package com.yanek.test;

import java.io.IOException;
import java.lang.reflect.Method;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class TestServlet extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
 // 获取类的全路径以及名称
 String className = request.getParameter("className");
 // 获取方法名
 String methodName = request.getParameter("method");
 try {
  // 获取class文件
  Class<?> t_class = Class.forName(className);
  // 获取该类所需求的方法
  Method method = t_class.getDeclaredMethod(methodName,
   HttpServletRequest.class, HttpServletResponse.class);
  method.invoke(t_class.newInstance(), request, response);// 方法的实现
 } catch (Exception e) {
  e.printStackTrace();
 }
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
 doGet(request, response);
 }

}

package com.yanek.test;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Test {

 /**
 * @param args
 */
 public static void main(String[] args) {

 System.out.println("hello world !");

 }

 public void test(HttpServletRequest request, HttpServletResponse response) {
 System.out.println("hello");
 System.out.println(request.getParameter("username"));
 }

}

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 <servlet>
 <description>Test</description>
 <display-name>Test</display-name>
 <servlet-name>Test</servlet-name>
 <servlet-class>com.yanek.test.TestServlet</servlet-class>
 <load-on-startup>1</load-on-startup>
 </servlet>
 <servlet-mapping>
 <servlet-name>Test</servlet-name>
 <url-pattern>/Test</url-pattern>
 </servlet-mapping>
 <welcome-file-list>
 <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>
 <login-config>
 <auth-method>BASIC</auth-method>
 </login-config>
</web-app>