Hibernate多对多+级联操作

1、写一个实体类

package hibernate;
import java.util.HashSet;
import java.util.Set;
public class User {
	private Integer user_id;
	private String user_name;
	private String user_password;
	
	private Set<Role> roles = new HashSet<Role>();
	
	public Set<Role> getRoles() {
		return roles;
	}
	public void setRoles(Set<Role> roles) {
		this.roles = roles;
	}
	public Integer getUser_id() {
		return user_id;
	}
	public void setUser_id(Integer user_id) {
		this.user_id = user_id;
	}
	public String getUser_name() {
		return user_name;
	}
	public void setUser_name(String user_name) {
		this.user_name = user_name;
	}
	public String getUser_password() {
		return user_password;
	}
	public void setUser_password(String user_password) {
		this.user_password = user_password;
	}	
}

2、再写一个实体类

package hibernate;
import java.util.HashSet;
import java.util.Set;
public class Role {
	private Integer role_id;
	private String role_name;
	private String role_memo;
	
	private Set<User> users = new HashSet<User>();
	
	public Set<User> getUsers() {
		return users;
	}
	public void setUsers(Set<User> users) {
		this.users = users;
	}
	public Integer getRole_id() {
		return role_id;
	}
	public void setRole_id(Integer role_id) {
		this.role_id = role_id;
	}
	public String getRole_name() {
		return role_name;
	}
	public void setRole_name(String role_name) {
		this.role_name = role_name;
	}
	public String getRole_memo() {
		return role_memo;
	}
	public void setRole_memo(String role_memo) {
		this.role_memo = role_memo;
	}	
}

3、类的映射关系xml

<?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">
	
<hibernate-mapping>
	<class name="hibernate.User" table="user">
		<id name="user_id" column="user_id">
			<generator class="native"></generator>
		</id>
		<property name="user_name" column="user_name"></property>
		<property name="user_password" column="user_password"></property>
		<set name="roles" table="user_role" cascade="save-update,delete">
			<!-- column是外键名称 -->
			<key column="userid"></key>
			<many-to-many class="hibernate.Role" column="roleid"></many-to-many>
		</set>
	</class>
</hibernate-mapping>

4、另一个类的映射关系xml

<?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">
<hibernate-mapping>
	<class name="hibernate.Role" table="role">
		<id name="role_id" column="role_id">
			<generator class="native"></generator>
		</id>
		<property name="role_name" column="role_name"></property>
		<property name="role_memo" column="role_memo"></property>
		
		<set name="users" table="user_role">
			<!-- column是外键名称 -->
			<key column="roleid"></key>
			<many-to-many class="hibernate.User" column="userid"></many-to-many>
		</set>
	</class>
</hibernate-mapping>

5、核心配置文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
	"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
	"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
	<session-factory>
		<!-- 1、配置数据库信息 -->
		<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="hibernate.connection.url">jdbc:mysql:///hibernate</property>
		<property name="hibernate.connection.username">root</property>
		<property name="hibernate.connection.password">root</property>
		
		<!-- 2、配置hibernate信息 可选的-->
		<!-- 输出底层sql语句 -->
		<property name="hibernate.show_sql">true</property>
		<!-- 对底层sql语句格式化 -->
		<property name="hibernate.format_sql">true</property>
		<!-- hibernate帮创建表
			update：如果已经有表，更新，如果没有，创建-->
		 <property name="hibernate.hbm2ddl.auto">update</property>
		 <!-- 配置数据库方言
		 	 让hibernate识别不同数据库语句-->
		 <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
		 
		 <!-- 3、把映射文件放到核心配置文件中 -->
		 <mapping resource="hibernate/User.hbm.xml"></mapping>
		 <mapping resource="hibernate/Role.hbm.xml"></mapping>
	</session-factory>
</hibernate-configuration>

6、测试文件

package hibernate;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.junit.Test;
public class TestHibernate {
	@Test
	public void test()
	{
		//1、加载hibernate核心配置文件
		Configuration cfg = new Configuration();
		cfg.configure();
		//2、创建SessionFactory对象
		//读取核心配置文件，创建sessionFactory
		//根据映射关系创建表
		SessionFactory sessionFacroty =  cfg.buildSessionFactory();
		//3、创建session对象
		//类似于创建连接
		Session session = sessionFacroty.openSession();
		//4、开启事务
		org.hibernate.Transaction tx = session.beginTransaction();
		//5、写具体crud操作
		User u1 = new User();
		u1.setUser_name("lucy");
		u1.setUser_password("123");
		
		User u2 = new User();
		u2.setUser_name("mary");
		u2.setUser_password("456");
		
		Role r1 = new Role();
		r1.setRole_memo("总经理");
		r1.setRole_name("总经理");
		
		Role r2 = new Role();
		r2.setRole_memo("秘书");
		r2.setRole_name("秘书");
		
		Role r3 = new Role();
		r3.setRole_memo("保安");
		r3.setRole_name("保安");
		
		//u1 -- r1/r2
		//u2 -- r2/r3
		
		u1.getRoles().add(r1);
		u1.getRoles().add(r2);
		u2.getRoles().add(r2);
		u2.getRoles().add(r3);
		
		session.save(u1);
		session.save(u2);
		//6、提交事务
		tx.commit();
		//7、关闭资源
		session.close();
		sessionFacroty.close();	
	}
}