从从指定地方加载类(定制ClassLoader)

 Java代码  

package com.masf;

import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;

public class MyClassloader {

    /**
     * @param args
     * @throws MalformedURLException
     */
    @SuppressWarnings("unchecked")
    public static void main(String[] args) throws MalformedURLException {
        //自定义类加载路径
        String path = "file:/D:/classes/";
        //String jarpath = "jar:/D:/lib/";

        URL[] urls = {new URL(path)};
        //这里没有指定父类加载器，所以不会有向上委托;这个类加载器，只会在自己指定的路径内寻找类
        ClassLoader loader = new URLClassLoader(urls,null);
        try {
            //在自定义的类加载路径中查找类
            Class classzz = loader.loadClass("com.masf.Person");
            System.out.println("加载路径："+loader.getResource(""));
            System.out.println("类加载器："+classzz.getClassLoader());
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

}

////////////////////////////////////////////////////////////////////
package com.masf;

public class Person {

}