should update article

src/main/java/io/spring/infrastructure/article/ArticleMapper.java

@@ -18,4 +18,8 @@ public interface ArticleMapper {
     void insertTag(@Param("tag") Tag tag);
 
     void insertArticleTagRelation(@Param("articleId") String articleId, @Param("tagId") String tagId);
+
+    Article findBySlug(@Param("slug") String slug);
+
+    void update(@Param("article") Article article);
 }

src/main/java/io/spring/infrastructure/article/MyBatisArticleRepository.java

@@ -16,12 +16,15 @@ public class MyBatisArticleRepository implements ArticleRepository {
     }
 
     @Override
-    public String toSlug(String title) {
-        return title.toLowerCase().replace(' ', '-');
+    public void save(Article article) {
+        if (articleMapper.findById(article.getId()) == null) {
+            createNew(article);
+        } else {
+            articleMapper.update(article);
+        }
     }
 
-    @Override
-    public void save(Article article) {
+    private void createNew(Article article) {
         articleMapper.insert(article);
         for (Tag tag : article.getTags()) {
             if (!articleMapper.findTag(tag.getName())) {
@@ -35,4 +38,9 @@ public class MyBatisArticleRepository implements ArticleRepository {
     public Optional<Article> findById(String id) {
         return Optional.ofNullable(articleMapper.findById(id));
     }
+
+    @Override
+    public Optional<Article> findBySlug(String slug) {
+        return Optional.ofNullable(articleMapper.findBySlug(slug));
+    }
 }