@GetMapping 不会在用户名下显示 CreditCards。 @PostMapping 不会为用户创建新卡，它只会更新它

Question

我的用户 Class 如下所示：

@Entity
@Table(name = "Users")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "userID")
    private Integer userID;
    @Column(name = "username",nullable = false, unique = true)
    private String username;
    @Column(name = "password")
    private String password;
    @Column(name = "name")
    private String name;
    @Column(name = "address")
    private String address;
    @Column(name = "email")
    private String email;

    @OneToMany(mappedBy = "user", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
        private List<CreditCard> creditCard;

//Constructor, Getters and Setters

信用卡Class看起来：

@Entity
@Table(name = "CreditCards")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class CreditCard {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "cardID", nullable = false)
    private Integer cardID;
    @Column(name = "cardName")
    private String cardName;
    @Column(name = "cardNumber")
    private BigInteger cardNumber;
    @Column(name = "expirationDate")
    private Integer expirationDate;
    @Column(name = "securityCode")
    private Integer securityCode;

    @ManyToOne(fetch = FetchType.EAGER, optional = false)
    @JoinColumn(name = "user_id", nullable = false)
    @JsonIgnore
    private User user;

//Constructor, Getters and Setters

信用卡资源：

@RestController
@RequestMapping("/geektext/users")
class CreditCardResource {

    @Autowired
    CreditCardRepository cardsRepository;

    @Autowired
    UserRepository userRepository;

    //Displays CreditCard By Username Search
    @GetMapping("/{username}/cards")
    public Optional<CreditCard> getCardsByUsername(@PathVariable String username) throws NotFoundException {
        if (!userRepository.findByUsername(username).isPresent()){
            throw new NotFoundException("User '" + username + "' not found");
        }
        return cardsRepository.findById(userRepository.findByUsername(username).get().getUserID());
    }

    //Creates New Card for User
    @PostMapping("/{userID}/cards")
    public CreditCard loadCard(@PathVariable String userID, @RequestBody CreditCard creditCard) throws NotFoundException {

        return userRepository.findByUsername(userID).map(user -> {creditCard.setUser(user);
        return cardsRepository.save(creditCard);
        }).orElseThrow(() -> new NotFoundException("User '" + userID + "' not found"));

    }
}

还有一个 UserResource.java 、UserRepository（接口）和 CreditCardRepository），但这些不会影响我遇到的问题。请问如何修复在 url 上为传递用户名的用户获取卡片列表的问题。用户如何创建新的/多个信用卡而不是更新他拥有的信用卡。

Answer 1

您正在尝试使用您的用户 ID 获取信用卡

return cardsRepository.findById(userRepository.findByUsername(username).get().getUserID());

相反，您可以按用户搜索您的信用卡。为此，您应该在信用卡存储库界面中创建一个方法。

List<CreditCard> findByUser(User user);

然后从你的控制器调用这个方法

return cardsRepository.findByUser(userRepository.findByUsername(username).get())

post方法也有类似的问题。您正在尝试通过用户名获取用户，但传递的是用户 ID。您还可以将用户设置为您的新信用卡，但不会向您的用户添加新信用卡。（并将用户 class 中的信用卡变量名称更改为 creditCards）
```
return userRepository.findByUsername(userID).map(user -> {creditCard.setUser(user);
return cardsRepository.save(creditCard);
}).orElseThrow(() -> new NotFoundException("User '" + userID + "' not found"));
```
这样会好很多。自己测试一下，写错了再改
```
User user = userRepository.findById(userID);
user.getCreditCards().add(creditCard);
creditCard.setUser(user);
userRepository.save(user);
```
NotFoundException 我想你可以自己处理。

Answer 2

更新：我必须为每张信用卡创建一个 ID，因为如果在创建每张新信用卡时都分配了相同的 ID，那么程序就会像我和试图成为的信用卡一样对待它已更新。

@GetMapping 不会在用户名下显示 CreditCards。 @PostMapping 不会为用户创建新卡，它只会更新它

@GetMapping doesn't display CreditCards under username. @PostMapping doesn't create a new card for user, it only updates it

spring

one-to-many

many-to-one

spring-data-jpa

spring-boot