hibernate多对多映射

一、创建实体类

 

package com.wr.hibernate.entity;

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

public class Person {

	private int id;
	private String name;
	private Set<Role> roles = new HashSet<Role>();

	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;
	}

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

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

}

 

package com.wr.hibernate.entity;

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

public class Role {
	
	private int id;
	private String name;
	private Set<Person> persons = new HashSet<Person>();

	public Set<Person> getPersons() {
		return persons;
	}

	public void setPersons(Set<Person> persons) {
		this.persons = persons;
	}

	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;
	}


}

 

二、创建POJO映射

 

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

<hibernate-mapping package="com.wr.hibernate.entity">

	<class name="Person" table="person">

		<id name="id" type="java.lang.Integer">
			<column name="person_id" />
			<!-- 指定主键的生成方式, native: 使用数据库本地方式 -->
			<generator class="native" />
		</id>

		<property name="name" type="java.lang.String">
			<column name="person_name" />
		</property>
		
		<!-- 指定中间表person_role -->
		<set name="roles" table="person_role">
			<key column="person_id"></key>
			<many-to-many class="Role" column="role_id"></many-to-many>
		</set>
		
		
	</class>

</hibernate-mapping>

 

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

<hibernate-mapping package="com.wr.hibernate.entity">

	<class name="Role" table="role">

		<id name="id" type="java.lang.Integer">
			<column name="role_id" />
			<!-- 指定主键的生成方式, native: 使用数据库本地方式 -->
			<generator class="native" />
		</id>

		<property name="name" type="java.lang.String">
			<column name="role_name" />
		</property>

		<!-- 指定中间表person_role -->
		<set name="persons" table="person_role" inverse="true">
			<key column="role_id"></key> 
			<many-to-many class="Person" column="person_id"></many-to-many>
		</set>
	</class>

</hibernate-mapping>