hibernate中双向多对多的案例（增删查改）

@ManyToMany会生成

@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name="T_ShopCar_Product",//在数据库中会生成一个表T_ShopCar_Product，维护关系
        joinColumns = {@JoinColumn(name="carid")}, //和我的主键保持一致
        inverseJoinColumns = {@JoinColumn(name="pid")} //和ShopCard的主键保持一致
)

需求：购物车和产品（Product,ShopCar）

package com.oracle.bean8;

import lombok.Data;
import org.hibernate.annotations.GenericGenerator;

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

@Entity
@Data
@Table(name="TShopcar")
public class ShopCar {
@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name="uuid",strategy = "uuid")
private String carid;
    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name="T_ShopCar_Product",//在数据库中会生成一个表T_ShopCar_Product
            joinColumns = {@JoinColumn(name="carid")}, //和我的主键保持一致
            inverseJoinColumns = {@JoinColumn(name="pid")} //和ShopCard的主键保持一致
    )
    private List products;


}

package com.oracle.bean8;

import lombok.Data;
import org.hibernate.annotations.GenericGenerator;

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

@Entity
@Data
@Table(name="TProduct")
public class Product {
    @Id
    @GeneratedValue(generator = "uuid")
    @GenericGenerator(name="uuid",strategy = "uuid")
    private String pid;
    private String pcode;
    private String pname;

    @ManyToMany(mappedBy = "products",cascade = CascadeType.ALL)
    private List shopCars;


}

package com.oracle.core;

import com.oracle.bean8.Product;
import com.oracle.bean8.ShopCar;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.util.ArrayList;
import java.util.List;

public class ManyToMany22 {
    private SessionFactory sessionFactory;
    private Session session;

    @Before
    public void begin(){
        Configuration cfg=new Configuration();
        cfg.configure();
        sessionFactory = cfg.buildSessionFactory();
        session = sessionFactory.openSession();
        session.beginTransaction();

    }
    //在购物车里添加商品
@Test
public void tets1(){
    ShopCar car=new ShopCar();


    Product product=new Product();
    product.setPname("aaa");
    product.setPcode("123456");
    Product product2=new Product();
    product2.setPname("bbb");
    product2.setPcode("123456");

    List  productList=new ArrayList<>();
    productList.add(product);
    productList.add(product2);
    car.setProducts(productList);
     session.save(car);


}
//查询购物车的所有商品
@Test
public void query(){
    ShopCar car = session.get(ShopCar.class, "8a8aac9463a5ba420163a5ba4e770000");

    List products = car.getProducts();
    for(Product p:products){
        System.out.println(p.getPname());
    }

}
//在购物车中添加商品
    @Test
    public void add(){
        ShopCar car = session.get(ShopCar.class, "8a8aac9463a5ba420163a5ba4e770000");
        Product product=new Product();
        product.setPname("米兔小飞机");
        car.getProducts().add(product);
       // session.update(car);//update可以省略,hibernate会自动做修改操作
    }
    //把购物车中的某个商品删除，但商品还在，只是在购物车中没有了
    //删除购物车和商品的关系
    public void remove(){
        ShopCar car = session.get(ShopCar.class, "8a8aac9463a5ba420163a5ba4e770000");
       List productList=car.getProducts();
       int index=0;
       for(Product product:productList){
           if(product.getPname().equals("aaa")){
               break;
           }
           index++;
       }

        car.getProducts().remove(index);//删除关系


    }
//清空购物车
    @Test
    public void qingkong(){
        ShopCar car = session.get(ShopCar.class, "8a8aac9463a5ba420163a5ba4e770000");
        car.getProducts().clear();//删除关系


    }
    @After
    public void end(){
        session.getTransaction().commit();
        session.close();
        sessionFactory.close();
    }


}