treedemo.java

hibernate_tutorial经典教程

package tutorial.dev.tree;

import java.io.Serializable;
import java.sql.Connection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Session;
import net.sf.hibernate.SessionFactory;
import net.sf.hibernate.Transaction;
import net.sf.hibernate.cfg.Configuration;

public class TreeDemo {
	public static void main(String[] args) {
		try {
			new TreeDemo();
		} catch(HibernateException he) {
			he.printStackTrace();
		}
	}
	
	public TreeDemo() throws HibernateException {
		Configuration config = new Configuration();
		// add the classes you want to persist
		// make sure the mapping files are on the classpath
		config.addClass(Friend.class);
		
		SessionFactory sf = config.buildSessionFactory();
	
		Session sess = sf.openSession();
		Transaction tx = null;
		Connection con = null;
		// store the orderlist and all products
		Serializable id = null;
		
		
		Friend a = new Friend("a");
		Friend b = new Friend("b");
		Friend c = new Friend("c");
		Friend d = new Friend("d");
		Friend e = new Friend("e");
		Friend f = new Friend("f");
		Friend g = new Friend("g");
		Friend h = new Friend("h");
		
		
		a.getFriends().add(b);
		a.getFriends().add(c);
		b.getFriends().add(d);
		b.getFriends().add(e);
		b.getFriends().add(f);
		d.getFriends().add(g);
		d.getFriends().add(h);
		
		
		e.getFriends().add(h);
		c.getFriends().add(f);
		
		
		a = new Friend("Root");
		makeFriends(a);
		
		try {
			tx = sess.beginTransaction();
			sess.save(a);
			tx.commit();
		} catch (HibernateException he) {
		    if (tx!=null) tx.rollback();
		    throw he;
		} finally {
		    sess.close();
		}
		Set friends = new HashSet();

		sess = sf.openSession();
		try {
			tx = sess.beginTransaction();
			Friend root = (Friend)sess.get(Friend.class, a.getId());
			friends(root, friends, 2);
			tx.commit();
		} catch (HibernateException he) {
		    if (tx!=null) tx.rollback();
		    throw he;
		} finally {
		    sess.close();
		}
		
		for (Iterator iter = friends.iterator(); iter.hasNext();) {
			Friend friend = (Friend) iter.next();
			System.out.println("Friend: " + friend.getName());
		}
		System.out.println("FriendCount: " + friends.size());
		
	}	
	
	
	protected void friends(Friend root, Set friends, int distance) {
		if (distance > 0) {
			friends.addAll(root.getFriends());
			for (Iterator iter = root.getFriends().iterator(); iter.hasNext();) {
				Friend friend = (Friend) iter.next();
				friends(friend, friends, distance -1);
			}
		}
	}
	private int level = 0;
	private int count = 0;
	protected void makeFriends(Friend root) {
		System.out.println("Level: " + level + " -> " + count);
		if (level < 3) {
			
			for(int i = 0; i < 10; i++) {
				if (Math.random() < 0.6) {
				Friend f = new Friend(root.getName() +"/"+ i);
				count++;
				root.getFriends().add(f);
				level++;
				makeFriends(f);
				level--;
				}
			}
		} else {
			
		}
	
	}
	
	
}