Hibernate的一对多关联关系映射

一个客户可以有多个联系人
比如客户为“中国专业IT社区CSDN”
它所对应的联系人可以为“张总”，“陈总”，等等等等
一对多关系

重点代码：

实体重点代码：

<font color=red >//使用set集合表达一对多关系
	Set<LinkMan> linkmans = new HashSet<LinkMan>();</font>

<font color=red>//表达一对多关系
	private Customer customer;</font>

映射文件重点代码：

	<!-- 配制多对一关系 -->
		<many-to-one name="customer" column="lkm_cust_id" class="Customer"></many-to-one>

<!-- 配置一对多关系 
		 -->
		<set name="linkmans" cascade="save-update" inverse="true">
			<key column="lkm_cust_id"></key>
			<one-to-many class="LinkMan"/>
		</set>

创建客户实体

package cn.zhicheng.domain;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Set;

public class Customer {
	private long cust_id;
	
	private String cust_name;
	private String cust_source;
	private String cust_industry;
	private String cust_level;
	private String cust_phone;
	private String cust_mobile;
	private String cust_linkman;
	
	//使用set集合表达一对多关系
	Set<LinkMan> linkmans = new HashSet<LinkMan>();
	
	public Set<LinkMan> getLinkmans() {
		return linkmans;
	}
	public void setLinkmans(Set<LinkMan> linkmans) {
		this.linkmans = linkmans;
	}
	
	public String toString() {
		return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + "]";
	}
	public long getCust_id() {
		return cust_id;
	}
	public void setCust_id(long cust_id) {
		this.cust_id = cust_id;
	}
	public String getCust_name() {
		return cust_name;
	}
	public void setCust_name(String cust_name) {
		this.cust_name = cust_name;
	}
	public String getCust_source() {
		return cust_source;
	}
	public void setCust_source(String cust_source) {
		this.cust_source = cust_source;
	}
	public String getCust_industry() {
		return cust_industry;
	}
	public void setCust_industry(String cust_industry) {
		this.cust_industry = cust_industry;
	}
	public String getCust_level() {
		return cust_level;
	}
	public void setCust_level(String cust_level) {
		this.cust_level = cust_level;
	}
	public String getCust_phone() {
		return cust_phone;
	}
	public void setCust_phone(String cust_phone) {
		this.cust_phone = cust_phone;
	}
	public String getCust_mobile() {
		return cust_mobile;
	}
	public void setCust_mobile(String cust_mobile) {
		this.cust_mobile = cust_mobile;
	}
	public String getCust_linkman() {
		return cust_linkman;
	}
	public void setCust_linkman(String cust_linkman) {
		this.cust_linkman = cust_linkman;
	}
	
	
}

创建联系人实体

package cn.zhicheng.domain;
public class LinkMan {
	
	private long lkm_id;
	private Character lkm_gender;
	
	private String lkm_name;
	private String lkm_phone;
	private String lkm_mobile;
	private String lkm_email;
	private String lkm_qq;
	private String lkm_position;
	private String lkm_memo;

	//表达一对多关系
	private Customer customer;
	
	public Customer getCustomer() {
		return customer;
	}
	public void setCustomer(Customer customer) {
		this.customer = customer;
	}
	
	
	public long getLkm_id() {
		return lkm_id;
	}
	public void setLkm_id(long lkm_id) {
		this.lkm_id = lkm_id;
	}
	public Character getLkm_gender() {
		return lkm_gender;
	}
	public void setLkm_gender(Character lkm_gender) {
		this.lkm_gender = lkm_gender;
	}
	public String getLkm_name() {
		return lkm_name;
	}
	public void setLkm_name(String lkm_name) {
		this.lkm_name = lkm_name;
	}
	public String getLkm_phone() {
		return lkm_phone;
	}
	public void setLkm_phone(String lkm_phone) {
		this.lkm_phone = lkm_phone;
	}
	public String getLkm_mobile() {
		return lkm_mobile;
	}
	public void setLkm_mobile(String lkm_mobile) {
		this.lkm_mobile = lkm_mobile;
	}
	public String getLkm_email() {
		return lkm_email;
	}
	public void setLkm_email(String lkm_email) {
		this.lkm_email = lkm_email;
	}
	public String getLkm_qq() {
		return lkm_qq;
	}
	public void setLkm_qq(String lkm_qq) {
		this.lkm_qq = lkm_qq;
	}
	public String getLkm_position() {
		return lkm_position;
	}
	public void setLkm_position(String lkm_position) {
		this.lkm_position = lkm_position;
	}
	public String getLkm_memo() {
		return lkm_memo;
	}
	public void setLkm_memo(String lkm_memo) {
		this.lkm_memo = lkm_memo;
	}
	
