为什么我不能在 Spring Data Mongodb 中使用“更新”操作？

Question

我使用 Spring Data MongoDb 将文档保存在数据库中。

@Repository
public interface UserRepository extends MongoRepository<User, ObjectId> {

    Optional<User> findByUsername(String userName);
    
}

@Document(collection = "users")
public class User  {

    @Id
    private ObjectId id;

    @Indexed(unique = true)
    private String username;

...

@Service
public class UserUpdateServiceImpl implements UserUpdateService {

    private UserRepository repository;

    private UserMapper mapper;

    @Autowired
    public UserUpdateServiceImpl(UserRepository repository, UserMapper mapper) {
        this.repository = repository;
        this.mapper = mapper;
    }

    @Override
    public void updateDocumentInCollection(UserDto userDto) {

        User user = mapper.toEntity(userDto);

        repository.save(user);
    }
}

org.springframework.dao.IncorrectResultSizeDataAccessException: 查询 {“$java”：查询：{“用户名”：“用户”}，字段：{}，排序：{}} 返回非唯一结果。

Update_2

我使用了insert操作

/**
     * Inserts the given entity. Assumes the instance to be new to be able to apply insertion optimizations. Use the
     * returned instance for further operations as the save operation might have changed the entity instance completely.
     * Prefer using {@link #save(Object)} instead to avoid the usage of store-specific API.
     *
     * @param entity must not be {@literal null}.
     * @return the saved entity
     * @since 1.7
     */
    <S extends T> S insert(S entity);

    public void updateUser(UserDto userDto) {

        User user = mapper.toEntity(userDto);

        userRepository.insert(user);
    }

这又导致了一个错误。

org.springframework.dao.DuplicateKeyException: E11000 重复键 错误集合：mongo-spring.users 索引：id dup key: { _id: ObjectId('5f3b786085c7d32787990955') };嵌套异常是 com.mongodb.MongoWriteException: E11000 重复键错误 集合：mongo-spring.users 索引：id 复制键：{ _id: ObjectId('5f3b786085c7d32787990955') }

Update_3

我运行单元测试。

   @Test
    void updateUser() {

        UserDto user = readService.getDataOfUserByName("user");

        user.setEnabled(true);
        user.setAccountNonLocked(true);

        List<Role> authorities = user.getAuthorities();
        authorities.add(Role.ADMIN);
        user.setAuthorities(authorities);


        if(user.getUsername() != null)
            userUpdateService.updateUser(user);

    }

    @Override
    public void updateUser(UserDto userDto) {

        User user = mapper.toEntity(userDto);

        userRepository.save(user);

    }

• 映射器

public interface CommonMapper<D, E>{

    D toDto(E e);

    E toEntity(D d);

    Iterable<D> toListDto(Iterable<E> entityList);

    Iterable<E> toListEntity(Iterable<D> dtoList);
}

@Mapper(componentModel = "spring")
public interface UserMapper extends CommonMapper<UserDto, User> {
}

现在可以了。

当我尝试更新记录时，出现异常...

Answer 1

您的代码指定用户名必须是唯一的：

@Indexed(unique = true)
private String username;

但您的数据库中似乎已经有多个条目用于您尝试保存的用户的用户名。

首先，您需要清理现有的重复条目。然后你需要决定在这种情况下你想发生什么：你想更新现有的对象，或者你想返回一个错误，表明用户名已经被占用。

在这两种情况下，您都需要先查找现有用户：

User user = repository.findByUsername(userDto.getUsername());
if(user == null) {
   user = mapper.toEntity(userDto);
}
else {
   mapper.updateUserFromDto(user, userDto);
   //OR: throw an exception
}

repository.save(user);

如果您的用户实体只是 getter/setter，并且您确定 DTO 中的所有字段也都在您的实体中，您也可以重用 mapper.toEntity 进行更新，但我不建议这样做：

User user = repository.findByUsername(userDto.getUsername());
if(user == null) {
   user = mapper.toEntity(userDto);
}
else {
   User updatedUser = mapper.toEntity(userDto);
   updatedUser.setId(user.getId()); // This changes the save from insert to update
   user = updatedUser;
}

repository.save(user);