模仿struts改进版:中央控制器

package com.bjpowernode.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

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

import com.ankangqiao.servlet.UserManager;

@SuppressWarnings("serial")
public class TestServlet extends HttpServlet {

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

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

		response.setContentType("text/html; charset=UTF-8");
		PrintWriter out = response.getWriter();

		String requestUIR = request.getRequestURI();
		System.out.println("requestUIR:" + requestUIR);

		String path = requestUIR.substring(requestUIR.indexOf("/", 1),
				requestUIR.indexOf("."));
		System.out.println("path:" + path);

		String forward = "";

		String username = request.getParameter("username");
		Action action = null;

		if (username != null) {
			username = new String(username.getBytes("ISO-8859-1"), "UTF-8");
			if (path.equals("/Servlet/addUser")) {
				action = new AddUserAction();
			} else if (path.equals("/Servlet/deleteUser")) {
				action = new DeleteUserAction();
			} else if (path.equals("/Servlet/modifyUser")) {
				action = new ModifyUserAction();
			} else if (path.equals("/Servlet/queryUser")) {
				action = new QueryUserAction();
			} else {
				out.print("访问失败!");
			}

			try {
				forward = action.execute(request, response);
				request.getRequestDispatcher(forward)
						.forward(request, response);
			} catch (Exception e) {
				e.printStackTrace();
				out.print("增删改查失败!");
			}

		}

	}

}
/**
 * <action-config>
 * 	  <action path="/servlet/delUser" type="com.bjpowernode.servlet.DelUserAction">
 * 		<forward name="success">/del_success.jsp</forward>
 * 		<forward name="error">/del_error.jsp</forward>		
 *    </action 	
 *    
 * 	  <action path="/servlet/addUser" type="com.bjpowernode.servlet.AddUserAction">
 * 		<forward name="success">/add_success.jsp</forward>
 * 		<forward name="error">/add_error.jsp</forward>		
 *    </action
 *     	
 * 	  <action path="/servlet/modifyUser" type="com.bjpowernode.servlet.ModifyUserAction">
 * 		<forward name="success">/modify_success.jsp</forward>
 * 		<forward name="error">/modify_error.jsp</forward>		
 *    </action 	
 * 
 * 	  <action path="/servlet/queryUser" type="com.bjpowernode.servlet.QueryUserAction">
 * 		<forward name="success">/query_success.jsp</forward>
 * 		<forward name="error">/query_error.jsp</forward>		
 *    </action 	
 * 
 * 	  
 * </action-config>
 * 
 * ActionMapping {
 * 	  private String path;
 *    private String type;
 *    Map forwardMap; 
 * 
 * }
 * forwardMap {
 * 	  key="success";
 *    value="/del_success.jsp"
 *    key="error"
 *    value="/del_error.jsp"
 * }
 * 
 * 
 * Map map = new HashMap();
 * map.put("/servlet/delUser", actionMapping);
 * map.put("/servlet/addUser", actionMapping);
 * map.put("/servlet/modifyUser", actionMapping);
 * map.put("/servlet/queryUser", actionMapping);
 * 
 * 如果是删除ActionMapping存储如下：
 * actionMapping {
 * 	path= "/servlet/delUser";
 *  type = "com.bjpowernode.servlet.DelUserAction";
 *  forwardMap {
 *  	key="success",value="/del_success.jsp"
 *      key="error", value="/del_error.jsp"
 *  }
 * }
 * 
 *  
 * String path = "/servlet/delUser";
 * 
 * 根据截取的URL请求，到Map中取得本次请求对应的Action
 * ActionMappint actionMappint = (ActionMappint)map.get(path);
 * 
 * 取得本请求对应的Action类的完整路径
 * String type = actionMappint.getType(); //com.bjpowernode.servlet.DelUserAction
 * 
 * 采用反射动态实例化Action
 * Action action = (Action)class.forName(type).newInstance();
 * 
 * 动态待用Action中的execute方法 
 * String forward = action.execute(request, response);
 * 
 * 根据路径完成转向
 * request.getRequestDispatcher(forward).forward(request, response);
 */

<?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">
  <display-name></display-name>	
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
  	<servlet-name>TestServlet</servlet-name>
  	<servlet-class>com.bjpowernode.servlet.TestServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>TestServlet</servlet-name>
  	<url-pattern>*.action</url-pattern>
  </servlet-mapping>
</web-app>