9.Hibernate的多对多单向关联映射

hibernate多对多关联映射(单向User---->Role)

具体映射方式：
    <set name="roles" table="t_user_role">
        <key column="userid"/>
        <many-to-many class="Role" column="roleid"/>
    </set>

 

一：实体类：

package com.tao.hibernate.many2many;

public class Role {
	private Integer id;
	private String name;

	public Role() {
		super();
	}

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

}

 

package com.tao.hibernate.many2many;

import java.util.Set;

public class User {
	private Integer id;
	private String name;
	private Set<Role> roles;

	public User() {
		super();
	}

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Set<Role> getRoles() {
		return roles;
	}

	public void setRoles(Set<Role> roles) {
		this.roles = roles;
	}
}

 

二：映射文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.tao.hibernate.many2many">
	<class name="Role" table="t_role">
		<id name="id" column="id" type="integer">
			<generator class="native">
			</generator>
		</id>
		<property name="name" column="name" />
		
	</class>
</hibernate-mapping>

 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.tao.hibernate.many2many"
	auto-import="false">
	<class name="User" table="t_user">
		<id name="id" column="id" type="integer">
			<generator class="native">
			</generator>
		</id>
		<property name="name" column="name" />
		<set name="roles" table="t_user_role" cascade="all">
			<key column="userId" />
			<many-to-many class="Role" column="roleId" />
		</set>
	</class>
</hibernate-mapping>

 

三：测试类：

package com.tao.hibernate.many2many;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

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

import com.tao.hibernate.HibernateUtils;

public class TestMain {
	Session session = HibernateUtils.getFactory().openSession();

	@Test
	public void testSave() {
		User u1 = new User();
		u1.setName("u1");
		User u2 = new User();
		u2.setName("u2");
		User u3 = new User();
		u3.setName("u3");

		Role r1 = new Role();
		r1.setName("admin");
		Role r2 = new Role();
		r2.setName("guest");

		Set<Role> roles1 = new HashSet<Role>();
		roles1.add(r1);
		Set<Role> roles2 = new HashSet<Role>();
		roles2.add(r2);
		Set<Role> roles3 = new HashSet<Role>();
		roles3.add(r1);
		roles3.add(r2);

		u1.setRoles(roles1);
		u2.setRoles(roles2);
		u3.setRoles(roles3);

		Transaction ts = session.beginTransaction();
		ts.begin();
		session.save(u1);
		session.save(u2);
		session.save(u3);
		ts.commit();
	}

	@Test
	public void testLoad() {
		Session session = HibernateUtils.getFactory().openSession();
		User u1 = (User) session.load(User.class, 1);
		System.out.println(u1.getName());
		for (Iterator<Role> iter = u1.getRoles().iterator(); iter.hasNext();) {
			System.out.println(iter.next().getName());
		}
	}

}