休眠集null没有保存，则数据已被删除

Question

实体：(省略了一些属性(

存储：

@Entity
@Table(name = "t_storage")
public class Storage implements Serializable {
private static final long serialVersionUID = -8067092629525887737L;
@Id
@GeneratedValue
private Long id;
@Column
private String name;
@ManyToMany(fetch = FetchType.LAZY,cascade= CascadeType.REFRESH)
@JoinTable(name = "t_purchase_storage", joinColumns = {@JoinColumn(name = "storage_id") },inverseJoinColumns = { @JoinColumn(name = "purchase_id") })
private List<Purchase> purchases = Lists.newArrayList();
@ManyToMany(fetch = FetchType.LAZY,cascade=CascadeType.ALL)
@JoinTable(name = "auth_user_storage", joinColumns = {@JoinColumn(name = "storage_id")}, inverseJoinColumns =
{@JoinColumn(name = "user_id")})
private List<User> users = new ArrayList<>();
}

用户：

@Entity
@Table(name = "auth_user")
public class User implements Serializable {
private static final long serialVersionUID = 2577286098148701829L;
@Id
@GeneratedValue
private Long id;

@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(name = "auth_user_storage", joinColumns = {@JoinColumn(name = "user_id")}, inverseJoinColumns =
{@JoinColumn(name = "storage_id")})
private Set<Storage> storages = Sets.newHashSet();
@Column(name = "username")
private String username;
}

步骤：1.想要选择一些存储

List<Storage> storageList = storageService.findAllStorage(null);
storageList.forEach(store -> {
store.setPurchases(null);
store.setCheckUsers(null);
store.setUsers(null);
store.setStorageBins(null);
});
return ResponseEntity.ok(JsonResult.success(storageList));

2.AopLog调用UserServiceImpl方法

controllerLog.setOperatorName(userService.findUserNameById(id));

该serviceImpl具有@Transaction

@Service
@Transactional
@Slf4j
public class UserServiceImpl implements UserService {
@Override
public String findUserNameById(Long userId) {
return userRepository.findUsernameById(userId);
}
}

执行userRepository.findUsernameById时，则删除了以前的setnull属性

日志：

2021-03-29 17:04:06.991 [http-nio-7779-exec-1] INFO  com.~~.api.web.log.AopLog - 【返回值】：<200 OK,class   JsonResult {
code: 001
msg: ok
data: [com.~~.entity.Storage@21]
},{}>
Hibernate: delete from t_checkuser_storage where storage_id=?  
Hibernate: delete from t_purchase_storage where storage_id=?  
Hibernate: delete from auth_user_storage where storage_id=?  
Hibernate: select username from auth_user where id=?  

solve
删除serviceImpl上的事务注释，就没有问题了。

或未设置为null，返回VO。

问题
我没有执行任何保存或删除操作。为什么要删除留空的属性？

Answer 1

使用@Transactional时，查询返回的实体在事务期间进行管理。这意味着在提交时，应用于实体的任何更改都将传播到数据库。因此，将这些值设置为null相当于数据库上的更新查询。

删除@Transactional时，查询返回实体后，该实体将立即停止管理。因此，更改不会传播到数据库。