lazydevdemo.java

hibernate_tutorial经典教程

package tutorial.dev.lazy;

import java.util.HashSet;
import java.util.Iterator;

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

public class LazyDevDemo {
	public static void main(String[] args) {
		try {
			new LazyDevDemo();
		} catch(HibernateException he) {
			he.printStackTrace();
		}
	}
	
	public LazyDevDemo() throws HibernateException {
		Configuration config = new Configuration();
		// add the classes you want to persist
		// make sure the mapping files are on the classpath
		config.addClass(InLazySet.class);
		config.addClass(WithLazySet.class);
		SessionFactory sf = config.buildSessionFactory();
	
		
		for (int i = 0; i < 100 ; i++) {
		Session sess = sf.openSession();
		Transaction tx = null;
		// store the orderlist and all products
		
		WithLazySet l = new WithLazySet();
		l.setLazy(new HashSet());
		l.getLazy().add(new InLazySet());
		l.getLazy().add(new InLazySet());
		l.getLazy().add(new InLazySet());
		l.getLazy().add(new InLazySet());
		l.getLazy().add(new InLazySet());
		l.getLazy().add(new InLazySet());
		try {
			tx = sess.beginTransaction();
			sess.save(l);
			tx.commit();
		} catch (HibernateException e) {
		    if (tx!=null) tx.rollback();
		    throw e;
		} 
		finally {
		    sess.close();
		}
		System.out.println("Wrote dummy data");
		/*
		sess = sf.openSession();
		tx = null;
		try {
			tx = sess.beginTransaction();
			System.out.println("Loading and accessing in the same session");
			WithLazySet l2 = (WithLazySet) sess.get(WithLazySet.class, l.getId());
			for (Iterator iter = l2.getLazy().iterator(); iter.hasNext();) {
				InLazySet lazy = (InLazySet) iter.next();
				System.out.println("loaded: " + lazy.getId());
			}
			tx.commit();
		} catch (HibernateException e) {
		    if (tx!=null) tx.rollback();
		    throw e;
		}
		finally {
		    sess.close();
		}
		*/
		/*
		System.out.println("Loading, closing and accessing");
		sess = sf.openSession();
		tx = null;
		WithLazySet l3 = null;
		try {
			tx = sess.beginTransaction();
			l3 = (WithLazySet) sess.get(WithLazySet.class, l.getId());
		
			tx.commit();
		} catch (HibernateException e) {
		    if (tx!=null) tx.rollback();
		    throw e;
		}
		finally {
		    sess.close();
		}
		// should trow exception
		try {
			for (Iterator iter = l3.getLazy().iterator(); iter.hasNext();) {
				InLazySet lazy = (InLazySet) iter.next();
				System.out.println("loaded: " + lazy.getId());
			}
			// getting ugly...junit would not have been that bad ;-)
			throw new RuntimeException("must not be here");
		} catch(LazyInitializationException lie) {
			System.out.println("Caught expected lazyinit exception");
		}
		*/
		// with reatach
		System.out.println("Reatach and accessing");

		System.out.println("load L4");
		sess = sf.openSession();
		tx = null;

		WithLazySet l4 = null;
		try {
			tx = sess.beginTransaction();
			l4 = (WithLazySet) sess.get(WithLazySet.class, l.getId());
		
			tx.commit();
		} catch (HibernateException e) {
		    if (tx!=null) tx.rollback();
		    throw e;
		}
		finally {
		    sess.close();
		}

		System.out.println("reatach");
		sess = sf.openSession();
		tx = null;
		try {
			tx = sess.beginTransaction();
			//sess.lock(l4, LockMode.NONE);
			sess.update(l4);
			System.out.println("locked");
			for (Iterator iter = l4.getLazy().iterator(); iter.hasNext();) {
				InLazySet lazy = (InLazySet) iter.next();
				System.out.println("loaded: " + lazy.getId());
			}
			
			
			tx.commit();
		} catch (HibernateException e) {
		    if (tx!=null) tx.rollback();
		    throw e;
		}
		finally {
		    sess.close();
		}
		/*
		// with disconnect
		System.out.println("disconnect/connect and accessing");
		sess = sf.openSession();
		tx = null;
		WithLazySet l5 = null;
		try {
			tx = sess.beginTransaction();

			l5 = (WithLazySet) sess.get(WithLazySet.class, l.getId());
	
			
			
			tx.commit();
		} catch (HibernateException e) {
		    if (tx!=null) tx.rollback();
		    throw e;
		}
		finally {
		    sess.disconnect();
		}
		
		sess.reconnect();
		
		for (Iterator iter = l5.getLazy().iterator(); iter.hasNext();) {
			InLazySet lazy = (InLazySet) iter.next();
			System.out.println("loaded: " + lazy.getId());
		}
		sess.close();
		*/
		try {
		Thread.sleep(5000);
		} catch(InterruptedException ie) {
			ie.printStackTrace();
		}
		System.out.println("Next round");
		}
	}	
}