8 @@ public class ArticleFavoriteApi {
   private ArticleQueryService articleQueryService;
 
   @Autowired
-    public ArticleFavoriteApi(ArticleFavoriteRepository articleFavoriteRepository,
+  public ArticleFavoriteApi(
+      ArticleFavoriteRepository articleFavoriteRepository,
       ArticleRepository articleRepository,
       ArticleQueryService articleQueryService) {
     this.articleFavoriteRepository = articleFavoriteRepository;
@@ -36,32 +36,36 @@ public class ArticleFavoriteApi {
   }
 
   @PostMapping
-    public ResponseEntity favoriteArticle(@PathVariable("slug") String slug,
+  public ResponseEntity favoriteArticle(
-                                          @AuthenticationPrincipal User user) {
+      @PathVariable("slug") String slug, @AuthenticationPrincipal User user) {
-        Article article = getArticle(slug);
+    Article article =
+        articleRepository.findBySlug(slug).orElseThrow(ResourceNotFoundException::new);
     ArticleFavorite articleFavorite = new ArticleFavorite(article.getId(), user.getId());
     articleFavoriteRepository.save(articleFavorite);
     return responseArticleData(articleQueryService.findBySlug(slug, user).get());
   }
 
   @DeleteMapping
-    public ResponseEntity unfavoriteArticle(@PathVariable("slug") String slug,
+  public ResponseEntity unfavoriteArticle(
-                                            @AuthenticationPrincipal User user) {
+      @PathVariable("slug") String slug, @AuthenticationPrincipal User user) {
-        Article article = getArticle(slug);
+    Article article =
-        articleFavoriteRepository.find(article.getId(), user.getId()).ifPresent(favorite -> {
+        articleRepository.findBySlug(slug).orElseThrow(ResourceNotFoundException::new);
+    articleFavoriteRepository
+        .find(article.getId(), user.getId())
+        .ifPresent(
+            favorite -> {
               articleFavoriteRepository.remove(favorite);
             });
     return responseArticleData(articleQueryService.findBySlug(slug, user).get());
   }
 
-    private ResponseEntity<HashMap<String, Object>> responseArticleData(final ArticleData articleData) {
+  private ResponseEntity<HashMap<String, Object>> responseArticleData(
-        return ResponseEntity.ok(new HashMap<String, Object>() {{
+      final ArticleData articleData) {
+    return ResponseEntity.ok(
+        new HashMap<String, Object>() {
+          {
             put("article", articleData);
-        }});
           }
-
+        });
-    private Article getArticle(String slug) {
-        return articleRepository.findBySlug(slug).map(article -> article)
-            .orElseThrow(ResourceNotFoundException::new);
   }
 }

src/main/java/io/spring/api/ArticlesApi.java

@@ -1,25 +1,13 @@
 package io.spring.api;
 
-import com.fasterxml.jackson.annotation.JsonRootName;
 import io.spring.application.ArticleQueryService;
 import io.spring.application.Page;
+import io.spring.application.article.ArticleCommandService;
+import io.spring.application.article.NewArticleParam;
 import io.spring.core.article.Article;
-import io.spring.core.article.ArticleRepository;
 import io.spring.core.user.User;
-import java.lang.annotation.Documented;
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
 import java.util.HashMap;
-import javax.validation.Constraint;
-import javax.validation.ConstraintValidator;
-import javax.validation.ConstraintValidatorContext;
-import javax.validation.Payload;
 import javax.validation.Valid;
-import javax.validation.constraints.NotBlank;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
@@ -33,26 +21,20 @@ import org.springframework.web.bind.annotation.RestController;
 @RestController
 @RequestMapping(path = "/articles")
 public class ArticlesApi {
-  private ArticleRepository articleRepository;
+  private ArticleCommandService articleCommandService;
   private ArticleQueryService articleQueryService;
 
   @Autowired
-  public ArticlesApi(ArticleRepository articleRepository, ArticleQueryService articleQueryService) {
+  public ArticlesApi(
-    this.articleRepository = articleRepository;
+      ArticleCommandService articleCommandService, ArticleQueryService articleQueryService) {
+    this.articleCommandService = articleCommandService;
     this.articleQueryService = articleQueryService;
   }
 
   @PostMapping
   public ResponseEntity createArticle(
       @Valid @RequestBody NewArticleParam newArticleParam, @AuthenticationPrincipal User user) {
-    Article article =
+    Article article = articleCommandService.createArticle(newArticleParam, user);
-        new Article(
-            newArticleParam.getTitle(),
-            newArticleParam.getDescription(),
-            newArticleParam.getBody(),
-            newArticleParam.getTagList(),
-            user.getId());
-    articleRepository.save(article);
     return ResponseEntity.ok(
         new HashMap<String, Object>() {
           {
@@ -82,43 +64,3 @@ public class ArticlesApi {
             tag, author, favoritedBy, new Page(offset, limit), user));
   }
 }
-
-@Getter
-@JsonRootName("article")
-@NoArgsConstructor
-class NewArticleParam {
-  @NotBlank(message = "can't be empty")
-  @DuplicatedArticleConstraint
-  private String title;
-
-  @NotBlank(message = "can't be empty")
-  private String description;
-
-  @NotBlank(message = "can't be empty")
-  private String body;
-
-  private String[] tagList;
-}
-
-@Documented
-@Constraint(validatedBy = DuplicatedArticleValidator.class)
-@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER, ElementType.TYPE_USE})
-@Retention(RetentionPolicy.RUNTIME)
-@interface DuplicatedArticleConstraint {
-  String message() default "article name exists";
-
-  Class<?>[] groups() default {};
-
-  Class<? extends Payload>[] payload() default {};
-}
-
-class DuplicatedArticleValidator
-    implements ConstraintValidator<DuplicatedArticleConstraint, String> {
-
-  @Autowired private ArticleQueryService articleQueryService;
-
-  @Override
-  public boolean isValid(String value, ConstraintValidatorContext context) {
-    return !articleQueryService.findBySlug(Article.toSlug(value), null).isPresent();
-  }
-}

src/main/java/io/spring/api/CommentsApi.java

@@ -51,7 +51,8 @@ public class CommentsApi {
       @PathVariable("slug") String slug,
       @AuthenticationPrincipal User user,
       @Valid @RequestBody NewCommentParam newCommentParam) {
-    Article article = findArticle(slug);
+    Article article =
+        articleRepository.findBySlug(slug).orElseThrow(ResourceNotFoundException::new);
     Comment comment = new Comment(newCommentParam.getBody(), user.getId(), article.getId());
     commentRepository.save(comment);
     return ResponseEntity.status(201)
@@ -61,7 +62,8 @@ public class CommentsApi {
   @GetMapping
   public ResponseEntity getComments(
       @PathVariable("slug") String slug, @AuthenticationPrincipal User user) {
-    Article article = findArticle(slug);
+    Article article =
+        articleRepository.findBySlug(slug).orElseThrow(ResourceNotFoundException::new);
     List<CommentData> comments = commentQueryService.findByArticleId(article.getId(), user);
     return ResponseEntity.ok(
         new HashMap<String, Object>() {
@@ -76,7 +78,8 @@ public class CommentsApi {
       @PathVariable("slug") String slug,
       @PathVariable("id") String commentId,
       @AuthenticationPrincipal User user) {
-    Article article = findArticle(slug);
+    Article article =
+        articleRepository.findBySlug(slug).orElseThrow(ResourceNotFoundException::new);
     return commentRepository
         .findById(article.getId(), commentId)
         .map(
@@ -90,13 +93,6 @@ public class CommentsApi {
         .orElseThrow(ResourceNotFoundException::new);
   }
 
-  private Article findArticle(String slug) {
-    return articleRepository
-        .findBySlug(slug)
-        .map(article -> article)
-        .orElseThrow(ResourceNotFoundException::new);
-  }
-
   private Map<String, Object> commentResponse(CommentData commentData) {
     return new HashMap<String, Object>() {
       {

src/main/java/io/spring/api/CurrentUserApi.java

@@ -1,28 +1,18 @@
 package io.spring.api;
 
