Spring boot userRepository.findAll (), отображающий слишком много раз и вызывающий ошибку переполнения стека

Question

У меня есть этот код, но мой вывод в браузере не тот, который я хочу

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

Вывод:

[{"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"

Разве он не должен быть напечатан один раз?Он говорит, что ошибка StackOverFlow и моя функция getJson не может ее отобразить.Что я могу сделать?

Answer 1

У вас есть циклическая зависимость между user и user role сущностями.

Чтобы вернуть ваш ответ клиенту, ваш List<User> должен быть сериализован.Вы должны указать Джексону, как обрабатывать циклы, иначе произойдет сбой с исключением переполнения стека.

public class User {

    @JsonBackReference
    public List<Role> roles;

    // ...       

}

public class Role {

    @JsonManagedReference
    public List<User> users;

    // ...       

}

Учебное пособие Джексона относительно двунаправленных отношений см. https://www.baeldung.com/jackson-bidirectional-relationships-and-infinite-recursion