Spring about findAll() function error in my project-CodePudding

I have basicly user and role entities in my project.

@Entity
@Table(name="`User`")
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String name;
    private String username;
    private String password;
    @ManyToMany(fetch = EAGER)
    private Collection<Role> roles = new ArrayList<>();
}

@Entity
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Role {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String name;
    @ManyToMany(mappedBy = "roles")
    private List<User> users= new ArrayList<User>();

}

This is my controller class

@RestController
@RequestMapping("/api")
@RequiredArgsConstructor
public class UserResource {
    private final UserService userService;

     @GetMapping("/users")
    public ResponseEntity<List<User>> getUsers(){

        return ResponseEntity.ok().body(userService.getUsers());
    }

And this is my UserManager class

@Service @RequiredArgsConstructor @Transactional @Slf4j
public class UserManager implements UserService {
    private final UserRepo userRepo;
    private final RoleRepo roleRepo;

     @Override
    public List<User> getUsers() {
        log.info("Fetching all users {}" );
        return userRepo.findAll() ;
    }
}

When I request http://localhost:8080/api/users, I get wrong data like this

[{"id":5,"name":"Emirhan Ay","username":"emrhn1888","password":"1234","roles":[{"id":1,"name":"ROLE_USER","users":[{"id":5,"name":"Emirhan Ay","username":"emrhn1888","password":"1234","roles":[{"id":1,"name":"ROLE_USER","users":[{"id":5,"name":"Emirhan Ay","username":"emrhn1888","password":"1234","roles":[{"id":1,"name":"ROLE_USER","users":[{"id":5,"name":"Emirhan Ay","username":"emrhn1888","password":"1234","roles":[{"id"}]}]}]}]

But the data saved in the db is like this

Where is my mistake? Thanks in advance for your answers.

CodePudding user response：

You have 'circular dependency'. User has roles, the role has users, etc. You should probably first map entities to DTOS and then maybe add @JsonManagedReference or @JsonBackReference.

Or you can simply put @JsonIgnore on private List<User> users= new ArrayList<User>();