使用URLClassLoader调用外部jar，并执行指定类方法

/**
	 * 加载jar，并得到指定的类
	 * 
	 * @param jarFileName
	 * @param classFullName
	 * @return
	 * @throws MalformedURLException
	 */
	private Class loadClass(String jarFileName, String classFullName)
			throws MalformedURLException {
		//要使用URLClassLoader，因为不是同工程下，同工程下可使用ClassLoader
		URLClassLoader classLoader = new URLClassLoader(new URL[] { new URL(
				jarFileName) });
		JarFile jarFile = null;
		Class c = null;
		try {
			jarFile = new JarFile(jarFileName.substring(5));
		} catch (IOException e) {
			e.printStackTrace();
		}
		Enumeration<JarEntry> en = jarFile.entries();
		while (en.hasMoreElements()) {
			JarEntry je = en.nextElement();
			String name = je.getName();
			String s5 = name.replace('/', '.');
			if (s5.lastIndexOf(".class") > 0) {
				String className = je
						.getName()
						.substring(0, je.getName().length() - ".class".length())
						.replace('/', '.');
				if (classFullName.equals(className)) {
					try {
						c = classLoader.loadClass(className);
						System.out.println(className);
					} catch (ClassNotFoundException e) {
						System.out.println("NO CLASS: " + className);
					} catch (NoClassDefFoundError e) {
						System.out.println("NO CLASS: " + className);
					}
					break;
				}

			}
		}
		return c;
	}

protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		Class clazz = this.loadClass("file:C:" + File.separator + "Main.jar",
				"com.test.Main");
		System.out.println("开始执行！");
		// com.test.Main类中的二个方法，为了测试返回值写死，可以得到类中的方法集合
		String[] me_name = new String[] { "main", "a" };
		for (int i = 0; i < me_name.length; i++) {
			try {
				Method me = clazz.getMethod(me_name[i],
						new Class[] { new String[] {}.getClass() });
				// 方法的返回值,可以给方法加参数
				Object object = me.invoke(clazz.newInstance(), new Object[] { new String[] { "111111111" } });
				System.out.println(object);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		System.out.println("开始js！");
	}