MVC_自定义框架

实现MVC自定义框架（简单实现登录功能）
一，模型层：
实体类，接口（实体类接口，Action接口），接口实现类（实体类接口实现类，Action接口实现类）
代码：

package entity;
/**
 * 用户类
 * @author Administrator
 */
public class User {
	private String username;//用户名
	private String password;//密码
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	
}
package dao;

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

/**
 * Action接口
 * @author Administrator
 *
 */
public interface Action {
	public String execute(HttpServletRequest request,HttpServletResponse response);
}
package dao;

import entity.User;

/**
 * 用户类接口
 * @author Administrator
 */
public interface UserDao {
	//登录方法
	public User login(String username,String password);
}
package dao.impl;

import dao.UserDao;
import entity.User;
/**
 * 用户接口的实现类
 * @author Administrator
 */
public class UserDaoImpl implements UserDao {
	/**
	 * 登录
	 */
	public User login(String username, String password) {
		User user=null;
		if(username.equals("admin")&&password.equals("admin")){
			user=new User();
			user.setPassword(password);
			user.setUsername(username);
		}
		return user;
	}

}
package dao.impl;

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

import dao.Action;
import entity.User;
/**
 * 登录Action类实现Action接口
 * @author Administrator
 */
public class LoginAction implements Action {

	public String execute(HttpServletRequest request,
			HttpServletResponse response) {
			//接收参数
		String username=request.getParameter("username");
		String password=request.getParameter("password");
		//创建UserDaoImpl对象
		UserDaoImpl udi=new UserDaoImpl();
		//调用登录方法
		User user=udi.login(username, password);
		//判断 User对象是否为空
		if(user!=null){
			return "success.jsp";
		}else{
			return "error.jsp";
			
		}
	}

}

二、控制器层，ActionServlet类（添加一个获得Action的方法）
web.xml:配置如下

   <servlet-name>ActionServlet</servlet-name>
    <servlet-class>servlet.ActionServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>ActionServlet</servlet-name>
    <url-pattern>*.action</url-pattern><!-- 过滤所有以.action结尾 -->
  </servlet-mapping>

package servlet;

import java.io.IOException;

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

import dao.Action;
import dao.impl.LoginAction;

public class ActionServlet extends HttpServlet {

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doPost(request,response);
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//得到Action对象
		Action action=getAction(request);
		//调用Action实现类方法
		try {
			String result=action.execute(request, response);
			if(result!=null){
				response.sendRedirect(result);
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		
	}
	/**
	 * 创建一个获得Action的方法
	 * @param request
	 */
	public  static Action getAction(HttpServletRequest request){
		Action action=null;
		//截取action请求名(例如页面的登录：<form action="login.action" method="post">)
		String uri=request.getRequestURI();
		System.out.println("request.getRequestURI()---"+uri);
		//结果：request.getRequestURI()---/qifei_mvc_kuangjia_zuoye/login.action
		StringBuffer url=request.getRequestURL();
		System.out.println("request.getRequestURL()--"+url);
		//结果：request.getRequestURL()--http://localhost:8080/qifei_mvc_kuangjia_zuoye/login.action
		String contextPath=request.getContextPath();
		//结果：request.getContextPath()--/qifei_mvc_kuangjia_zuoye
		System.out.println("request.getContextPath()--"+contextPath);
		String actionUrl=uri.substring(contextPath.length());
		System.out.println("actionUrl--"+actionUrl);
		String actionName=actionUrl.substring(1,actionUrl.lastIndexOf(".")).trim();
		
		//判断请求名
	if(actionName.equals("login")){
			action=new LoginAction();
		}
		return action;
	}

}

三、页面

<body>
   <form action="login.action" method="post">
   	用户名：<input type="text" name="username"/><br/>
   	密码：<input type="password" name="password"/><br/>
   	<input type="submit" value="提交">
   </form>
  </body>