Spring JPA: Why is my list of users empty?

Question

H2 TABLE: USERS

 | USER_ID | USER_NAME | USER_PASSWORD | USER_RIGHTS |  
 -----------------------------------------------------
 |    1    |  rooter   |     123456    |    ROOT     |  

@Entity
@Getter
@Setter
@Table(name = "USERS")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "user_id")
    private Long userId;
    @Column(name = "user_name")
    private String userName;
    @Column(name = "user_password")
    private String userPassword;
    @Column(name = "user_rights")
    private String userRights;
    // equals() and toString()
}

public interface UserRepository extends JpaRepository<User, Long> {
    User findByUserName(String userName);
    User findByUserId(Long id);
}

@RestController
@RequestMapping("/user")
public class UsersApi {
    private final UserRepository userRepository;

    public UsersApi(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    @GetMapping("/test")
    public List<User> test(String name, Long id) {
        List<User> response = new LinkedList<>();
        response.add(userRepository.findByUserName(name));
        response.add(userRepository.findByUserId(id));
        return response;
    }
}

When I visit /user/test?name=rooter&id=1 it will response with:

[
    null,
    {
        "userId":1,
        "userName":"root",
        "userPassword":"123456",
        "userRights":"ROOTER"
    }
]

Why the method findByUserName(String userName) cannot find the data?

Answer 1

In the response array the username of the user with id 1 is root and the provided request parameter for finding a user by its username is rooter. So I would recommend you to check if the userName is root instead of rooter.