Controller 层
// 接收 Request DTO
public ResponseEntity<UserDTO> createUser(
@RequestBody @Valid UserCreateRequest request) { ... }
↓ 转换为 Service 需要的参数
Service 层
public UserDTO createUser(UserCreateParam param) {
User user = param.toEntity(); // 转换为 Entity
userRepository.save(user);
return UserDTO.from(user); // Entity → DTO
}
↓ 转换为 Repository 需要的 Entity
Repository 层
public interface UserRepository
extends JpaRepository<User, Long> { }
↑ 返回 Entity，转换为 DTO
返回给客户端
{ "id": 10001, "username": "张三",
"email": "zhangsan@example.com", "createdAt": "2024-01-15T10:30:00Z" }