struts的简单实现

 Java Code 

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package cn.netjava.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 cn.netjava.action.Action;
import cn.netjava.action.ActionFactory;

public class ControlServlet extends HttpServlet{
    private static final long serialVersionUID = 1L;

    protected void service(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
        //得到当前servlet的请求路径
        String pathName = request.getServletPath();
        //request.getContextPath();
        //得到项目名字
        System.out.println("pathName:"+pathName);
        //得到请求的Action名字
        int index=pathName.indexOf('.');
        String ActionName=pathName.substring(1,index);
        System.out.println("ActionName:"+ActionName);
        //获取运行时参数
        String actionClassName=this.getInitParameter(ActionName);
        //得到Action对象
        Action action=ActionFactory.getActionFactory().getAction(actionClassName);
        //执行Action的execute得到要返回的URL路径
        String url = action.execute(request,response);
        if(url==null){
            request.getRequestDispatcher("error.jsp").forward(request, response);
        }else {
            request.getRequestDispatcher(url).forward(request, response);
        }
    }
}

 Java Code 

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package cn.netjava.action;

public interface Action {
    /**
     * 所有Action类继承这个接口
     * @param request 请求对象
     * @param response 响应对象
     * @return 返回页面地址
     */
    public String execute(javax.servlet.http.HttpServletRequest request,javax.servlet.http.HttpServletResponse response);
}

 Java Code 

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package cn.netjava.action;

public class ActionFactory {
    //单例模式不需要创建对象
    private static ActionFactory af;
    private ActionFactory(){}
    public static ActionFactory getActionFactory() {
        if(af == null)
        {
            af=new ActionFactory();
        }
        return af;
    }
    public Action getAction(String ActionClassName)
    {
        Action action =null;
        try {
            //利用反射根据类名创建对象
            action =(Action)Class.forName(ActionClassName).newInstance();
        }catch(Exception e)
        {
            e.printStackTrace();
        }
        return action;
    }
}

 Java Code 

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 XML Code 

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<servlet>
    <servlet-name>controlServlet</servlet-name>
    <servlet-class>cn.netjava.servlet.ControlServlet</servlet-class>
    <init-param>
        <param-name>loginAction</param-name>
        <param-value>cn.netjava.action.LoginAction</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    
    <servlet-name>controlServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>

 HTML Code 

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <title></title>
</head>

<body>
  <form action="loginAction.do" method="post">
    <table border="1" cellspacing="0" cellpadding="10" width="70%" style="border:red soild;border-collapse:collapse">
      <tr>
        

        <td colspan="2" align="center">用户名： <input type="text" name="username" id="username" value="" /><br /></td>
      </tr>

      <tr>
        <td></td>
      </tr>

      <tr>
        <td colspan="2" align="center">密码： <input type="password" name="password" id="password" value="" /><br /></td>
      </tr>

      <tr>
        <th><input type="submit" value="登陆" /> <input type="checkbox" name="savePW" value="true" />记住密码 <input type="button" value="注册" onclick="location.href='register.jsp'" /></th>
      </tr>
    </table>
  </form>
</body>
</html>