如何在Spring Boot JPA中获取当前用户的对象

Question

我需要创建购物车。我有一个模型CartItem：

@Entity
@Table(name = "cart_items")
public class CartItem {
 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 private int id;

 @ManyToOne
 @JoinColumn(name = "tour_id")
 private Tour tour;

 @ManyToOne
 @JoinColumn(name = "user_id")
 private User user;

 @Column(name = "order_date")
 private Date date=new Date();
 //getters and setters
}

模型用户：

package com.zaitsava.springboot_touristsite.entity;

import javax.persistence.*;
import java.util.Set;


@Entity
@Table(name = "user")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    @Column(name = "firstname")
    private String firstname;

    @Column(name = "lastname")
    private String lastname;

    @Column(name = "patronymic")
    private String patronymic;

    @Column(name = "email")
    private String email;

    @Column(name = "phone")
    private String phone;

    @Column(name = "password")
    private String password;

    @Column(name = "active")
    private int active;

    @ManyToMany(cascade=CascadeType.ALL)
    @JoinTable(name="user_role", joinColumns=@JoinColumn(name="user_id"),
            inverseJoinColumns=@JoinColumn(name="role_id"))
    private Set<Role> roles;
    //gettes and setters
}

存储库：

public interface CartItemRepository extends JpaRepository<CartItem,Integer> {
    public List<CartItem> findByUser(User user);
}

@Service
public class ShoppingCartService {
    @Autowired
    private CartItemRepository cartItemRepository;

    public List<CartItem> cartItemList(User user){
        return cartItemRepository.findByUser(user);
    };}

现在我正在尝试获取用户并将其传递给查看：

 @GetMapping("/cart")
    public String showCart(Model model,@AuthenticationPrincipal User user){
        //User user = (User) auth.getPrincipal();  try 2
        //User user=(User) SecurityContextHolder.getContext().getAuthentication().getPrincipal(); try 3
        if(user==null) System.out.println("User is null");

        List<CartItem> cartItemList=cartService.cartItemList(user);
        model.addAttribute("cartItems",cartItemList);
        return "user/cart";
    }

在第一种情况下，我得到空值，在情况2和3中：

JAVAlang.ClassCastException:类组织。springframework。安全果心用户详细信息。无法将用户强制转换为com类。扎伊萨瓦。springboot_旅游网站。实体用户（org.springframework.security.core.userdetails.User和com.zaitsava.springboot_touristsite.entity.User位于加载程序“app”的未命名模块中）-

我知道我应该注册AuthenticationPrincipalArgumentResolver，但如何在Spring Boot中注册呢？需要吗？

Answer 1

通过此错误的外观，我看到您正在尝试将org.springframework.security.core.userdetails.User类强制转换为com.zaitsava.springboot_touristsite.entity.User。您可能需要像下面这样明确声明类：

User user=(org.springframework.security.core.userdetails.User) SecurityContextHolder.getContext().getAuthentication().getPrincipal();