update user info

src/main/java/io/spring/infrastructure/user/MyBatisUserRepository.java

@@ -18,7 +18,16 @@ public class MyBatisUserRepository implements UserRepository {
 
     @Override
     public void save(User user) {
-        userMapper.save(user);
+        if (userMapper.findById(user.getId()) == null) {
+            userMapper.insert(user);
+        } else {
+            userMapper.update(user);
+        }
+    }
+
+    @Override
+    public Optional<User> findById(String id) {
+        return Optional.ofNullable(userMapper.findById(id));
     }
 
     @Override

src/main/java/io/spring/infrastructure/user/UserMapper.java

@@ -8,8 +8,12 @@ import org.springframework.stereotype.Component;
 @Component
 @Mapper
 public interface UserMapper {
-    void save(@Param("user") User user);
+    void insert(@Param("user") User user);
 
     User findByUsername(@Param("username") String username);
     User findByEmail(@Param("email") String email);
+
+    User findById(@Param("id") String id);
+
+    void update(@Param("user") User user);
 }