-import com.fasterxml.jackson.annotation.JsonRootName;
 import io.spring.application.UserQueryService;
 import io.spring.application.data.UserData;
 import io.spring.application.data.UserWithToken;
+import io.spring.application.user.UpdateUserCommand;
+import io.spring.application.user.UpdateUserParam;
+import io.spring.application.user.UserService;
 import io.spring.core.user.User;
-import io.spring.core.user.UserRepository;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
 import java.util.HashMap;
 import java.util.Map;
-import javax.validation.Constraint;
-import javax.validation.ConstraintValidator;
-import javax.validation.ConstraintValidatorContext;
 import javax.validation.Valid;
-import javax.validation.constraints.Email;
-import lombok.AllArgsConstructor;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
-import org.springframework.stereotype.Service;
-import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PutMapping;
 import org.springframework.web.bind.annotation.RequestBody;
@@ -71,99 +61,3 @@ public class CurrentUserApi {
     };
   }
 }
-
-@Validated
-@Service
-class UserService {
-
-  private UserRepository userRepository;
-
-  @Autowired
-  public UserService(UserRepository userRepository) {
-    this.userRepository = userRepository;
-  }
-
-  public void updateUser(@Valid UpdateUserCommand command) {
-    User user = command.getTargetUser();
-    UpdateUserParam updateUserParam = command.getParam();
-    user.update(
-        updateUserParam.getEmail(),
-        updateUserParam.getUsername(),
-        updateUserParam.getPassword(),
-        updateUserParam.getBio(),
-        updateUserParam.getImage());
-    userRepository.save(user);
-  }
-}
-
-@Getter
-@AllArgsConstructor
-@UpdateUserConstraint
-class UpdateUserCommand {
-
-  private User targetUser;
-  private UpdateUserParam param;
-}
-
-@Constraint(validatedBy = UpdateUserValidator.class)
-@Retention(RetentionPolicy.RUNTIME)
-@interface UpdateUserConstraint {
-
-  String message() default "invalid update param";
-
-  Class[] groups() default {};
-
-  Class[] payload() default {};
-}
-
-class UpdateUserValidator implements ConstraintValidator<UpdateUserConstraint, UpdateUserCommand> {
-
-  @Autowired private UserRepository userRepository;
-
-  @Override
-  public boolean isValid(UpdateUserCommand value, ConstraintValidatorContext context) {
-    String inputEmail = value.getParam().getEmail();
-    String inputUsername = value.getParam().getUsername();
-    final User targetUser = value.getTargetUser();
-
-    boolean isEmailValid =
-        userRepository.findByEmail(inputEmail).map(user -> user.equals(targetUser)).orElse(true);
-    boolean isUsernameValid =
-        userRepository
-            .findByUsername(inputUsername)
-            .map(user -> user.equals(targetUser))
-            .orElse(true);
-    if (isEmailValid && isUsernameValid) {
-      return true;
-    } else {
-      context.disableDefaultConstraintViolation();
-      if (!isEmailValid) {
-        context
-            .buildConstraintViolationWithTemplate("email already exist")
-            .addPropertyNode("email")
-            .addConstraintViolation();
-      }
-      if (!isUsernameValid) {
-        context
-            .buildConstraintViolationWithTemplate("username already exist")
-            .addPropertyNode("username")
-            .addConstraintViolation();
-      }
-      return false;
-    }
-  }
-}
-
-@Getter
-@JsonRootName("user")
-@NoArgsConstructor
-class UpdateUserParam {
-
-  @Email(message = "should be an email")
-  private String email = "";
-
-  private String password = "";
-  private String username = "";
-  private String bio = "";
-  private String image = "";
-}

src/main/java/io/spring/api/UsersApi.java

@@ -7,26 +7,21 @@ import io.spring.api.exception.InvalidAuthenticationException;
 import io.spring.application.UserQueryService;
 import io.spring.application.data.UserData;
 import io.spring.application.data.UserWithToken;
+import io.spring.application.user.RegisterParam;
+import io.spring.application.user.UserService;
 import io.spring.core.service.JwtService;
 import io.spring.core.user.EncryptService;
 import io.spring.core.user.User;
 import io.spring.core.user.UserRepository;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
-import javax.validation.Constraint;
-import javax.validation.ConstraintValidator;
-import javax.validation.ConstraintValidatorContext;
-import javax.validation.Payload;
 import javax.validation.Valid;
 import javax.validation.constraints.Email;
 import javax.validation.constraints.NotBlank;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Value;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -36,34 +31,27 @@ import org.springframework.web.bind.annotation.RestController;
 public class UsersApi {
   private UserRepository userRepository;
   private UserQueryService userQueryService;
-  private String defaultImage;
   private EncryptService encryptService;
   private JwtService jwtService;
+  private UserService userService;
 
   @Autowired
   public UsersApi(
       UserRepository userRepository,
       UserQueryService userQueryService,
       EncryptService encryptService,
-      @Value("${image.default}") String defaultImage,
+      JwtService jwtService,
-      JwtService jwtService) {
+      UserService userService) {
     this.userRepository = userRepository;
     this.userQueryService = userQueryService;
     this.encryptService = encryptService;
-    this.defaultImage = defaultImage;
     this.jwtService = jwtService;
+    this.userService = userService;
   }
 
   @RequestMapping(path = "/users", method = POST)
   public ResponseEntity createUser(@Valid @RequestBody RegisterParam registerParam) {
-    User user =
+    User user = userService.createUser(registerParam);
-        new User(
-            registerParam.getEmail(),
-            registerParam.getUsername(),
-            encryptService.encrypt(registerParam.getPassword()),
-            "",
-            defaultImage);
-    userRepository.save(user);
     UserData userData = userQueryService.findById(user.getId()).get();
     return ResponseEntity.status(201)
         .body(userResponse(new UserWithToken(userData, jwtService.toToken(user))));
@@ -91,47 +79,6 @@ public class UsersApi {
   }
 }
 
-@Constraint(validatedBy = DuplicatedEmailValidator.class)
-@Retention(RetentionPolicy.RUNTIME)
-@interface DuplicatedEmailConstraint {
-  String message() default "duplicated email";
-
-  Class<?>[] groups() default {};
-
-  Class<? extends Payload>[] payload() default {};
-}
-
-class DuplicatedEmailValidator implements ConstraintValidator<DuplicatedEmailConstraint, String> {
-
-  @Autowired private UserRepository userRepository;
-
-  @Override
-  public boolean isValid(String value, ConstraintValidatorContext context) {
-    return (value == null || value.isEmpty()) || !userRepository.findByEmail(value).isPresent();
-  }
-}
-
-@Constraint(validatedBy = DuplicatedUsernameValidator.class)
-@Retention(RetentionPolicy.RUNTIME)
-@interface DuplicatedUsernameConstraint {
-  String message() default "duplicated username";
-
-  Class<?>[] groups() default {};
-
-  Class<? extends Payload>[] payload() default {};
-}
-
-class DuplicatedUsernameValidator
-    implements ConstraintValidator<DuplicatedUsernameConstraint, String> {
-
-  @Autowired private UserRepository userRepository;
-
-  @Override
-  public boolean isValid(String value, ConstraintValidatorContext context) {
-    return (value == null || value.isEmpty()) || !userRepository.findByUsername(value).isPresent();
-  }
-}
-
 @Getter
 @JsonRootName("user")
 @NoArgsConstructor
@@ -143,20 +90,3 @@ class LoginParam {
   @NotBlank(message = "can't be empty")
   private String password;
 }
-
-@Getter
-@JsonRootName("user")
-@NoArgsConstructor
-class RegisterParam {
-  @NotBlank(message = "can't be empty")
-  @Email(message = "should be an email")
-  @DuplicatedEmailConstraint
-  private String email;
-
-  @NotBlank(message = "can't be empty")
-  @DuplicatedUsernameConstraint
-  private String username;
-
-  @NotBlank(message = "can't be empty")
-  private String password;
-}

src/main/java/io/spring/api/security/CORSConfig.java

@@ -1,14 +0,0 @@
-package io.spring.api.security;
-
-import org.springframework.context.annotation.Configuration;
-import org.springframework.web.servlet.config.annotation.CorsRegistry;
-import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
-
-@Configuration
-public class CORSConfig implements WebMvcConfigurer {
-    @Override
-    public void addCorsMappings(CorsRegistry registry) {
-        registry.addMapping("/**")
-            .allowedMethods("HEAD", "GET", "PUT", "POST", "DELETE", "PATCH");
-    }
-}

src/main/java/io/spring/api/security/WebSecurityConfig.java

@@ -1,5 +1,7 @@
 package io.spring.api.security;
 
+import static java.util.Arrays.asList;
+
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -15,8 +17,6 @@ import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.cors.CorsConfigurationSource;
 import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
 
-import static java.util.Arrays.asList;
-
 @Configuration
 @EnableWebSecurity
 public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
@@ -32,11 +32,12 @@ public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
     @Override
     protected void configure(HttpSecurity http) throws Exception {
 
-        if (h2ConsoleEnabled)
+        if (h2ConsoleEnabled) {
             http.authorizeRequests()
                 .antMatchers("/h2-console", "/h2-console/**").permitAll()
                 .and()
                 .headers().frameOptions().sameOrigin();
+        }
 
         http.csrf().disable()
             .cors()
@@ -46,6 +47,8 @@ public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
             .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
             .authorizeRequests()
             .antMatchers(HttpMethod.OPTIONS).permitAll()
+            .antMatchers("/graphiql").permitAll()
+            .antMatchers("/graphql").permitAll()
             .antMatchers(HttpMethod.GET, "/articles/feed").authenticated()
             .antMatchers(HttpMethod.POST, "/users", "/users/login").permitAll()
             .antMatchers(HttpMethod.GET, "/articles/**", "/profiles/**", "/tags").permitAll()
@@ -62,7 +65,7 @@ public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
             "GET", "POST", "PUT", "DELETE", "PATCH"));
         // setAllowCredentials(true) is important, otherwise:
         // The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'.
-        configuration.setAllowCredentials(true);
+        configuration.setAllowCredentials(false);
         // setAllowedHeaders is important! Without it, OPTIONS preflight request
         // will fail with 403 Invalid CORS request
         configuration.setAllowedHeaders(asList("Authorization", "Cache-Control", "Content-Type"));

src/main/java/io/spring/application/ProfileQueryService.java

@@ -2,21 +2,21 @@ package io.spring.application;
 
 import io.spring.application.data.ProfileData;
 import io.spring.application.data.UserData;
-import io.spring.infrastructure.mybatis.readservice.UserReadService;
 import io.spring.core.user.User;
+import io.spring.infrastructure.mybatis.readservice.UserReadService;
 import io.spring.infrastructure.mybatis.readservice.UserRelationshipQueryService;
+import java.util.Optional;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
-import java.util.Optional;
-
 @Component
 public class ProfileQueryService {
   private UserReadService userReadService;
   private UserRelationshipQueryService userRelationshipQueryService;
 