}

创建映射

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <!-- 配置了包路径，下面就可以直接写类名字了 -->
<hibernate-mapping package="zhicheng.domain">

	<!-- 建立数据库表与类的映射 -->
	<class name="Customer" table="cst_customer">
	
		<!-- 建立类中属性与表中主键的对应 -->
		<id name="cust_id"  column="cust_id">
			<!-- 配置主键生成策略 -->
			<generator class="native"></generator>
		</id>
		
		<!-- 建立类中普通 属性对应表的字段的对应-->
		<!-- property中还有 length type not-null unique 灯属性-->
		<property name="cust_name" column="cust_name" ></property>
		<property name="cust_source" column="cust_source" ></property>
		<property name="cust_industry" column="cust_industry" ></property>
		<property name="cust_level" column="cust_level" ></property>
		<property name="cust_linkman" column="cust_linkman" ></property>
		<property name="cust_phone" column="cust_phone" ></property>
		<property name="cust_mobile" column="cust_mobile" ></property>
		
		<!-- 配置一对多关系 
			name 引用属性名
			colomn  配置数据库表的外键名字
			class 与我关联对象的完整类名 
			
			 配置级联操作
			cascade属性
			save-update 
			delete   (不建议使用,实际开发会很麻烦)
			all
			作用：简化操作，减少代码量
			
			inverse属性 (多的一方默认维护关系)
			true customer不维护关系
			false （默认值） customer维护关系
		 -->
		<set name="linkmans" cascade="save-update" inverse="true">
			
			<key column="lkm_cust_id"></key>
			
			<one-to-many class="LinkMan"/>
		</set>
		
	</class>
</hibernate-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
    <!-- 配置了包路径，下面就可以直接写类名字了 -->
<hibernate-mapping package="cn.zhicheng.domain">
	<class name="LinkMan" table="cst_linkman">
		<id name="lkm_id" column="lkm_id">
			<generator class="native"></generator>
		</id>
		<property name="lkm_gender"></property>
		<property name="lkm_name"></property>
		<property name="lkm_phone"></property>
		<property name="lkm_mobile"></property>
		<property name="lkm_email"></property>
		<property name="lkm_qq"></property>
		<property name="lkm_position"></property>
		<property name="lkm_memo"></property>
		
		<!-- 配制多对一关系 -->
		<!-- 
			name属性名
			column 外键列名字
			class与我关联的完整类名
		 -->
		<many-to-one name="customer" column="lkm_cust_id" class="Customer"></many-to-one>
	</class>
</hibernate-mapping>

级联操作cascade属性与inverse属性

<!-- 配置一对多关系 
		name 引用属性名
		colomn  配置数据库表的外键名字
		class 与我关联对象的完整类名 
		
		 配置级联操作
		cascade属性
		save-update 
		delete   (不建议使用,实际开发会很麻烦)
		all
		作用：简化操作，减少代码量
		
		inverse属性 (多的一方默认维护关系)
		true customer不维护关系
		false （默认值） customer维护关系
	 -->
	<set name="linkmans" cascade="save-update" inverse="true">
		
		<key column="lkm_cust_id"></key>
		
		<one-to-many class="LinkMan"/>
	</set>

将映射添加到核心配置文件

<mapping resource="cn/zhicheng/domain/Customer.hbn.xml"/>
<mapping resource="cn/zhicheng/domain/LinkMan.hbn.xml"/>

