spring循环依赖解决方法

错误情况

@Service
public class PersonServiceImpl implements PersonService {  
@Autowired
private GroupService groupService;
} 

....

@Service
public class GroupServiceImpl implements GroupService {
@Autowired
private PersonService personService;
}

---

出现了一下错误：
Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name ‘personServiceImpl’: Bean with name ‘personServiceImpl’ has been injected into other beans [groupServiceImpl] in its raw version as part of a circular reference, but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using ‘getBeanNamesOfType’ with the ‘allowEagerInit’ flag turned off, for example.
原因是：PersonServiceImpl中依赖了GroupServiceImpl，GroupServiceImpl依赖了PersonServiceImpl，出现了循环依赖
在spring官网https://www.baeldung.com/circular-dependencies-in-spring中对这个异常进行了解释：

当使用构造函数注入时;如果使用其他类型的注入，应该不会发现这个问题，因为依赖项将在需要时注入，而不是在上下文加载时注入。

spring官网提供了很多解决方法，我的解决方法是将GroupServiceImpl中在注入PersonService 类时使用@Lazy注解，就是不会完全初始化PersonService ，而是创建一个代理将其注入到另一个GroupServiceImpl中。只有在第一次需要注入的PersonService 时，才会完全创建它。
将GroupServiceImpl修改如下：

@Service
public class GroupServiceImpl implements GroupService {
private PersonService personService;

@Autowired
public GroupServiceImpl(@Lazy PersonService personService) {
    this.personService = personService;
}
}

问题得到解决。

总结

在service中尽量不要注入service，否则容易出现循环注入的情况，改起来可能会特别麻烦。