   @Autowired
-    public ProfileQueryService(UserReadService userReadService, UserRelationshipQueryService userRelationshipQueryService) {
+  public ProfileQueryService(
+      UserReadService userReadService, UserRelationshipQueryService userRelationshipQueryService) {
     this.userReadService = userReadService;
     this.userRelationshipQueryService = userRelationshipQueryService;
   }
@@ -26,12 +26,15 @@ public class ProfileQueryService {
     if (userData == null) {
       return Optional.empty();
     } else {
-            ProfileData profileData = new ProfileData(
+      ProfileData profileData =
+          new ProfileData(
               userData.getId(),
               userData.getUsername(),
               userData.getBio(),
               userData.getImage(),
-                userRelationshipQueryService.isUserFollowing(currentUser.getId(), userData.getId()));
+              currentUser != null
+                  && userRelationshipQueryService.isUserFollowing(
+                      currentUser.getId(), userData.getId()));
       return Optional.of(profileData);
     }
   }

src/main/java/io/spring/application/article/ArticleCommandService.java

@@ -0,0 +1,42 @@
+package io.spring.application.article;
+
+import io.spring.core.article.Article;
+import io.spring.core.article.ArticleRepository;
+import io.spring.core.user.User;
+import javax.validation.Valid;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.validation.annotation.Validated;
+
+@Service
+@Validated
+public class ArticleCommandService {
+
+  private ArticleRepository articleRepository;
+
+  @Autowired
+  public ArticleCommandService(ArticleRepository articleRepository) {
+    this.articleRepository = articleRepository;
+  }
+
+  public Article createArticle(@Valid NewArticleParam newArticleParam, User creator) {
+    Article article =
+        new Article(
+            newArticleParam.getTitle(),
+            newArticleParam.getDescription(),
+            newArticleParam.getBody(),
+            newArticleParam.getTagList(),
+            creator.getId());
+    articleRepository.save(article);
+    return article;
+  }
+
+  public Article updateArticle(Article article, @Valid UpdateArticleParam updateArticleParam) {
+    article.update(
+        updateArticleParam.getTitle(),
+        updateArticleParam.getDescription(),
+        updateArticleParam.getBody());
+    articleRepository.save(article);
+    return article;
+  }
+}

src/main/java/io/spring/application/article/DuplicatedArticleConstraint.java

@@ -0,0 +1,21 @@
+package io.spring.application.article;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import javax.validation.Constraint;
+import javax.validation.Payload;
+
+@Documented
+@Constraint(validatedBy = DuplicatedArticleValidator.class)
+@Target({ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER, ElementType.TYPE_USE})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface DuplicatedArticleConstraint {
+  String message() default "article name exists";
+
+  Class<?>[] groups() default {};
+
+  Class<? extends Payload>[] payload() default {};
+}

src/main/java/io/spring/application/article/DuplicatedArticleValidator.java

@@ -0,0 +1,18 @@
+package io.spring.application.article;
+
+import io.spring.application.ArticleQueryService;
+import io.spring.core.article.Article;
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import org.springframework.beans.factory.annotation.Autowired;
+
+class DuplicatedArticleValidator
+    implements ConstraintValidator<DuplicatedArticleConstraint, String> {
+
+  @Autowired private ArticleQueryService articleQueryService;
+
+  @Override
+  public boolean isValid(String value, ConstraintValidatorContext context) {
+    return !articleQueryService.findBySlug(Article.toSlug(value), null).isPresent();
+  }
+}

src/main/java/io/spring/application/article/NewArticleParam.java

@@ -0,0 +1,28 @@
+package io.spring.application.article;
+
+import com.fasterxml.jackson.annotation.JsonRootName;
+import java.util.List;
+import javax.validation.constraints.NotBlank;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@JsonRootName("article")
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class NewArticleParam {
+  @NotBlank(message = "can't be empty")
+  @DuplicatedArticleConstraint
+  private String title;
+
+  @NotBlank(message = "can't be empty")
+  private String description;
+
+  @NotBlank(message = "can't be empty")
+  private String body;
+
+  private List<String> tagList;
+}

src/main/java/io/spring/application/article/UpdateArticleParam.java

@@ -0,0 +1,16 @@
+package io.spring.application.article;
+
+import com.fasterxml.jackson.annotation.JsonRootName;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+@AllArgsConstructor
+@JsonRootName("article")
+public class UpdateArticleParam {
+  private String title = "";
+  private String body = "";
+  private String description = "";
+}

src/main/java/io/spring/application/user/DuplicatedEmailConstraint.java

@@ -0,0 +1,16 @@
+package io.spring.application.user;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import javax.validation.Constraint;
+import javax.validation.Payload;
+
+@Constraint(validatedBy = DuplicatedEmailValidator.class)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface DuplicatedEmailConstraint {
+  String message() default "duplicated email";
+
+  Class<?>[] groups() default {};
+
+  Class<? extends Payload>[] payload() default {};
+}

src/main/java/io/spring/application/user/DuplicatedEmailValidator.java

@@ -0,0 +1,17 @@
+package io.spring.application.user;
+
+import io.spring.core.user.UserRepository;
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import org.springframework.beans.factory.annotation.Autowired;
+
+public class DuplicatedEmailValidator
+    implements ConstraintValidator<DuplicatedEmailConstraint, String> {
+
+  @Autowired private UserRepository userRepository;
+
+  @Override
+  public boolean isValid(String value, ConstraintValidatorContext context) {
+    return (value == null || value.isEmpty()) || !userRepository.findByEmail(value).isPresent();
+  }
+}

src/main/java/io/spring/application/user/DuplicatedUsernameConstraint.java

@@ -0,0 +1,16 @@
+package io.spring.application.user;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import javax.validation.Constraint;
+import javax.validation.Payload;
+
+@Constraint(validatedBy = DuplicatedUsernameValidator.class)
+@Retention(RetentionPolicy.RUNTIME)
+@interface DuplicatedUsernameConstraint {
+  String message() default "duplicated username";
+
+  Class<?>[] groups() default {};
+
+  Class<? extends Payload>[] payload() default {};
+}

src/main/java/io/spring/application/user/DuplicatedUsernameValidator.java

@@ -0,0 +1,17 @@
+package io.spring.application.user;
+
+import io.spring.core.user.UserRepository;
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import org.springframework.beans.factory.annotation.Autowired;
+
+class DuplicatedUsernameValidator
+    implements ConstraintValidator<DuplicatedUsernameConstraint, String> {
+
+  @Autowired private UserRepository userRepository;
+
+  @Override
+  public boolean isValid(String value, ConstraintValidatorContext context) {
+    return (value == null || value.isEmpty()) || !userRepository.findByUsername(value).isPresent();
+  }
+}

src/main/java/io/spring/application/user/RegisterParam.java

@@ -0,0 +1,26 @@
+package io.spring.application.user;
+
+import com.fasterxml.jackson.annotation.JsonRootName;
+import javax.validation.constraints.Email;
+import javax.validation.constraints.NotBlank;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@JsonRootName("user")
+@AllArgsConstructor
+@NoArgsConstructor
+public class RegisterParam {
+  @NotBlank(message = "can't be empty")
+  @Email(message = "should be an email")
+  @DuplicatedEmailConstraint
+  private String email;
+
+  @NotBlank(message = "can't be empty")
+  @DuplicatedUsernameConstraint
+  private String username;
+
+  @NotBlank(message = "can't be empty")
+  private String password;
+}

src/main/java/io/spring/application/user/UpdateUserCommand.java

@@ -0,0 +1,14 @@
+package io.spring.application.user;
+
+import io.spring.core.user.User;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+@UpdateUserConstraint
+public class UpdateUserCommand {
+
+  private User targetUser;
+  private UpdateUserParam param;
+}

src/main/java/io/spring/application/user/UpdateUserParam.java

@@ -0,0 +1,25 @@
+package io.spring.application.user;
+
+import com.fasterxml.jackson.annotation.JsonRootName;
+import javax.validation.constraints.Email;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@JsonRootName("user")
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class UpdateUserParam {
+
+  @Builder.Default
+  @Email(message = "should be an email")
+  private String email = "";
+
+  @Builder.Default private String password = "";
+  @Builder.Default private String username = "";
+  @Builder.Default private String bio = "";
+  @Builder.Default private String image = "";
+}

src/main/java/io/spring/application/user/UserService.java

@@ -0,0 +1,106 @@
+package io.spring.application.user;
+
+import io.spring.core.user.EncryptService;
+import io.spring.core.user.User;
+import io.spring.core.user.UserRepository;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import javax.validation.Constraint;
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+import javax.validation.Valid;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+import org.springframework.validation.annotation.Validated;
+
+@Service
+@Validated
+public class UserService {
+  private UserRepository userRepository;
+  private String defaultImage;
+  private EncryptService encryptService;
+
+  @Autowired
+  public UserService(
+      UserRepository userRepository,
+      @Value("${image.default}") String defaultImage,
+      EncryptService encryptService) {
+    this.userRepository = userRepository;
+    this.defaultImage = defaultImage;
+    this.encryptService = encryptService;
+  }
+
+  public User createUser(@Valid RegisterParam registerParam) {
+    User user =
+        new User(
+            registerParam.getEmail(),
+            registerParam.getUsername(),
+            encryptService.encrypt(registerParam.getPassword()),
+            "",
+            defaultImage);
+    userRepository.save(user);
+    return user;
+  }
+
+  public void updateUser(@Valid UpdateUserCommand command) {
+    User user = command.getTargetUser();
+    UpdateUserParam updateUserParam = command.getParam();
+    user.update(
+        updateUserParam.getEmail(),
+        updateUserParam.getUsername(),
+        updateUserParam.getPassword(),
+        updateUserParam.getBio(),
+        updateUserParam.getImage());
+    userRepository.save(user);
+  }
+}
+
+@Constraint(validatedBy = UpdateUserValidator.class)
+@Retention(RetentionPolicy.RUNTIME)
+@interface UpdateUserConstraint {
+
+  String message() default "invalid update param";
+
+  Class[] groups() default {};
+
+  Class[] payload() default {};
+}
+
+class UpdateUserValidator implements ConstraintValidator<UpdateUserConstraint, UpdateUserCommand> {
+
+  @Autowired private UserRepository userRepository;
+
+  @Override
+  public boolean isValid(UpdateUserCommand value, ConstraintValidatorContext context) {
+    String inputEmail = value.getParam().getEmail();
+    String inputUsername = value.getParam().getUsername();
+    final User targetUser = value.getTargetUser();
+
+    boolean isEmailValid =
+        userRepository.findByEmail(inputEmail).map(user -> user.equals(targetUser)).orElse(true);
+    boolean isUsernameValid =
+        userRepository
+            .findByUsername(inputUsername)
+            .map(user -> user.equals(targetUser))
+            .orElse(true);
+    if (isEmailValid && isUsernameValid) {
+      return true;
+    } else {
+      context.disableDefaultConstraintViolation();
+      if (!isEmailValid) {
+        context
+            .buildConstraintViolationWithTemplate("email already exist")
+            .addPropertyNode("email")
+            .addConstraintViolation();
+      }
+      if (!isUsernameValid) {
+        context
+            .buildConstraintViolationWithTemplate("username already exist")
+            .addPropertyNode("username")
+            .addConstraintViolation();
+      }
+      return false;
+    }
+  }
+}

