Question

我有一个具有@ManyToMany关系的用户实体和产品实体。我正在尝试将用户选择的产品存储到数据库中。

用户实体：

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

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String username;
    private String password;

    @Transient
    private String passwordConfirm;

    @ManyToMany
    @JoinTable(name = "user_role", joinColumns = @JoinColumn(name = "user_id"), inverseJoinColumns = @JoinColumn(name = "role_id"))
    private Set<Role> roles;

    @ManyToMany(mappedBy = "users")
    private Set<Product> products;    

}

产品实体：

@Entity
@Table(name = "product")
@Getter
@Setter
@ToString
public class Product{

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private String id;
    private String category;
    private String name;

    @ManyToMany
    @JoinTable(name = "user_product", joinColumns = @JoinColumn(name = "product_id"), inverseJoinColumns = @JoinColumn(name = "user_id"))
    private Set<User> users;

}

服务：

@Service
public class ProductServiceImpl implements ProductService{

    @Autowired
    private ProductRepository productRepository;

    @Autowired
    private UserRepository userRepository;

    @Override
    public void save(Product product) {
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
        String currentPrincipalName = authentication.getName();
        User user = userRepository.findByUsername(currentPrincipalName);            
        Set<User> userSet = new HashSet<User>(); 
        userSet.add(user);
        product.setUsers(userSet);                      
        productRepository.save(product);
    }
}

控制器：

@Controller
public class ProductController {

    @Autowired
    private ProductService productService;

    @PostMapping(value = "/product/add", consumes = MediaType.APPLICATION_JSON_VALUE)
    public void add(@RequestBody Product product) {
        productService.save(product);       
    }
}

联接表user_product不允许我与多个用户保存相同的product_id。它将继续删除已经存在的product_id（对于以前保存的user_id），然后将其插入新的user_id，如下所示。

Hibernate: select users0_.product_id as product_id1_5_0_, users0_.user_id as user_id2_5_0_, user1_.id as id1_4_1_, user1_.password as password2_4_1_, user1_.username as username3_4_1_ from user_product users0_ inner join user user1_ on users0_.user_id=user1_.id where users0_.product_id=?       
Hibernate: delete from user_product where product_id=? and user_id=?
Hibernate: insert into user_product (product_id, user_id) values (?, ?)

如何通过使联接表允许product_id和user_id的组合来实现？

我正在使用带有H2数据库的Spring Data JPA，并且确保表列中的关系正确。如果我手动将记录插入表中，则允许但不通过代码。如果我在任何地方都不对，您能纠正我吗？

为什么@ManyToMany关系无法正常工作？

0 个答案: