如何将(@autowired)@服务注入ConstraintValidator？

Question

我有一些UserService对用户实体进行操作。我创建了自己的注释和ConstraintValidator类作为实现

我需要将UserService注入到ConstraintValidator中。而且，正如spring文档所说，在注册bean之后：

<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"/>

不幸的是，它对我没有作用。我在字段（在实现ConstraintValidator的类内）使用NullPointerException累加stacktrace：

@Autowired
private UserService userService; //here

在呼叫服务时

@Override
public boolean isValid(String username, ConstraintValidatorContext constraintValidatorContext) {
    personService.doSomethingWithService(); //here
    return true;
}

因此，这意味着UserService没有正确注入。我还尝试使用ApplicationContextAware-在我的ConstraintValidator类中实现它，获取上下文并找到bean：

(UserService) context.getBean("userService");

java.lang.NullPointerException
    com.reportme.model.validation.UsernameAvailableValidator.isValid(UsernameAvailableValidator.java:20)
    com.reportme.model.validation.UsernameAvailableValidator.isValid(UsernameAvailableValidator.java:9)
    org.hibernate.validator.internal.engine.ConstraintTree.validateSingleConstraint(ConstraintTree.java:308)
    org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:180)
    org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:124)
    org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:85)
    org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:463)
//...

org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction
    org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:526)
    org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:757)
    org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:726)
//...

javax.persistence.RollbackException: Error while committing the transaction
    org.hibernate.jpa.internal.TransactionImpl.commit(TransactionImpl.java:94)
    org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:517)

Answer 1

我的环境是spring-boot，下面的代码对我的验证类进行了org.springframework.stereoType.component注释。

@Component
public class FooValidator implements ConstraintValidator<Foo, Object> {

  @Autowired
  MyService service;

  @Override
  public void initialize(Foo constraintAnnotation) {
  }

  @Override
  public boolean isValid(Object value, ConstraintValidatorContext context) {
    return service.isValid(value);
  }
}