src/main/java/io/spring/core/article/Article.java

@@ -1,17 +1,16 @@
 package io.spring.core.article;
 
+import static java.util.stream.Collectors.toList;
+
+import io.spring.Util;
+import java.util.HashSet;
+import java.util.List;
+import java.util.UUID;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import org.joda.time.DateTime;
 
-import java.util.Arrays;
-import java.util.List;
-import java.util.UUID;
-
-import static java.util.stream.Collectors.toList;
-import static java.util.stream.Collectors.toSet;
-
 @Getter
 @NoArgsConstructor
 @EqualsAndHashCode(of = {"id"})
@@ -26,35 +25,44 @@ public class Article {
   private DateTime createdAt;
   private DateTime updatedAt;
 
-    public Article(String title, String description, String body, String[] tagList, String userId) {
+  public Article(
+      String title, String description, String body, List<String> tagList, String userId) {
     this(title, description, body, tagList, userId, new DateTime());
   }
 
-    public Article(String title, String description, String body, String[] tagList, String userId, DateTime createdAt) {
+  public Article(
+      String title,
+      String description,
+      String body,
+      List<String> tagList,
+      String userId,
+      DateTime createdAt) {
     this.id = UUID.randomUUID().toString();
     this.slug = toSlug(title);
     this.title = title;
     this.description = description;
     this.body = body;
-        this.tags = Arrays.stream(tagList).collect(toSet()).stream().map(Tag::new).collect(toList());
+    this.tags = new HashSet<>(tagList).stream().map(Tag::new).collect(toList());
     this.userId = userId;
     this.createdAt = createdAt;
     this.updatedAt = createdAt;
   }
 
   public void update(String title, String description, String body) {
-        if (!"".equals(title)) {
+    if (!Util.isEmpty(title)) {
       this.title = title;
       this.slug = toSlug(title);
-        }
-        if (!"".equals(description)) {
-            this.description = description;
-        }
-        if (!"".equals(body)) {
-            this.body = body;
-        }
       this.updatedAt = new DateTime();
     }
+    if (!Util.isEmpty(description)) {
+      this.description = description;
+      this.updatedAt = new DateTime();
+    }
+    if (!Util.isEmpty(body)) {
+      this.body = body;
+      this.updatedAt = new DateTime();
+    }
+  }
 
   public static String toSlug(String title) {
     return title.toLowerCase().replaceAll("[\\&|[\\uFE30-\\uFFA0]|\\’|\\”|\\s\\?\\,\\.]+", "-");

src/main/java/io/spring/core/user/User.java

@@ -1,11 +1,11 @@
 package io.spring.core.user;
 
+import io.spring.Util;
+import java.util.UUID;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 
-import java.util.UUID;
-
 @Getter
 @NoArgsConstructor
 @EqualsAndHashCode(of = {"id"})
@@ -27,23 +27,23 @@ public class User {
   }
 
   public void update(String email, String username, String password, String bio, String image) {
-        if (!"".equals(email)) {
+    if (!Util.isEmpty(email)) {
       this.email = email;
     }
 
-        if (!"".equals(username)) {
+    if (!Util.isEmpty(username)) {
       this.username = username;
     }
 
-        if (!"".equals(password)) {
+    if (!Util.isEmpty(password)) {
       this.password = password;
     }
 
-        if (!"".equals(bio)) {
+    if (!Util.isEmpty(bio)) {
       this.bio = bio;
     }
 
-        if (!"".equals(image)) {
+    if (!Util.isEmpty(image)) {
       this.image = image;
     }
   }

src/main/resources/mapper/CommentReadService.xml

@@ -6,6 +6,7 @@
         C.id commentId,
         C.body commentBody,
         C.created_at commentCreatedAt,
+        C.article_id commentArticleId,
         <include refid="io.spring.infrastructure.mybatis.readservice.ArticleReadService.profileColumns"/>
         from comments C
         left join users U

src/main/resources/mapper/TransferData.xml

@@ -34,6 +34,7 @@
         <result column="commentBody" property="body"/>
         <result column="commentCreatedAt" property="createdAt"/>
         <result column="commentCreatedAt" property="updatedAt"/>
+        <result column="commentArticleId" property="articleId"/>
         <association property="profileData" resultMap="profileData"/>
     </resultMap>
 </mapper>

src/test/java/io/spring/api/ArticleApiTest.java

@@ -1,15 +1,28 @@
 package io.spring.api;
 
+import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
 import io.restassured.module.mockmvc.RestAssuredMockMvc;
 import io.spring.JacksonCustomizations;
 import io.spring.TestHelper;
 import io.spring.api.security.WebSecurityConfig;
 import io.spring.application.ArticleQueryService;
+import io.spring.application.article.ArticleCommandService;
 import io.spring.application.data.ArticleData;
 import io.spring.application.data.ProfileData;
 import io.spring.core.article.Article;
 import io.spring.core.article.ArticleRepository;
 import io.spring.core.user.User;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
 import org.joda.time.DateTime;
 import org.joda.time.format.ISODateTimeFormat;
 import org.junit.Before;
@@ -20,30 +33,16 @@ import org.springframework.boot.test.mock.mockito.MockBean;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.web.servlet.MockMvc;
 
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
-
-import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
-import static org.hamcrest.core.IsEqual.equalTo;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyString;
-import static org.mockito.ArgumentMatchers.eq;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
-
 @WebMvcTest({ArticleApi.class})
 @Import({WebSecurityConfig.class, JacksonCustomizations.class})
 public class ArticleApiTest extends TestWithCurrentUser {
-    @Autowired
+  @Autowired private MockMvc mvc;
-    private MockMvc mvc;
 
-    @MockBean
+  @MockBean private ArticleQueryService articleQueryService;
-    private ArticleQueryService articleQueryService;
 
-    @MockBean
+  @MockBean private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
+
+  @MockBean ArticleCommandService articleCommandService;
 
   @Override
   @Before
@@ -56,7 +55,14 @@ public class ArticleApiTest extends TestWithCurrentUser {
   public void should_read_article_success() throws Exception {
     String slug = "test-new-article";
     DateTime time = new DateTime();
-        Article article = new Article("Test New Article", "Desc", "Body", new String[]{"java", "spring", "jpg"}, user.getId(), time);
+    Article article =
+        new Article(
+            "Test New Article",
+            "Desc",
+            "Body",
+            Arrays.asList("java", "spring", "jpg"),
+            user.getId(),
+            time);
     ArticleData articleData = TestHelper.getArticleDataFromArticleAndUser(article, user);
 
     when(articleQueryService.findBySlug(eq(slug), eq(null))).thenReturn(Optional.of(articleData));
@@ -68,16 +74,12 @@ public class ArticleApiTest extends TestWithCurrentUser {
         .body("article.slug", equalTo(slug))
         .body("article.body", equalTo(articleData.getBody()))
         .body("article.createdAt", equalTo(ISODateTimeFormat.dateTime().withZoneUTC().print(time)));
-
   }
 
   @Test
   public void should_404_if_article_not_found() throws Exception {
     when(articleQueryService.findBySlug(anyString(), any())).thenReturn(Optional.empty());
-        RestAssuredMockMvc.when()
+    RestAssuredMockMvc.when().get("/articles/not-exists").then().statusCode(404);
-            .get("/articles/not-exists")
-            .then()
-            .statusCode(404);
   }
 
   @Test
@@ -87,12 +89,14 @@ public class ArticleApiTest extends TestWithCurrentUser {
     String description = "new description";
     Map<String, Object> updateParam = prepareUpdateParam(title, body, description);
 
-        Article article = new Article(title, description, body, new String[]{"java", "spring", "jpg"}, user.getId());
+    Article article =
+        new Article(title, description, body, Arrays.asList("java", "spring", "jpg"), user.getId());
 
     ArticleData articleData = TestHelper.getArticleDataFromArticleAndUser(article, user);
 
     when(articleRepository.findBySlug(eq(article.getSlug()))).thenReturn(Optional.of(article));
-        when(articleQueryService.findBySlug(eq(article.getSlug()), eq(user))).thenReturn(Optional.of(articleData));
+    when(articleQueryService.findBySlug(eq(article.getSlug()), eq(user)))
+        .thenReturn(Optional.of(articleData));
 
     given()
         .contentType("application/json")
@@ -114,10 +118,13 @@ public class ArticleApiTest extends TestWithCurrentUser {
 
