classloaderproptest.java

疯狂Java讲义_源码(含Java设计模式CHM

import java.net.*;
import java.util.*;
import java.io.*;

/**
 * Description:
 * <br/>Copyright (C), 2008-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public class ClassLoaderPropTest
{
	public static void main(String[] args)
		throws IOException
	{
		//获取系统类加载器
		ClassLoader systemLoader = 
			ClassLoader.getSystemClassLoader();
		System.out.println("系统类加载器：" + systemLoader);
		/*
		获取系统类加载器的加载路径——通常由CLASSPATH环境变量指定
		如果操作系统没有指定CLASSPATH环境变量，默认以当前路径作为
		系统类加载器的加载路径
		*/
		Enumeration<URL> em1 = systemLoader.getResources("");
		while(em1.hasMoreElements())
		{
			System.out.println(em1.nextElement());
		}
 		//获取系统类加载器的父类加载器——应该得到扩展类加载器
		ClassLoader extensionLader = systemLoader.getParent();
		System.out.println("扩展类加载器：" + extensionLader);
		System.out.println("扩展类加载器的加载路径：" + System.getProperty("java.ext.dirs"));
		System.out.println("扩展类加载器的parent: " 
			+ extensionLader.getParent());
	}
}