hibernate---树状映射

package com.bjsxt.hibernate;

import java.util.HashSet;
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.ManyToOne;
import javax.persistence.OneToMany;

@Entity
public class Org {
	private int id;
	private String name;
	private Set<Org> children = new HashSet<Org>();
	private Org parent;
	@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(cascade=CascadeType.ALL, mappedBy="parent")
	public Set<Org> getChildren() {
		return children;
	}
	public void setChildren(Set<Org> children) {
		this.children = children;
	}
	
	@ManyToOne
	@JoinColumn(name="parent_id")
	public Org getParent() {
		return parent;
	}
	public void setParent(Org parent) {
		this.parent = parent;
	}
}

<?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 resource="com/bjsxt/hibernate/Group.hbm.xml"/>
		 <mapping resource="com/bjsxt/hibernate/User.hbm.xml"/>
		 -->
		  <mapping class="com.bjsxt.hibernate.Org"/>
        
		
    </session-factory>

</hibernate-configuration>

package com.bjsxt.hibernate;

import java.util.Map;

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;

public class HibernateTreeTest {
	private static SessionFactory sessionFactory;
	
	@BeforeClass
	public static void beforeClass() {
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
		sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
	}
	@AfterClass
	public static void afterClass() {
		sessionFactory.close();
	}
	
	@Test
	public void testSave() {
		Org o = new Org();
		o.setName("总公司");
		Org o1 = new Org();
		o1.setName("分公司1");
		Org o2 = new Org();
		o2.setName("分公司2");
		Org o11 = new Org();
		o11.setName("分公司1下部门1");
		Org o12 = new Org();
		o12.setName("分公司1下部门2");
		
		o.getChildren().add(o1);
		o.getChildren().add(o2);
		o1.getChildren().add(o11);
		o1.getChildren().add(o12);
		o11.setParent(o1);
		o12.setParent(o1);
		o1.setParent(o);
		o2.setParent(o);
				
		
		Session session = sessionFactory.openSession();
		session.beginTransaction();
		session.save(o);
	
		session.getTransaction().commit();
		session.close();
	}
	@Test
	public void testLoad() {
		testSave();
		Session session = sessionFactory.openSession();
		session.beginTransaction();
		Org o = (Org)session.load(Org.class, 1);
		print(o, 0);
		session.getTransaction().commit();
		session.close();
		
	}
	
	private void print(Org o, int level) {
		String preStr = "";
		for(int i=0; i<level; i++) {
			preStr += "----";
		}
		System.out.println(preStr + o.getName());
		for(Org child : o.getChildren()) {
			print(child, level+1);
		}
	}
	@Test
	public void testSchemaExport() {
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
	}
	
	
	public static void main(String[] args) {
		beforeClass();
	}
}