     User anotherUser = new User("test@test.com", "test", "123123", "", "");
 
-        Article article = new Article(title, description, body, new String[]{"java", "spring", "jpg"}, anotherUser.getId());
+    Article article =
+        new Article(
+            title, description, body, Arrays.asList("java", "spring", "jpg"), anotherUser.getId());
 
     DateTime time = new DateTime();
-        ArticleData articleData = new ArticleData(
+    ArticleData articleData =
+        new ArticleData(
             article.getId(),
             article.getSlug(),
             article.getTitle(),
@@ -128,10 +135,16 @@ public class ArticleApiTest extends TestWithCurrentUser {
             time,
             time,
             Arrays.asList("joda"),
-            new ProfileData(anotherUser.getId(), anotherUser.getUsername(), anotherUser.getBio(), anotherUser.getImage(), false));
+            new ProfileData(
+                anotherUser.getId(),
+                anotherUser.getUsername(),
+                anotherUser.getBio(),
+                anotherUser.getImage(),
+                false));
 
     when(articleRepository.findBySlug(eq(article.getSlug()))).thenReturn(Optional.of(article));
-        when(articleQueryService.findBySlug(eq(article.getSlug()), eq(user))).thenReturn(Optional.of(articleData));
+    when(articleQueryService.findBySlug(eq(article.getSlug()), eq(user)))
+        .thenReturn(Optional.of(articleData));
 
     given()
         .contentType("application/json")
@@ -149,7 +162,8 @@ public class ArticleApiTest extends TestWithCurrentUser {
     String body = "body";
     String description = "description";
 
-        Article article = new Article(title, description, body, new String[]{"java", "spring", "jpg"}, user.getId());
+    Article article =
+        new Article(title, description, body, Arrays.asList("java", "spring", "jpg"), user.getId());
     when(articleRepository.findBySlug(eq(article.getSlug()))).thenReturn(Optional.of(article));
 
     given()
@@ -170,7 +184,9 @@ public class ArticleApiTest extends TestWithCurrentUser {
 
     User anotherUser = new User("test@test.com", "test", "123123", "", "");
 
-        Article article = new Article(title, description, body, new String[]{"java", "spring", "jpg"}, anotherUser.getId());
+    Article article =
+        new Article(
+            title, description, body, Arrays.asList("java", "spring", "jpg"), anotherUser.getId());
 
     when(articleRepository.findBySlug(eq(article.getSlug()))).thenReturn(Optional.of(article));
     given()
@@ -181,13 +197,20 @@ public class ArticleApiTest extends TestWithCurrentUser {
         .statusCode(403);
   }
 
-    private HashMap<String, Object> prepareUpdateParam(final String title, final String body, final String description) {
+  private HashMap<String, Object> prepareUpdateParam(
-        return new HashMap<String, Object>() {{
+      final String title, final String body, final String description) {
-            put("article", new HashMap<String, Object>() {{
+    return new HashMap<String, Object>() {
+      {
+        put(
+            "article",
+            new HashMap<String, Object>() {
+              {
                 put("title", title);
                 put("body", body);
                 put("description", description);
-            }});
+              }
-        }};
+            });
+      }
+    };
   }
 }

src/test/java/io/spring/api/ArticleFavoriteApiTest.java

@@ -1,5 +1,12 @@
 package io.spring.api;
 
+import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
 import io.restassured.module.mockmvc.RestAssuredMockMvc;
 import io.spring.JacksonCustomizations;
 import io.spring.api.security.WebSecurityConfig;
@@ -12,6 +19,9 @@ import io.spring.core.article.Tag;
 import io.spring.core.favorite.ArticleFavorite;
 import io.spring.core.favorite.ArticleFavoriteRepository;
 import io.spring.core.user.User;
+import java.util.Arrays;
+import java.util.Optional;
+import java.util.stream.Collectors;
 import org.junit.Before;
 import org.junit.Test;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -20,30 +30,16 @@ import org.springframework.boot.test.mock.mockito.MockBean;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.web.servlet.MockMvc;
 
-import java.util.Optional;
-import java.util.stream.Collectors;
-
-import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
-import static org.hamcrest.core.IsEqual.equalTo;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.eq;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
-
 @WebMvcTest(ArticleFavoriteApi.class)
 @Import({WebSecurityConfig.class, JacksonCustomizations.class})
 public class ArticleFavoriteApiTest extends TestWithCurrentUser {
-    @Autowired
+  @Autowired private MockMvc mvc;
-    private MockMvc mvc;
 
-    @MockBean
+  @MockBean private ArticleFavoriteRepository articleFavoriteRepository;
-    private ArticleFavoriteRepository articleFavoriteRepository;
 
-    @MockBean
+  @MockBean private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
-    @MockBean
+  @MockBean private ArticleQueryService articleQueryService;
-    private ArticleQueryService articleQueryService;
 
   private Article article;
 
@@ -52,9 +48,10 @@ public class ArticleFavoriteApiTest extends TestWithCurrentUser {
     super.setUp();
     RestAssuredMockMvc.mockMvc(mvc);
     User anotherUser = new User("other@test.com", "other", "123", "", "");
-        article = new Article("title", "desc", "body", new String[]{"java"}, anotherUser.getId());
+    article = new Article("title", "desc", "body", Arrays.asList("java"), anotherUser.getId());
     when(articleRepository.findBySlug(eq(article.getSlug()))).thenReturn(Optional.of(article));
-        ArticleData articleData = new ArticleData(
+    ArticleData articleData =
+        new ArticleData(
             article.getId(),
             article.getSlug(),
             article.getTitle(),
@@ -70,9 +67,9 @@ public class ArticleFavoriteApiTest extends TestWithCurrentUser {
                 anotherUser.getUsername(),
                 anotherUser.getBio(),
                 anotherUser.getImage(),
-                false
+                false));
-            ));
+    when(articleQueryService.findBySlug(eq(articleData.getSlug()), eq(user)))
-        when(articleQueryService.findBySlug(eq(articleData.getSlug()), eq(user))).thenReturn(Optional.of(articleData));
+        .thenReturn(Optional.of(articleData));
   }
 
   @Test
@@ -91,7 +88,8 @@ public class ArticleFavoriteApiTest extends TestWithCurrentUser {
 
   @Test
   public void should_unfavorite_an_article_success() throws Exception {
-        when(articleFavoriteRepository.find(eq(article.getId()), eq(user.getId()))).thenReturn(Optional.of(new ArticleFavorite(article.getId(), user.getId())));
+    when(articleFavoriteRepository.find(eq(article.getId()), eq(user.getId())))
+        .thenReturn(Optional.of(new ArticleFavorite(article.getId(), user.getId())));
     given()
         .header("Authorization", "Token " + token)
         .when()

src/test/java/io/spring/api/ArticlesApiTest.java

@@ -1,6 +1,7 @@
 package io.spring.api;
 
 import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
+import static java.util.Arrays.asList;
 import static org.hamcrest.core.IsEqual.equalTo;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
@@ -11,12 +12,12 @@ import io.restassured.module.mockmvc.RestAssuredMockMvc;
 import io.spring.JacksonCustomizations;
 import io.spring.api.security.WebSecurityConfig;
 import io.spring.application.ArticleQueryService;
+import io.spring.application.article.ArticleCommandService;
 import io.spring.application.data.ArticleData;
 import io.spring.application.data.ProfileData;
 import io.spring.core.article.Article;
-import io.spring.core.article.ArticleRepository;
-import java.util.Arrays;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import org.joda.time.DateTime;
@@ -33,10 +34,10 @@ import org.springframework.test.web.servlet.MockMvc;
 public class ArticlesApiTest extends TestWithCurrentUser {
   @Autowired private MockMvc mvc;
 
-  @MockBean private ArticleRepository articleRepository;
-
   @MockBean private ArticleQueryService articleQueryService;
 
+  @MockBean private ArticleCommandService articleCommandService;
+
   @Override
   @Before
   public void setUp() throws Exception {
@@ -50,7 +51,7 @@ public class ArticlesApiTest extends TestWithCurrentUser {
     String slug = "how-to-train-your-dragon";
     String description = "Ever wonder how?";
     String body = "You have to believe";
-    String[] tagList = {"reactjs", "angularjs", "dragons"};
+    List<String> tagList = asList("reactjs", "angularjs", "dragons");
     Map<String, Object> param = prepareParam(title, description, body, tagList);
 
     ArticleData articleData =
@@ -64,9 +65,12 @@ public class ArticlesApiTest extends TestWithCurrentUser {
             0,
             new DateTime(),
             new DateTime(),
-            Arrays.asList(tagList),
+            tagList,
             new ProfileData("userid", user.getUsername(), user.getBio(), user.getImage(), false));
 
+    when(articleCommandService.createArticle(any(), any()))
+        .thenReturn(new Article(title, description, body, tagList, user.getId()));
+
     when(articleQueryService.findBySlug(eq(Article.toSlug(title)), any()))
         .thenReturn(Optional.empty());
 
@@ -87,7 +91,7 @@ public class ArticlesApiTest extends TestWithCurrentUser {
         .body("article.author.username", equalTo(user.getUsername()))
         .body("article.author.id", equalTo(null));
 
-    verify(articleRepository).save(any());
+    verify(articleCommandService).createArticle(any(), any());
   }
 
