package com.bjsxt.hibernate;

import java.util.HashSet;

import java.util.Set;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.OneToMany;

import javax.persistence.Table;

@Entity

@Table(name="t_group")

public class Group {

	private int id;

	private String name;

	private Set<User> users = new HashSet<User>();

	@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;

	}

	@OneToMany(mappedBy="group")

	public Set<User> getUsers() {

		return users;

	}

	public void setUsers(Set<User> users) {

		this.users = users;

	}

}

package com.bjsxt.hibernate;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.ManyToOne;

import javax.persistence.Table;

@Entity

@Table(name="t_user")

public class User {

	private int id;

	private String name;

	private Group group;

	@ManyToOne

	public Group getGroup() {

		return group;

	}

	public void setGroup(Group group) {

		this.group = group;

	}

	@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;

	}

}

<?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/hibernate</property>

        <property name="connection.username">root</property>

        <property name="connection.password">linda0213</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>

        <!-- Drop and re-create the database schema on startup

        <property name="hbm2ddl.auto">update</property>

		 -->

         <mapping class="com.bjsxt.hibernate.Group"/>

		<mapping class="com.bjsxt.hibernate.User"/>

		 <!--  

		<mapping resource="com/bjsxt/hibernate/Group.hbm.xml"/>

		 <mapping resource="com/bjsxt/hibernate/User.hbm.xml"/> -->

    </session-factory>

</hibernate-configuration>

<?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>

	<class name="com.bjsxt.hibernate.Group" table="t_group">

		<id name="id">

			<generator class="native"></generator>

		</id>

		<property name="name"></property>

		<set name="users">

			<key column="groupId"></key>

			<one-to-many class="com.bjsxt.hibernate.User"/>

		</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>

	<class name="com.bjsxt.hibernate.User" table="t_user">

		<id name="id">

			<generator class="native"></generator>

		</id>

		<property name="name"></property>

		<many-to-one name="group" column="groupId"></many-to-one>

    </class>

</hibernate-mapping>