Hibernate双向多对多 Hibernate双向多对多映射关系配置代码实例
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1、实体类
package com.yl.bean;
import java.io.Serializable;
import java.util.Set;
/**
* 商品实体类
*/
public class Goods implements Serializable {
private Integer id;//商品id
private String goodsName;//商品名
private Double price;//商品价格
private String remark;//备注
private Set<GoodsOrder> orderSet;//商品所属订单
public Goods() {
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getGoodsName() {
return goodsName;
}
public void setGoodsName(String goodsName) {
this.goodsName = goodsName;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public String getRemark() {
return remark;
}
public void setRemark(String remark) {
this.remark = remark;
}
public Set<GoodsOrder> getOrderSet() {
return orderSet;
}
public void setOrderSet(Set<GoodsOrder> orderSet) {
this.orderSet = orderSet;
}
@Override
public String toString() {
return "Goods{" +
"goods_id=" + id +
", goodsName='" + goodsName + '\'' +
", price=" + price +
", remark='" + remark + '\'' +
", orderSet=" + orderSet +
'}';
}
}
package com.yl.bean;
import java.io.Serializable;
import java.util.Set;
/**
* 商品订单实体类
*/
public class GoodsOrder implements Serializable {
private Integer id;//订单id
private String orderNo;//订单编号
private Double price;//订单价格
private Set<Goods> goodsSet;//订单包含的商品
public GoodsOrder() {
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getOrderNo() {
return orderNo;
}
public void setOrderNo(String orderNo) {
this.orderNo = orderNo;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
public Set<Goods> getGoodsSet() {
return goodsSet;
}
public void setGoodsSet(Set<Goods> goodsSet) {
this.goodsSet = goodsSet;
}
@Override
public String toString() {
return "GoodsOrder{" +
"id=" + id +
", orderNo='" + orderNo + '\'' +
", price=" + price +
", goodsSet=" + goodsSet +
'}';
}
}
2、全局配置文件（hibernate.cfg.xml）
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!--数据源配置-->
<property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate?characterEncoding=utf8&serverTimezone=GMT%2B8</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password">123456</property>
<!--显示sql-->
<property name="hibernate.show_sql">true</property>
<!--自动创建表-->
<property name="hibernate.hbm2ddl.auto">update</property>
<!--指定映射配置文件的位置-->
<mapping resource="com/yl/bean/Goods.hbm.xml"></mapping>
<mapping resource="com/yl/bean/GoodsOrder.hbm.xml"></mapping>
</session-factory>
</hibernate-configuration>
3、商品类映射配置文件（Goods.hbm.xml）
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!--配置Goods类-->
<class name="com.yl.bean.Goods" table="t_goods">
<!--主键-->
<id name="id" column="id" type="java.lang.Integer">
<generator class="identity"></generator>
</id>
<property name="goodsName" column="goodsName" type="java.lang.String"></property>
<property name="price" column="price" type="java.lang.Double"></property>
<property name="remark" column="remark"></property>
<!--多对多关系映射-->
<set name="orderSet" table="t_goods_order">
<key column="goods_id"></key>
<many-to-many class="com.yl.bean.GoodsOrder" column="order_id"></many-to-many>
</set>
</class>
</hibernate-mapping>
4、订单类映射配置文件（GoodsOrder.hbm.xml）
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!--配置GoodsOrder类-->
<class name="com.yl.bean.GoodsOrder" table="t_order">
<!--主键-->
<id name="id" column="id" type="java.lang.Integer">
<generator class="identity"></generator>
</id>
<property name="orderNo" column="orderNo" type="java.lang.String"></property>
<property name="price" column="price" type="java.lang.Double"></property>
<!--多对多关系映射-->
<set name="goodsSet" table="t_goods_order">
<key column="order_id"></key>
<many-to-many class="com.yl.bean.Goods" column="goods_id"></many-to-many>
</set>
</class>
</hibernate-mapping>
5、测试
@Test
public void addTest(){
Session session= HibernateUtils.getSession();
Goods goods=new Goods();
goods.setGoodsName("小米");
goods.setPrice(3999.0);
goods.setRemark("为发烧而生");
Goods goods1=new Goods();
goods1.setRemark("中华有为");
goods1.setPrice(3999.0);
goods1.setGoodsName("华为");
GoodsOrder order=new GoodsOrder();
order.setOrderNo("001");
order.setPrice(7998.0);
GoodsOrder order1=new GoodsOrder();
order1.setOrderNo("002");
order1.setPrice(7998.0);
Set<GoodsOrder> orderSet=new HashSet<>();
orderSet.add(order);
orderSet.add(order1);
goods.setOrderSet(orderSet);
goods1.setOrderSet(orderSet);
/* Set<GoodsOrder> orderSet1=new HashSet<>();
orderSet1.add(order1);
goods1.setOrderSet(orderSet1);*/
Set<Goods> goodsSet=new HashSet<>();
goodsSet.add(goods);
goodsSet.add(goods1);
//注意这里，只需要一方关联即可（上面已经关联了，所以不需要再次添加商品集合），两方关联会造成主键重复，报错
// order.setGoodsSet(goodsSet);
// order1.setGoodsSet(goodsSet);
Transaction transaction=session.beginTransaction();
session.save(goods);
session.save(goods1);
session.save(order);
session.save(order1);
transaction.commit();
session.close();
}
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