   @Test
@@ -96,7 +100,7 @@ public class ArticlesApiTest extends TestWithCurrentUser {
     String description = "Ever wonder how?";
     String body = "";
     String[] tagList = {"reactjs", "angularjs", "dragons"};
-    Map<String, Object> param = prepareParam(title, description, body, tagList);
+    Map<String, Object> param = prepareParam(title, description, body, asList(tagList));
 
     given()
         .contentType("application/json")
@@ -117,7 +121,7 @@ public class ArticlesApiTest extends TestWithCurrentUser {
     String description = "Ever wonder how?";
     String body = "You have to believe";
     String[] tagList = {"reactjs", "angularjs", "dragons"};
-    Map<String, Object> param = prepareParam(title, description, body, tagList);
+    Map<String, Object> param = prepareParam(title, description, body, asList(tagList));
 
     ArticleData articleData =
         new ArticleData(
@@ -130,7 +134,7 @@ public class ArticlesApiTest extends TestWithCurrentUser {
             0,
             new DateTime(),
             new DateTime(),
-            Arrays.asList(tagList),
+            asList(tagList),
             new ProfileData("userid", user.getUsername(), user.getBio(), user.getImage(), false));
 
     when(articleQueryService.findBySlug(eq(Article.toSlug(title)), any()))
@@ -150,7 +154,7 @@ public class ArticlesApiTest extends TestWithCurrentUser {
   }
 
   private HashMap<String, Object> prepareParam(
-      final String title, final String description, final String body, final String[] tagList) {
+      final String title, final String description, final String body, final List<String> tagList) {
     return new HashMap<String, Object>() {
       {
         put(

src/test/java/io/spring/api/CommentsApiTest.java

@@ -1,5 +1,12 @@
 package io.spring.api;
 
+import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.when;
+
 import io.restassured.module.mockmvc.RestAssuredMockMvc;
 import io.spring.JacksonCustomizations;
 import io.spring.api.security.WebSecurityConfig;
@@ -11,6 +18,10 @@ import io.spring.core.article.ArticleRepository;
 import io.spring.core.comment.Comment;
 import io.spring.core.comment.CommentRepository;
 import io.spring.core.user.User;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
 import org.junit.Before;
 import org.junit.Test;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -19,59 +30,52 @@ import org.springframework.boot.test.mock.mockito.MockBean;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.web.servlet.MockMvc;
 
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
-
-import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
-import static org.hamcrest.core.IsEqual.equalTo;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyString;
-import static org.mockito.ArgumentMatchers.eq;
-import static org.mockito.Mockito.when;
-
 @WebMvcTest(CommentsApi.class)
 @Import({WebSecurityConfig.class, JacksonCustomizations.class})
 public class CommentsApiTest extends TestWithCurrentUser {
 
-    @MockBean
+  @MockBean private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
-    @MockBean
+  @MockBean private CommentRepository commentRepository;
-    private CommentRepository commentRepository;
+  @MockBean private CommentQueryService commentQueryService;
-    @MockBean
-    private CommentQueryService commentQueryService;
 
   private Article article;
   private CommentData commentData;
   private Comment comment;
-    @Autowired
+  @Autowired private MockMvc mvc;
-    private MockMvc mvc;
 
   @Before
   public void setUp() throws Exception {
     RestAssuredMockMvc.mockMvc(mvc);
     super.setUp();
-        article = new Article("title", "desc", "body", new String[]{"test", "java"}, user.getId());
+    article = new Article("title", "desc", "body", Arrays.asList("test", "java"), user.getId());
     when(articleRepository.findBySlug(eq(article.getSlug()))).thenReturn(Optional.of(article));
     comment = new Comment("comment", user.getId(), article.getId());
-        commentData = new CommentData(
+    commentData =
+        new CommentData(
             comment.getId(),
             comment.getBody(),
             comment.getArticleId(),
             comment.getCreatedAt(),
             comment.getCreatedAt(),
-            new ProfileData(user.getId(), user.getUsername(), user.getBio(), user.getImage(), false));
+            new ProfileData(
+                user.getId(), user.getUsername(), user.getBio(), user.getImage(), false));
   }
 
   @Test
   public void should_create_comment_success() throws Exception {
-        Map<String, Object> param = new HashMap<String, Object>() {{
+    Map<String, Object> param =
-            put("comment", new HashMap<String, Object>() {{
+        new HashMap<String, Object>() {
+          {
+            put(
+                "comment",
+                new HashMap<String, Object>() {
+                  {
                     put("body", "comment content");
-            }});
+                  }
-        }};
+                });
+          }
+        };
 
     when(commentQueryService.findById(anyString(), eq(user))).thenReturn(Optional.of(commentData));
 
@@ -88,11 +92,18 @@ public class CommentsApiTest extends TestWithCurrentUser {
 
   @Test
   public void should_get_422_with_empty_body() throws Exception {
-        Map<String, Object> param = new HashMap<String, Object>() {{
+    Map<String, Object> param =
-            put("comment", new HashMap<String, Object>() {{
+        new HashMap<String, Object>() {
+          {
+            put(
+                "comment",
+                new HashMap<String, Object>() {
+                  {
                     put("body", "");
-            }});
+                  }
-        }};
+                });
+          }
+        };
 
     given()
         .contentType("application/json")
@@ -103,12 +114,12 @@ public class CommentsApiTest extends TestWithCurrentUser {
         .then()
         .statusCode(422)
         .body("errors.body[0]", equalTo("can't be empty"));
-
   }
 
   @Test
   public void should_get_comments_of_article_success() throws Exception {
-        when(commentQueryService.findByArticleId(anyString(), eq(null))).thenReturn(Arrays.asList(commentData));
+    when(commentQueryService.findByArticleId(anyString(), eq(null)))
+        .thenReturn(Arrays.asList(commentData));
     RestAssuredMockMvc.when()
         .get("/articles/{slug}/comments", article.getSlug())
         .prettyPeek()
@@ -119,7 +130,8 @@ public class CommentsApiTest extends TestWithCurrentUser {
 
   @Test
   public void should_delete_comment_success() throws Exception {
-        when(commentRepository.findById(eq(article.getId()), eq(comment.getId()))).thenReturn(Optional.of(comment));
+    when(commentRepository.findById(eq(article.getId()), eq(comment.getId())))
+        .thenReturn(Optional.of(comment));
 
     given()
         .header("Authorization", "Token " + token)
@@ -130,13 +142,17 @@ public class CommentsApiTest extends TestWithCurrentUser {
   }
 
   @Test
-    public void should_get_403_if_not_author_of_article_or_author_of_comment_when_delete_comment() throws Exception {
+  public void should_get_403_if_not_author_of_article_or_author_of_comment_when_delete_comment()
+      throws Exception {
     User anotherUser = new User("other@example.com", "other", "123", "", "");
-        when(userRepository.findByUsername(eq(anotherUser.getUsername()))).thenReturn(Optional.of(anotherUser));
+    when(userRepository.findByUsername(eq(anotherUser.getUsername())))
+        .thenReturn(Optional.of(anotherUser));
     when(jwtService.getSubFromToken(any())).thenReturn(Optional.of(anotherUser.getId()));
-        when(userRepository.findById(eq(anotherUser.getId()))).thenReturn(Optional.ofNullable(anotherUser));
+    when(userRepository.findById(eq(anotherUser.getId())))
+        .thenReturn(Optional.ofNullable(anotherUser));
 
-        when(commentRepository.findById(eq(article.getId()), eq(comment.getId()))).thenReturn(Optional.of(comment));
+    when(commentRepository.findById(eq(article.getId()), eq(comment.getId())))
+        .thenReturn(Optional.of(comment));
     String token = jwtService.toToken(anotherUser);
     when(userRepository.findById(eq(anotherUser.getId()))).thenReturn(Optional.of(anotherUser));
     given()
@@ -145,6 +161,5 @@ public class CommentsApiTest extends TestWithCurrentUser {
         .delete("/articles/{slug}/comments/{id}", article.getSlug(), comment.getId())
         .then()
         .statusCode(403);
-
   }
 }

src/test/java/io/spring/api/CurrentUserApiTest.java

@@ -10,7 +10,9 @@ import io.restassured.module.mockmvc.RestAssuredMockMvc;
 import io.spring.JacksonCustomizations;
 import io.spring.api.security.WebSecurityConfig;
 import io.spring.application.UserQueryService;
+import io.spring.application.user.UserService;
 import io.spring.core.user.User;
+import io.spring.infrastructure.service.NaiveEncryptService;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
@@ -28,7 +30,8 @@ import org.springframework.test.web.servlet.MockMvc;
   WebSecurityConfig.class,
   JacksonCustomizations.class,
   UserService.class,
-  ValidationAutoConfiguration.class
+  ValidationAutoConfiguration.class,
+  NaiveEncryptService.class
 })
 public class CurrentUserApiTest extends TestWithCurrentUser {
 

src/test/java/io/spring/api/ListArticleApiTest.java

@@ -1,10 +1,17 @@
 package io.spring.api;
 
+import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
+import static io.spring.TestHelper.articleDataFixture;
+import static java.util.Arrays.asList;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.when;
+
 import io.restassured.module.mockmvc.RestAssuredMockMvc;
 import io.spring.JacksonCustomizations;
 import io.spring.api.security.WebSecurityConfig;
 import io.spring.application.ArticleQueryService;
 import io.spring.application.Page;
+import io.spring.application.article.ArticleCommandService;
 import io.spring.application.data.ArticleDataList;
 import io.spring.core.article.ArticleRepository;
 import org.junit.Before;
@@ -15,23 +22,16 @@ import org.springframework.boot.test.mock.mockito.MockBean;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.web.servlet.MockMvc;
 
-import static io.restassured.module.mockmvc.RestAssuredMockMvc.given;
-import static io.spring.TestHelper.articleDataFixture;
-import static java.util.Arrays.asList;
-import static org.mockito.ArgumentMatchers.eq;
-import static org.mockito.Mockito.when;
-
 @WebMvcTest(ArticlesApi.class)
 @Import({WebSecurityConfig.class, JacksonCustomizations.class})
 public class ListArticleApiTest extends TestWithCurrentUser {
-    @MockBean
+  @MockBean private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
-    @MockBean
+  @MockBean private ArticleQueryService articleQueryService;
-    private ArticleQueryService articleQueryService;
 
