Java SpringDataJPA：为什么findOne（id）在内部执行删除查询？

我有一个应用程序，使用

@manytomy

注释将两个不同的实体链接到一个父实体。我不确定我是否正确地实施了它。但当我在父实体的存储库上执行

.findOne（）

来查找它时，首先它正确地获取数据，但同时它也在内部执行删除查询，从映射表（JPA在添加@manytomy注释后自行创建的表）中删除记录。以下是生成的SQL查询和代码段：

Java类

@Entity
@Table(name = "inventory")
public class Inventory {

    @Id
    Long id;

    // many other properties

    @ManyToMany(fetch=FetchType.LAZY)
    private List<Stream> streams;

    @ManyToMany(fetch=FetchType.LAZY)
    private List<Subject> subjects;
}  

@Transactional
public class InventoryService {

  public Inventory getInventoryById(Integer id) {
      Inventory inv = invRepository.findOne(id);
      if(inv == null) {
            throw new NotFoundException("Entity not found id: "+id);
      }
      return inv;
  }
} 

Hibernate: select streams0_.inventory_id as inventor1_1_0_, streams0_.streams_id as streams_2_2_0_, stream1_.id as id1_6_1_, stream1_.stream as stream2_6_1_ from inventory_stream streams0_ inner join stream stream1_ on streams0_.streams_id=stream1_.id where streams0_.inventory_id=?
Hibernate: delete from inventory_stream where inventory_id=?
Hibernate: select subjects0_.inventory_id as inventor1_1_0_, subjects0_.subjects_id as subjects2_3_0_, subject1_.id as id1_7_1_, subject1_.subjectName as subjectN2_7_1_ from inventory_subject subjects0_ inner join subject subject1_ on subjects0_.subjects_id=subject1_.id where subjects0_.inventory_id=?
Hibernate: delete from inventory_subject where inventory_id=?  

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@Entity
@Table(name = "inventory")
public class Inventory {

    @Id
    Long id;

    // many other properties

    @ManyToMany(fetch=FetchType.LAZY)
    private List<Stream> streams;

    @ManyToMany(fetch=FetchType.LAZY)
    private List<Subject> subjects;
}  

@Transactional
public class InventoryService {

  public Inventory getInventoryById(Integer id) {
      Inventory inv = invRepository.findOne(id);
      if(inv == null) {
            throw new NotFoundException("Entity not found id: "+id);
      }
      return inv;
  }
} 

Hibernate: select streams0_.inventory_id as inventor1_1_0_, streams0_.streams_id as streams_2_2_0_, stream1_.id as id1_6_1_, stream1_.stream as stream2_6_1_ from inventory_stream streams0_ inner join stream stream1_ on streams0_.streams_id=stream1_.id where streams0_.inventory_id=?
Hibernate: delete from inventory_stream where inventory_id=?
Hibernate: select subjects0_.inventory_id as inventor1_1_0_, subjects0_.subjects_id as subjects2_3_0_, subject1_.id as id1_7_1_, subject1_.subjectName as subjectN2_7_1_ from inventory_subject subjects0_ inner join subject subject1_ on subjects0_.subjects_id=subject1_.id where subjects0_.inventory_id=?
Hibernate: delete from inventory_subject where inventory_id=?  

更新

@Entity
@Table(name = "inventory")
public class Inventory {

    @Id
    Long id;

    // many other properties

    @ManyToMany(fetch=FetchType.LAZY)
    private List<Stream> streams;

    @ManyToMany(fetch=FetchType.LAZY)
    private List<Subject> subjects;
}  

@Transactional
public class InventoryService {

  public Inventory getInventoryById(Integer id) {
      Inventory inv = invRepository.findOne(id);
      if(inv == null) {
            throw new NotFoundException("Entity not found id: "+id);
      }
      return inv;
  }
} 

Hibernate: select streams0_.inventory_id as inventor1_1_0_, streams0_.streams_id as streams_2_2_0_, stream1_.id as id1_6_1_, stream1_.stream as stream2_6_1_ from inventory_stream streams0_ inner join stream stream1_ on streams0_.streams_id=stream1_.id where streams0_.inventory_id=?
Hibernate: delete from inventory_stream where inventory_id=?
Hibernate: select subjects0_.inventory_id as inventor1_1_0_, subjects0_.subjects_id as subjects2_3_0_, subject1_.id as id1_7_1_, subject1_.subjectName as subjectN2_7_1_ from inventory_subject subjects0_ inner join subject subject1_ on subjects0_.subjects_id=subject1_.id where subjects0_.inventory_id=?
Hibernate: delete from inventory_subject where inventory_id=?  

已从applicationContext.xml（entityManagerFactory）中删除以下属性：

符合事实的

---

并从

FetchType.LAZY

更改为

FetchType.EAGER

，解决了问题，但产生了另一个问题，即当返回

库存的单个bean时，它在
列表和
列表中返回重复数据。我不认为初始问题的根本原因是
enable\u lazy\u load\u no\u trans
。
能否再次交叉检查。我刚刚尝试在我的存储库中调用findOne（如您所述创建了多对多），但它没有触发任何删除查询。@Bala，嘿，我再次检查并更新了问题。@agpt，您有没有关于执行删除查询的解决方案？@hrdkisback啊，我现在真的不记得了，但正如您在问题（更新）中看到的，我一定是沿着那条路走的。除此之外，我没有任何其他更新。好的，谢谢您的快速回复。；）