[英]JPA Repository.findById() returns null but the value is exist on db
[英]JPA Repository Findbyid Returns Repeated List
我的 retriveUser 方法有问题。 当我运行 finbyid 方法时,它返回相同的重复值。 您可以在下面看到我的存储库、用户和 userService 类以及结果。
[![findbyid 方法结果][1]][1]
我的用户存储库 Class
package io.javabrains.springsecurity.jpa;
import io.javabrains.*;
import java.util.Optional;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import io.javabrains.springsecurity.jpa.models.User;
@Repository
public interface UserRepository extends JpaRepository<User, Integer> {
Optional<User> findByUserName(String userName);
}
我的用户 Class
@Entity
@Table(name="app_user")
public class User implements Serializable {
@Id
@GeneratedValue(strategy =GenerationType.IDENTITY)
private int id;
private String userName;
private String password;
private boolean active;
private String role;
private String city;
public User(String userName, boolean active, String role, String city) {
super();
this.userName = userName;
this.active = active;
this.role = role;
this.city = city;
}
@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
@JoinTable(name = "user_cities", joinColumns = @JoinColumn(name = "user_id", referencedColumnName = "id"),
inverseJoinColumns = @JoinColumn(name = "city_id", referencedColumnName = "id"))
private Collection<UserCity> usercities = new ArrayList<UserCity>() ;
public Collection<UserCity> getUsercities() {
return usercities;
}
public void setUsercities(Collection<UserCity> usercities) {
this.usercities = usercities;
}
public User() {}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public boolean isActive() {
return active;
}
public void setActive(boolean active) {
this.active = active;
}
public String getRole() {
return role;
}
public void setRole(String role) {
this.role = role;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
}
我的服务 Class
@RestController
public class HomeResource {
@Autowired
private BCryptPasswordEncoder bcryptPasswordEncoder;
@Autowired
private WeatherService weatherService;
@Autowired
private CityRepository cityRepository;
@Autowired
private UserRepository userRepo;
@GetMapping("/")
public String home() {
return ("<h1>Welcome</h1>");
}
@GetMapping("/user")
public String user() {
return ("Welcome User");
}
@GetMapping("/admin")
public String admin() {
return ("<h1>Welcome Admin</h1>");
}
@GetMapping("/getCities")
public List<UserCity> getCities()
{
return cityRepository.findAll();
}
@GetMapping("/users/{id}")
public ResponseEntity<User> retriveUser(@PathVariable int id){
Optional<User> a=userRepo.findById(id);
return new ResponseEntity<User>(a.get(),HttpStatus.OK);
}
在此先感谢您的帮助。
重复值是来自User
object 中的usercities
集合的嵌套用户。
用户 ( id: 1
) 有一个usercities
集合,其中包含一个 UserCity object ( cityName: 'bursa'
and users
包含相同的用户 ( id: 1
))。 因此,递归地显示用户( id: 1
)。
您可以将 @JsonIgnore 注释添加到您的属性( users
中的 usercities 或usercities
中的用户)以减少递归。
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