-    @Autowired
+  @MockBean private ArticleCommandService articleCommandService;
-    private MockMvc mvc;
+
+  @Autowired private MockMvc mvc;
 
   @Override
   @Before
@@ -42,30 +42,27 @@ public class ListArticleApiTest extends TestWithCurrentUser {
 
   @Test
   public void should_get_default_article_list() throws Exception {
-        ArticleDataList articleDataList = new ArticleDataList(
+    ArticleDataList articleDataList =
+        new ArticleDataList(
             asList(articleDataFixture("1", user), articleDataFixture("2", user)), 2);
-        when(articleQueryService.findRecentArticles(eq(null), eq(null), eq(null), eq(new Page(0, 20)), eq(null))).thenReturn(articleDataList);
+    when(articleQueryService.findRecentArticles(
-        RestAssuredMockMvc.when()
+            eq(null), eq(null), eq(null), eq(new Page(0, 20)), eq(null)))
-            .get("/articles")
+        .thenReturn(articleDataList);
-            .prettyPeek()
+    RestAssuredMockMvc.when().get("/articles").prettyPeek().then().statusCode(200);
-            .then()
-            .statusCode(200);
   }
 
   @Test
   public void should_get_feeds_401_without_login() throws Exception {
-        RestAssuredMockMvc.when()
+    RestAssuredMockMvc.when().get("/articles/feed").prettyPeek().then().statusCode(401);
-            .get("/articles/feed")
-            .prettyPeek()
-            .then()
-            .statusCode(401);
   }
 
   @Test
   public void should_get_feeds_success() throws Exception {
-        ArticleDataList articleDataList = new ArticleDataList(
+    ArticleDataList articleDataList =
+        new ArticleDataList(
             asList(articleDataFixture("1", user), articleDataFixture("2", user)), 2);
-        when(articleQueryService.findUserFeed(eq(user), eq(new Page(0, 20)))).thenReturn(articleDataList);
+    when(articleQueryService.findUserFeed(eq(user), eq(new Page(0, 20))))
+        .thenReturn(articleDataList);
 
     given()
         .header("Authorization", "Token " + token)

src/test/java/io/spring/api/UsersApiTest.java

@@ -12,6 +12,7 @@ import io.spring.JacksonCustomizations;
 import io.spring.api.security.WebSecurityConfig;
 import io.spring.application.UserQueryService;
 import io.spring.application.data.UserData;
+import io.spring.application.user.UserService;
 import io.spring.core.service.JwtService;
 import io.spring.core.user.User;
 import io.spring.core.user.UserRepository;
@@ -46,6 +47,9 @@ public class UsersApiTest {
   @MockBean private JwtService jwtService;
 
   @MockBean private UserReadService userReadService;
+
+  @MockBean private UserService userService;
+
   private String defaultAvatar;
 
   @Before
@@ -64,6 +68,8 @@ public class UsersApiTest {
     UserData userData = new UserData(user.getId(), email, username, "", defaultAvatar);
     when(userReadService.findById(any())).thenReturn(userData);
 
+    when(userService.createUser(any())).thenReturn(user);
+
     when(userRepository.findByUsername(eq(username))).thenReturn(Optional.empty());
     when(userRepository.findByEmail(eq(email))).thenReturn(Optional.empty());
 
@@ -82,7 +88,7 @@ public class UsersApiTest {
         .body("user.image", equalTo(defaultAvatar))
         .body("user.token", equalTo("123"));
 
-    verify(userRepository).save(any());
+    verify(userService).createUser(any());
   }
 
   @Test

src/test/java/io/spring/application/article/ArticleQueryServiceTest.java

@@ -1,5 +1,10 @@
 package io.spring.application.article;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
 import io.spring.application.ArticleQueryService;
 import io.spring.application.Page;
 import io.spring.application.data.ArticleData;
@@ -14,6 +19,8 @@ import io.spring.core.user.UserRepository;
 import io.spring.infrastructure.repository.MyBatisArticleFavoriteRepository;
 import io.spring.infrastructure.repository.MyBatisArticleRepository;
 import io.spring.infrastructure.repository.MyBatisUserRepository;
+import java.util.Arrays;
+import java.util.Optional;
 import org.joda.time.DateTime;
 import org.junit.Before;
 import org.junit.Test;
@@ -23,32 +30,22 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.context.junit4.SpringRunner;
 
-import java.util.Optional;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
-
 @RunWith(SpringRunner.class)
 @MybatisTest
 @Import({
   ArticleQueryService.class,
   MyBatisUserRepository.class,
   MyBatisArticleRepository.class,
-    MyBatisArticleFavoriteRepository.class})
+  MyBatisArticleFavoriteRepository.class
+})
 public class ArticleQueryServiceTest {
-    @Autowired
+  @Autowired private ArticleQueryService queryService;
-    private ArticleQueryService queryService;
 
-    @Autowired
+  @Autowired private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
-    @Autowired
+  @Autowired private UserRepository userRepository;
-    private UserRepository userRepository;
 
-    @Autowired
+  @Autowired private ArticleFavoriteRepository articleFavoriteRepository;
-    private ArticleFavoriteRepository articleFavoriteRepository;
 
   private User user;
   private Article article;
@@ -57,7 +54,9 @@ public class ArticleQueryServiceTest {
   public void setUp() {
     user = new User("aisensiy@gmail.com", "aisensiy", "123", "", "");
     userRepository.save(user);
-        article = new Article("test", "desc", "body", new String[]{"java", "spring"}, user.getId(), new DateTime());
+    article =
+        new Article(
+            "test", "desc", "body", Arrays.asList("java", "spring"), user.getId(), new DateTime());
     articleRepository.save(article);
   }
 
@@ -90,15 +89,24 @@ public class ArticleQueryServiceTest {
 
   @Test
   public void should_get_default_article_list() {
-        Article anotherArticle = new Article("new article", "desc", "body", new String[]{"test"}, user.getId(), new DateTime().minusHours(1));
+    Article anotherArticle =
+        new Article(
+            "new article",
+            "desc",
+            "body",
+            Arrays.asList("test"),
+            user.getId(),
+            new DateTime().minusHours(1));
     articleRepository.save(anotherArticle);
 
-        ArticleDataList recentArticles = queryService.findRecentArticles(null, null, null, new Page(), user);
+    ArticleDataList recentArticles =
+        queryService.findRecentArticles(null, null, null, new Page(), user);
     assertEquals(recentArticles.getCount(), 2);
     assertEquals(recentArticles.getArticleDatas().size(), 2);
     assertEquals(recentArticles.getArticleDatas().get(0).getId(), article.getId());
 
-        ArticleDataList nodata = queryService.findRecentArticles(null, null, null, new Page(2, 10), user);
+    ArticleDataList nodata =
+        queryService.findRecentArticles(null, null, null, new Page(2, 10), user);
     assertEquals(nodata.getCount(), 2);
     assertEquals(nodata.getArticleDatas().size(), 0);
   }
@@ -108,10 +116,12 @@ public class ArticleQueryServiceTest {
     User anotherUser = new User("other@email.com", "other", "123", "", "");
     userRepository.save(anotherUser);
 
-        Article anotherArticle = new Article("new article", "desc", "body", new String[]{"test"}, anotherUser.getId());
+    Article anotherArticle =
+        new Article("new article", "desc", "body", Arrays.asList("test"), anotherUser.getId());
     articleRepository.save(anotherArticle);
 
-        ArticleDataList recentArticles = queryService.findRecentArticles(null, user.getUsername(), null, new Page(), user);
+    ArticleDataList recentArticles =
+        queryService.findRecentArticles(null, user.getUsername(), null, new Page(), user);
     assertEquals(recentArticles.getArticleDatas().size(), 1);
     assertEquals(recentArticles.getCount(), 1);
   }
@@ -121,13 +131,16 @@ public class ArticleQueryServiceTest {
     User anotherUser = new User("other@email.com", "other", "123", "", "");
     userRepository.save(anotherUser);
 
-        Article anotherArticle = new Article("new article", "desc", "body", new String[]{"test"}, anotherUser.getId());
+    Article anotherArticle =
+        new Article("new article", "desc", "body", Arrays.asList("test"), anotherUser.getId());
     articleRepository.save(anotherArticle);
 
     ArticleFavorite articleFavorite = new ArticleFavorite(article.getId(), anotherUser.getId());
     articleFavoriteRepository.save(articleFavorite);
 
-        ArticleDataList recentArticles = queryService.findRecentArticles(null, null, anotherUser.getUsername(), new Page(), anotherUser);
+    ArticleDataList recentArticles =
+        queryService.findRecentArticles(
+            null, null, anotherUser.getUsername(), new Page(), anotherUser);
     assertEquals(recentArticles.getArticleDatas().size(), 1);
     assertEquals(recentArticles.getCount(), 1);
     ArticleData articleData = recentArticles.getArticleDatas().get(0);
@@ -138,10 +151,12 @@ public class ArticleQueryServiceTest {
 
   @Test
   public void should_query_article_by_tag() {
-        Article anotherArticle = new Article("new article", "desc", "body", new String[]{"test"}, user.getId());
+    Article anotherArticle =
+        new Article("new article", "desc", "body", Arrays.asList("test"), user.getId());
     articleRepository.save(anotherArticle);
 