编写测试代码

package cn.zhicheng.one2many;

import java.util.Set;

import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;

import cn.itheima.domain.Customer;
import cn.itheima.domain.LinkMan;
import cn.itheima.utils.HibernateUtils;

public class OneToMany {
	@Test
	/*
	 * 一对多表格的操作 
	 * 保存客户以及客户下的练习人
	 */
	public void test(){
		//获得session
		Session session = HibernateUtils.openSession();
		//开启事务
		Transaction tx = session.beginTransaction();
		//执行操作
		Customer customer = new Customer(); //瞬时态
		customer.setCust_name("天狗");
		
		LinkMan linkman1 = new LinkMan();	//瞬时态
		LinkMan linkman2 = new LinkMan();	//瞬时态
		linkman1.setLkm_name("马爸爸");
		linkman2.setLkm_name("张永");
		
		//表达一对多，客户下有多少个练习人
		customer.getLinkmans().add(linkman1);
		customer.getLinkmans().add(linkman2);

		//表达多对一，联系人属于哪个客户
		linkman1.setCustomer(customer);
		linkman2.setCustomer(customer);
		
		
		session.save(customer); 	//持久态
		session.save(linkman1);
		session.save(linkman2);
		//提交事务
		tx.commit();
		//释放资源
		session.close();
	}
	
	@Test
	//为客户添加联系人
	public void test2(){
		//获得session
		Session session = HibernateUtils.openSession();
		//开启事务
		Transaction tx = session.beginTransaction();
		//执行操作
		
		Customer customer = session.get(Customer.class, 1l);
		
		LinkMan man1 = new LinkMan();
		man1.setLkm_name("新增联系人");
		LinkMan man2 = new LinkMan();
		man2.setLkm_name("新增联系人2");
		
		customer.getLinkmans().add(man1);
		customer.getLinkmans().add(man2);
		
		man1.setCustomer(customer);
		man2.setCustomer(customer);
		
		session.save(customer);
		session.save(man1);
		session.save(man2);
		
		//往客户添加联系人
		//变成持久态
		//提交事务
		tx.commit();
		//释放资源
		session.close();
	}
	
	@Test
	//为客户删除联系人
	public void test3(){
		//获得session
		Session session = HibernateUtils.openSession();
		//开启事务
		Transaction tx = session.beginTransaction();
		//执行操作
		Customer customer = session.get(Customer.class, 1l);
		LinkMan linkMan = session.get(LinkMan.class, 4l);
		
		customer.getLinkmans().remove(linkMan);
		linkMan.setCustomer(null);
		
		//提交事务
		tx.commit();
		//释放资源
		session.close();
	}
	
	@Test
	/*
	 * 级联操作
	 * 保存客户已经客户下的练习人
	 */
	public void test4(){
		//获得session
		Session session = HibernateUtils.openSession();
		//开启事务
		Transaction tx = session.beginTransaction();
		//执行操作
		Customer customer = new Customer(); //瞬时态
		customer.setCust_name("天狗");
		
		LinkMan linkman1 = new LinkMan();	//瞬时态
		linkman1.setLkm_name("级联操作添加");
		LinkMan linkman2 = new LinkMan();	//瞬时态
		linkman2.setLkm_name("级联操作添加2");
		
		//表达一对多，客户下有多少个练习人
		customer.getLinkmans().add(linkman1);
		customer.getLinkmans().add(linkman2);

		//表达多对一，联系人属于哪个客户
		linkman1.setCustomer(customer);
		linkman2.setCustomer(customer);
		
		
		session.save(customer); 	//持久态
		//提交事务
		tx.commit();
		//释放资源
		session.close();
	}
	
	@Test
	/*
	 * 级联操作
	 * 删除客户以及客户下的练习人
	 */
	public void test5(){
		//获得session
		Session session = HibernateUtils.openSession();
		//开启事务
		Transaction tx = session.beginTransaction();
		//执行操作
		Customer customer = session.get(Customer.class, 1l);
		session.delete(customer);
		//提交事务
		tx.commit();
		//释放资源
		session.close();
	}
	
}