hibernate 多对多注解配置

1、在公司一个员工对应多个部门，一个部门对应多个员工，因此部门与员工之间就是多对多的关系。

Person类的代码如下：

package com.mr.cheng.bean;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.ManyToOne;

import org.hibernate.annotations.Cascade;

@Entity
public class Person {
	private Integer id;
	private String name;
	private int age;
	private double price;
	private Set<Dept> depts;
	/**
	 * 多对多由一方来完成，
	 */
	@ManyToMany(cascade=CascadeType.ALL)
	@JoinTable(name="personDeptTable",
			/**
			 * 这一方的Id
			 */
			joinColumns={@JoinColumn(name="personId")},
			/**
			 * 反转的另外一段的列名,既对方一张表的Id
			 * @return
			 */
			inverseJoinColumns={@JoinColumn(name="deptId")}
			 )
	public Set<Dept> getDepts() {
		return depts;
	}
	@Override
	public String toString() {
		return "Person [id=" + id + ", name=" + name + ", age=" + age
				+ ", price=" + price + ", depts=" + depts + "]";
	}
	public void setDepts(Set<Dept> depts) {
		this.depts = depts;
	}
	@Id
	@GeneratedValue
	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 int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public double getPrice() {
		return price;
	}
	public void setPrice(double price) {
		this.price = price;
	}
}

　　Dept类的代码如下：

package com.mr.cheng.bean;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name="deptTable")
public class Dept {
	private int id;
	private String name;
	private Set<Person>persons;
	@Id@GeneratedValue
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@ManyToMany
	(mappedBy="depts")
	public Set<Person> getPersons() {
		return persons;
	}
	public void setPersons(Set<Person> persons) {
		this.persons = persons;
	}
}

2、hibernate.hbm.xml配置如下：

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>


	<property name="connection.driver_class">
		com.mysql.jdbc.Driver
	</property>
	<property name="connection.url">
		jdbc:mysql://localhost/test
	</property>
	<property name="connection.username">root</property>
	<property name="connection.password">root</property>
	<property name="dialect">
		org.hibernate.dialect.MySQLDialect
	</property>
	<!--
		<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
		<property name="connection.url">jdbc:oracle:thin:@localhost:1521:SXT</property>
		<property name="connection.username">scott</property>
		<property name="connection.password">tiger</property>
		<property name="dialect">org.hibernate.dialect.OracleDialect</property>
	-->

	<!-- JDBC connection pool (use the built-in) -->
	<property name="connection.pool_size">1</property>



	<!-- Enable Hibernate's automatic session context management -->
	<property name="current_session_context_class">thread</property>

	<!-- Disable the second-level cache  -->
	<property name="cache.provider_class">
		org.hibernate.cache.NoCacheProvider
	</property>

	<!-- Echo all executed SQL to stdout -->
	<property name="show_sql">true</property>
	<property name="format_sql">true</property>
	<mapping class="com.mr.cheng.bean.Dept" />
	<mapping class="com.mr.cheng.bean.Person" />

</session-factory>

</hibernate-configuration>

　　

3、测试代码如下：

package com.mr.cheng.test;

import java.util.Date;
import java.util.HashSet;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

import com.mr.cheng.bean.Dept;
import com.mr.cheng.bean.Person;


public class HibernateTest {
	private static SessionFactory sessionFactory;
	
	//@BeforeClass
	public static void beforeClass() {
			sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
	}
	//@AfterClass
	public static void afterClass() {
		sessionFactory.close();
	}
	
	
	
	@Test
	public void testSchemaExport() {
		new SchemaExport(new AnnotationConfiguration().configure()).create(true, true);
	}
	
	public static void main(String[] args) {
		beforeClass();
	}
	/**
	 * 多对多单向
	 */
	@Test
	public void testManyToManyAddPersonAndDept(){
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
		sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
		Session session = sessionFactory.openSession();
		session.beginTransaction();
		Dept dept = new Dept();
		dept.setName("财务部");
		Dept dept1 = new Dept();
		dept1.setName("财务部");
		Person person = new Person();
		person.setName("A111");
		person.setAge(33);
		person.setPrice(33);
		Person person1 = new Person();
		person1.setName("A111");
		person1.setAge(33);
		person1.setPrice(33);
		person.setDepts(new HashSet<Dept>());
		person1.setDepts(new HashSet<Dept>());
		person.getDepts().add(dept);
		person.getDepts().add(dept1);
		
		
		person1.getDepts().add(dept);
		person1.getDepts().add(dept1);
		
		session.save(person1);
		session.save(person);
		/*session.save(dept1);
		session.save(dept);*/
		session.getTransaction().commit();
	}
	/**
	 * 多对多单向查询 Person 一方
	 */
	@Test
	public void testManyToManyQueryPerson(){
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, false);
		sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
		Session session = sessionFactory.openSession();
		session.beginTransaction();
		Person p = (Person) session.load(Person.class, 1);
		System.out.println(p.getDepts());
		session.getTransaction().commit();
	}
	/**
	 * 多对多单向查询 Dept 一方
	 */
	@Test
	public void testManyToManyQueryDept(){
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, false);
		sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
		Session session = sessionFactory.openSession();
		session.beginTransaction();
		Dept dept = (Dept) session.load(Dept.class, 1);
		System.out.println(dept.getPersons());
		session.getTransaction().commit();
	}
	@Test
	public void testManyToManyAddPersonAndDept1(){
		sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
		Session session = sessionFactory.openSession();
		session.beginTransaction();
		Dept dept = new Dept();
		dept.setName("财务部");
		Dept dept1 = new Dept();
		dept1.setName("财务部");
		Person person = new Person();
		person.setName("A111");
		person.setAge(33);
		person.setPrice(33);
		Person person1 = new Person();
		person1.setName("A111");
		person1.setAge(33);
		person1.setPrice(33);
		
		dept1.setPersons(new HashSet());
		dept.setPersons(new HashSet());
		
		dept1.getPersons().add(person1);
		dept1.getPersons().add(person);
		
		
	/*	session.save(person1);
		session.save(person);*/
		session.save(dept1);
		session.save(dept);
		session.getTransaction().commit();
	}
}