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java - Spring boot userRepository.findAll() 显示次数过多导致stackoverflow错误

问题描述

我有这段代码，但我在浏览器上的输出不是我想要的 

@GetMapping(path = "/all")
public @ResponseBody List<User> getAllUsers() {
    return userRepository.findAll();
}

输出：

[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users":[{"id":4,"firstName":"busayo","lastName":"amowe","email":"amoweolubusayo@gmail.com","password":"$2a$10$09kGDhlEp.Xmj0ocDjGLTO.03z.kGQKm2ZHcsNetDpH0r6m1rkVIu","roles":[{"id":1,"name":"ROLE_ADMIN","users"

不是应该打印一次吗？它说 StackOverFlow 错误，我的 getJson 函数无法显示它。我能做些什么？

标签： javajsonspring-bootjackson

解决方案

user您在和user role实体之间存在循环依赖关系。

为了将您的响应返回给客户端，您List<User>必须进行序列化。您必须告诉杰克逊如何处理循环，否则它将因堆栈溢出异常而失败。

public class User {

    @JsonBackReference
    public List<Role> roles;

    // ...       

}

public class Role {

    @JsonManagedReference
    public List<User> users;

    // ...       

}

有关双向关系的 Jackson 教程，请参阅https://www.baeldung.com/jackson-bidirectional-relationships-and-infinite-recursion

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