Spring启动JPA - OneToMany关系导致无限循环

问题描述

我有一个简单的@OneToMany关系的两个对象，如下所示：

父：

 @Entity 
 public class ParentAccount {
 
 @Id 
 @GeneratedValue 
 private long id; 
私人字符串名称; 
 
 @OneToMany（fetch = FetchType.EAGER，mappedBy =parentAccount）
 private Set< LinkedAccount>关联账户; 
 
 $ b  

儿童：

  @Entity 
 public class LinkedAccount {
 
 @Id 
 @GeneratedValue 
 private long id; 
 
 @ManyToOne（可选= false）
私人ParentAccount parentAccount; 
 
私人字符串名称; 
 
 // JPA的空构造函数
 public LinkedAccount（）{
} 
 
} 
  

我使用Spring CrudRepository 来操作这些实体。但是，当调用 ParentAccount parent = parentAccountRepository.findOne（id）; 时，某种无限循环开始发生，并且休眠在整个控制台中传播：

  Hibernate：select linkedacco0_.parent_account_id as parent_a6_1_0_，linkedacco0_.id as id1_0_0_，linkedacco0_.id as id1_0_1_，linkedacco0_.aws_id as aws_id2_0_1_，linkedacco0_.key_id as key_id3_0_1_ ，将linked0_.name作为name4_0_1_，linkedacco0_.parent_account_id作为parent_a6_0_1_，linkedacco0_.secret_key作为secret_k5_0_1_，从linked_account linkedacco0_，其中linkedacco0_.parent_account_id =？ 
  

我尝试将获取类型更改为LAZY，但随后出现此错误：

  org.hibernate.LazyInitializationException：无法懒惰地初始化一个角色集合：com.berrycloud.scheduler.model.ParentAccount.linkedAccounts，无法初始化代理 - 没有会话
  

（它似乎试图在事务性上下文之外执行延迟加载）。

这是我的CRUD存储库：

  @Repository 
公共接口ParentAccountRepository扩展CrudRepository< ParentAccount，Long> {
} 
  

有人能告诉我如何解决这个问题吗？我更喜欢EAGER获取的解决方案。感谢您的任何提示

编辑：这里是我正在使用的模式

  id BIGINT auto_increment，
 name VARCHAR（80）null，
 PRIMARY KEY（`id`）
）; 
 
 CREATE TABLE linked_account（
 id BIGINT auto_increment，
 parent_account_id BIGINT，
 name VARCHAR（80）null，
 FOREIGN KEY（`parent_account_id`）参考`parent_account`（`id`），
 PRIMARY KEY（`id`）
）; 
  

解决方案

问题解决了。我在引用ParentAccount的LinkedAccount中使用了自定义的 @toString 方法。我不知道这可能会导致任何问题，因此我没有在我的问题中包含toString。

显然，这导致了无限循环的延迟加载和删除这个参考解决了这个问题。

I have a two objects with simple @OneToMany relationship which looks as follows:

parent:

@Entity
public class ParentAccount {

  @Id
  @GeneratedValue
  private long id;
  private String name;

  @OneToMany(fetch = FetchType.EAGER, mappedBy = "parentAccount")
  private Set<LinkedAccount> linkedAccounts;

}

child:

@Entity
public class LinkedAccount {

  @Id
  @GeneratedValue
  private long id;

  @ManyToOne(optional = false)
  private ParentAccount parentAccount;

  private String name;

  // empty constructor for JPA
  public LinkedAccount() {
  }

}

I ma using Spring CrudRepository to operate with these entities. However, when calling ParentAccount parent = parentAccountRepository.findOne(id);, some kind of infinite loop starts happening and hibernate spams this all over the console:

Hibernate: select linkedacco0_.parent_account_id as parent_a6_1_0_, linkedacco0_.id as id1_0_0_, linkedacco0_.id as id1_0_1_, linkedacco0_.aws_id as aws_id2_0_1_, linkedacco0_.key_id as key_id3_0_1_, linkedacco0_.name as name4_0_1_, linkedacco0_.parent_account_id as parent_a6_0_1_, linkedacco0_.secret_key as secret_k5_0_1_ from linked_account linkedacco0_ where linkedacco0_.parent_account_id=?

I tried changed the fetch type to LAZY but then I get this error:

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.berrycloud.scheduler.model.ParentAccount.linkedAccounts, could not initialize proxy - no Session

(It seems that it is trying to do the lazy load outside of the transactional context).

This is my CRUD repository:

@Repository
public interface ParentAccountRepository extends CrudRepository<ParentAccount, Long> {
}

Could someone tell me how to resolve this issue? I would prefer the solution with EAGER fetch. Thank you for any tips

EDIT: here is the schema I am using

CREATE TABLE parent_account (
    id BIGINT auto_increment,
    name VARCHAR(80) null,
    PRIMARY KEY (`id`)
);

CREATE TABLE linked_account (
    id BIGINT auto_increment,
    parent_account_id BIGINT,
    name VARCHAR(80) null,
    FOREIGN KEY (`parent_account_id`) REFERENCES `parent_account` (`id`),
    PRIMARY KEY (`id`)
);

解决方案

Problem solved. I was using a custom @toString method in the LinkedAccount which was referencing the ParentAccount. I had no idea that this could cause any problem and therefor I did not include the toString in my question.

Apparently, this was causing an infinite loop of lazy loading and removing this reference fixed the problem.

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