-        ArticleDataList recentArticles = queryService.findRecentArticles("spring", null, null, new Page(), user);
+    ArticleDataList recentArticles =
+        queryService.findRecentArticles("spring", null, null, new Page(), user);
     assertEquals(recentArticles.getArticleDatas().size(), 1);
     assertEquals(recentArticles.getCount(), 1);
     assertEquals(recentArticles.getArticleDatas().get(0).getId(), article.getId());
@@ -158,7 +173,8 @@ public class ArticleQueryServiceTest {
     FollowRelation followRelation = new FollowRelation(anotherUser.getId(), user.getId());
     userRepository.saveRelation(followRelation);
 
-        ArticleDataList recentArticles = queryService.findRecentArticles(null, null, null, new Page(), anotherUser);
+    ArticleDataList recentArticles =
+        queryService.findRecentArticles(null, null, null, new Page(), anotherUser);
     assertEquals(recentArticles.getCount(), 1);
     ArticleData articleData = recentArticles.getArticleDatas().get(0);
     assertTrue(articleData.getProfileData().isFollowing());

src/test/java/io/spring/application/comment/CommentQueryServiceTest.java

@@ -1,5 +1,8 @@
 package io.spring.application.comment;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
 import io.spring.application.CommentQueryService;
 import io.spring.application.data.CommentData;
 import io.spring.core.article.Article;
@@ -12,6 +15,9 @@ import io.spring.core.user.UserRepository;
 import io.spring.infrastructure.repository.MyBatisArticleRepository;
 import io.spring.infrastructure.repository.MyBatisCommentRepository;
 import io.spring.infrastructure.repository.MyBatisUserRepository;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -20,27 +26,22 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.context.junit4.SpringRunner;
 
-import java.util.List;
-import java.util.Optional;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
 @MybatisTest
 @RunWith(SpringRunner.class)
-@Import({MyBatisCommentRepository.class, MyBatisUserRepository.class, CommentQueryService.class, MyBatisArticleRepository.class})
+@Import({
+  MyBatisCommentRepository.class,
+  MyBatisUserRepository.class,
+  CommentQueryService.class,
+  MyBatisArticleRepository.class
+})
 public class CommentQueryServiceTest {
-    @Autowired
+  @Autowired private CommentRepository commentRepository;
-    private CommentRepository commentRepository;
 
-    @Autowired
+  @Autowired private UserRepository userRepository;
-    private UserRepository userRepository;
 
-    @Autowired
+  @Autowired private CommentQueryService commentQueryService;
-    private CommentQueryService commentQueryService;
 
-    @Autowired
+  @Autowired private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
   private User user;
 
@@ -63,7 +64,7 @@ public class CommentQueryServiceTest {
 
   @Test
   public void should_read_comments_of_article() {
-        Article article = new Article("title", "desc", "body", new String[]{"java"}, user.getId());
+    Article article = new Article("title", "desc", "body", Arrays.asList("java"), user.getId());
     articleRepository.save(article);
 
     User user2 = new User("user2@email.com", "user2", "123", "", "");
@@ -77,6 +78,5 @@ public class CommentQueryServiceTest {
 
     List<CommentData> comments = commentQueryService.findByArticleId(article.getId(), user);
     assertEquals(comments.size(), 2);
-
   }
 }

src/test/java/io/spring/application/tag/TagsQueryServiceTest.java

@@ -1,9 +1,12 @@
 package io.spring.application.tag;
 
+import static org.junit.Assert.assertTrue;
+
 import io.spring.application.TagsQueryService;
 import io.spring.core.article.Article;
 import io.spring.core.article.ArticleRepository;
 import io.spring.infrastructure.repository.MyBatisArticleRepository;
+import java.util.Arrays;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mybatis.spring.boot.test.autoconfigure.MybatisTest;
@@ -11,21 +14,17 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.context.junit4.SpringRunner;
 
-import static org.junit.Assert.assertTrue;
-
 @RunWith(SpringRunner.class)
 @MybatisTest
 @Import({TagsQueryService.class, MyBatisArticleRepository.class})
 public class TagsQueryServiceTest {
-    @Autowired
+  @Autowired private TagsQueryService tagsQueryService;
-    private TagsQueryService tagsQueryService;
 
-    @Autowired
+  @Autowired private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
   @Test
   public void should_get_all_tags() {
-        articleRepository.save(new Article("test", "test", "test", new String[]{"java"}, "123"));
+    articleRepository.save(new Article("test", "test", "test", Arrays.asList("java"), "123"));
     assertTrue(tagsQueryService.allTags().contains("java"));
   }
 }

src/test/java/io/spring/core/article/ArticleTest.java

@@ -1,39 +1,40 @@
 package io.spring.core.article;
 
-import org.junit.Test;
-
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
 
+import java.util.Arrays;
+import org.junit.Test;
+
 public class ArticleTest {
 
   @Test
   public void should_get_right_slug() {
-        Article article = new Article("a new   title", "desc", "body", new String[]{"java"}, "123");
+    Article article = new Article("a new   title", "desc", "body", Arrays.asList("java"), "123");
     assertThat(article.getSlug(), is("a-new-title"));
   }
 
   @Test
   public void should_get_right_slug_with_number_in_title() {
-        Article article = new Article("a new title 2", "desc", "body", new String[]{"java"}, "123");
+    Article article = new Article("a new title 2", "desc", "body", Arrays.asList("java"), "123");
     assertThat(article.getSlug(), is("a-new-title-2"));
   }
 
   @Test
   public void should_get_lower_case_slug() {
-        Article article = new Article("A NEW TITLE", "desc", "body", new String[]{"java"}, "123");
+    Article article = new Article("A NEW TITLE", "desc", "body", Arrays.asList("java"), "123");
     assertThat(article.getSlug(), is("a-new-title"));
   }
 
   @Test
   public void should_handle_other_language() {
-        Article article = new Article("中文：标题", "desc", "body", new String[]{"java"}, "123");
+    Article article = new Article("中文：标题", "desc", "body", Arrays.asList("java"), "123");
     assertThat(article.getSlug(), is("中文-标题"));
   }
 
   @Test
   public void should_handle_commas() {
-        Article article = new Article("what?the.hell,w", "desc", "body", new String[]{"java"}, "123");
+    Article article = new Article("what?the.hell,w", "desc", "body", Arrays.asList("java"), "123");
     assertThat(article.getSlug(), is("what-the-hell-w"));
   }
 }

src/test/java/io/spring/infrastructure/article/ArticleRepositoryTransactionTest.java

@@ -1,10 +1,13 @@
 package io.spring.infrastructure.article;
 
+import static org.junit.Assert.assertNull;
+
 import io.spring.core.article.Article;
 import io.spring.core.article.ArticleRepository;
 import io.spring.core.user.User;
 import io.spring.core.user.UserRepository;
 import io.spring.infrastructure.mybatis.mapper.ArticleMapper;
+import java.util.Arrays;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -12,35 +15,29 @@ import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabas
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.context.junit4.SpringRunner;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-
 @RunWith(SpringRunner.class)
 @SpringBootTest
 @AutoConfigureTestDatabase
 public class ArticleRepositoryTransactionTest {
-    @Autowired
+  @Autowired private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
-    @Autowired
+  @Autowired private UserRepository userRepository;
-    private UserRepository userRepository;
-
-    @Autowired
-    private ArticleMapper articleMapper;
 
+  @Autowired private ArticleMapper articleMapper;
 
   @Test
   public void transactional_test() {
     User user = new User("aisensiy@gmail.com", "aisensiy", "123", "bio", "default");
     userRepository.save(user);
-        Article article = new Article("test", "desc", "body", new String[]{"java", "spring"}, user.getId());
+    Article article =
+        new Article("test", "desc", "body", Arrays.asList("java", "spring"), user.getId());
     articleRepository.save(article);
-        Article anotherArticle = new Article("test", "desc", "body", new String[]{"java", "spring", "other"}, user.getId());
+    Article anotherArticle =
+        new Article("test", "desc", "body", Arrays.asList("java", "spring", "other"), user.getId());
     try {
       articleRepository.save(anotherArticle);
     } catch (Exception e) {
       assertNull(articleMapper.findTag("other"));
     }
   }
-
 }

src/test/java/io/spring/infrastructure/article/MyBatisArticleRepositoryTest.java

@@ -1,5 +1,10 @@
 package io.spring.infrastructure.article;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertTrue;
+
 import io.spring.core.article.Article;
 import io.spring.core.article.ArticleRepository;
 import io.spring.core.article.Tag;
@@ -7,6 +12,8 @@ import io.spring.core.user.User;
 import io.spring.core.user.UserRepository;
 import io.spring.infrastructure.repository.MyBatisArticleRepository;
 import io.spring.infrastructure.repository.MyBatisUserRepository;
+import java.util.Arrays;
+import java.util.Optional;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -15,31 +22,21 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Import;
 import org.springframework.test.context.junit4.SpringRunner;
 
-import java.util.Optional;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertTrue;
-
 @MybatisTest
 @RunWith(SpringRunner.class)
 @Import({MyBatisArticleRepository.class, MyBatisUserRepository.class})
 public class MyBatisArticleRepositoryTest {
-    @Autowired
+  @Autowired private ArticleRepository articleRepository;
-    private ArticleRepository articleRepository;
 
-    @Autowired
+  @Autowired private UserRepository userRepository;
-    private UserRepository userRepository;
 
   private Article article;
 
-
   @Before
   public void setUp() {
     User user = new User("aisensiy@gmail.com", "aisensiy", "123", "bio", "default");
     userRepository.save(user);
-        article = new Article("test", "desc", "body", new String[]{"java", "spring"}, user.getId());
+    article = new Article("test", "desc", "body", Arrays.asList("java", "spring"), user.getId());
   }
 
   @Test