休眠验证器导致多对多关系无法保存 [英] Hibernate validator causing many to many relationship to not save
问题描述
我在用户和角色之间有一个ManyToMany关系.我在用户"中的角色集上有一个自定义的休眠验证约束.
I have a ManyToMany relationship between User and Role. I have a custom hibernate validation constraint on my roles Set in User.
在@PostConstruct中，我使用spring-data-jpa中的标准JpaRepository将初始角色(ADMIN，USER)保存到数据库中.然后，我使用管理员角色创建一个初始用户.
In a @PostConstruct I save the initial roles (ADMIN, USER) to the database using standard JpaRepository from spring-data-jpa. I then create an initial user using the admin role.
如果没有自定义验证，则关联将正确保存，并且在user_role联接表中看到一个条目.如果我已通过验证，则将用户插入到用户表中，但未在user_role表中进行输入.返回的实体在角色集中具有角色，但不会保存到角色表中. D B.该代码总结如下.我不明白如何使用RoleRepo来获取所有角色会以任何方式破坏保存，但确实如此.
If I do not have my custom validation, the association is saved correctly and I see an entry in user_role join table. If I have the validation, the user is inserted into the user table, but without an entry into user_role table. The returned entity has the role in the roles set, but it is not saved into the DB. The code is summarized below. I cannot understand how using the RoleRepo to fetch all of the roles could in any way break the save, but it does.
class User {
@Id
String username;
@ValidOption
@ManyToMany(cascade = {CascadeType.ALL //for example}, fetch=FetchType.EAGER)
Set<Role> roles;
}
class Role {
@Id
String name;
}
class CustomValidator implements ConstraintValidator<ValidOption, Object> {
RoleRepository roleRepo; //injected by spring... have spring factory
@Override
public boolean isValid(Object value, ConstraintValidatorContext context){
roleRepo.findAll() //<-------------- THIS CALL BREAKS THE SAVE
return true;
}
}
@Component
class UserCreator {
RoleRepository roleRepo;
UserRepo userRepo;
@PostConstruct
void setup(){
Role admin = roleRepo.saveAndFlush(new Role('ADMIN'));
roleRepo.saveAndFlush(new Role('USER'));
User user = new User('admin', Collections.singleton(admin));
userRepo.save(user); //<------ DOES NOT INSERT ADMIN INTO USER_ROLE JOIN TABLE
}
}
这完全符合我删除自定义验证器时的预期效果.如果我不在PostConstruct中运行此程序并将其安排在其他线程中，则它也可能会起作用，我需要检查一下.
This works 100% exactly the way I would expect if I remove the custom validator. It may also work if I don't run this in PostConstruct and schedule it in a different thread, I need to check that.
Project with reproducible failing test case: https://github.com/tjhelmuth/SPR-22533/blob/master/src/test/java/spr22533/bug/BugExample.java
推荐答案
在验证过程中不能保证在验证期间访问EntityManager.
Accessing the EntityManager during validation is not guaranteed to work during validation.
验证发生在生命周期回调方法"中. 对于这些，以下限制适用(Java持久性规范2.2；第3.5.2节生命周期回调方法"):
Validation happens in "lifecycle callback methods". For these the following restriction applies (Java Persistence Specification 2.2; Section 3.5.2 Lifecycle Callback Methods):
通常，可移植应用程序的生命周期方法不应调用EntityManager或查询操作，访问其他实体实例或修改同一持久性上下文内的关系.生命周期回调方法可以修改在其上调用它的实体的非关系状态.
In general, the lifecycle method of a portable application should not invoke EntityManager or query operations, access other entity instances, or modify relationships within the same persistence context. A lifecycle callback method may modify the non-relationship state of the entity on which it is invoked.
要使其正常工作，请使用单独的EntityManager，由于它运行不同的事务，因此当然可能会遇到一组不同的更改.
To make it work, use a separate EntityManager, which of course might suffer from seeing a different set of changes since it runs a different transaction.
另请参阅:执行EntityManager的正确方法休眠验证期间进行查询
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