Struts01---入门小案例

创建web项目实现的效果！用户点击页面不同的链接，后台调用不同的代码！

创建两个类实现共同的接口！

public interface Action { 

    String  execute();

}

public class LoginAction  implements Action{

    public  String  execute(){

        System.out.println("LoginAction......");

        return  "success";

    }

}

public class ListAction implements Action {

    public  String  execute(){

        System.out.println("ListAction......");

        return  "success";

    }

}

想让用户能访问到我们的后台代码，要么使用servlet 要么使用filter!

使用filter

创建一个filter用来拦截用户的请求

public class DoFilter implements Filter {

    //全局的变量

     Map<String,String> map=new  HashMap<String, String>();

     //初始化操作

    @Override

    public void init(FilterConfig arg0) throws ServletException {

        System.out.println("DoFilter 初始化了.............................");

     //  key是用户请求的路径  value 是对应的全类名

        map.put("/login","cn.bdqn.action.LoginAction");

        map.put("/list","cn.bdqn.action.ListAction");

    }

    //真正的处理

    @Override

    public void doFilter(ServletRequest request, ServletResponse response,

            FilterChain chain) throws IOException, ServletException {

         //向下转型

        HttpServletRequest httpServletRequest=(HttpServletRequest) request;

        HttpServletResponse httpServletResponse=(HttpServletResponse) response;

        //看一下 各个路径的区别

        System.out.println("getContextPath()==>"+httpServletRequest.getContextPath());//项目名

        System.out.println("getServletPath()==>"+httpServletRequest.getServletPath());//访问的路径

        System.out.println("getRequestURI()==>"+httpServletRequest.getRequestURI());//项目下面的路径

        System.out.println("getRequestURL()==>"+httpServletRequest.getRequestURL());//带协议的完整路径

       //应该使用getServletPath

        String  path=httpServletRequest.getServletPath();

        try {

            if (path.equals("/index.jsp")) {

                chain.doFilter(request, response);  //放行

            }else{

                Action action=(Action) Class.forName(map.get(path)).newInstance();

                action.execute();

                //跳转到成功界面

                httpServletRequest.getRequestDispatcher("/success.jsp").forward(request, response);

            }

        } catch (InstantiationException e) {

            e.printStackTrace();

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        } catch (ClassNotFoundException e) {

            e.printStackTrace();

        }

    }

    @Override

    public void destroy() {

    }

}

前台页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>

    <meta http-equiv="pragma" content="no-cache">

    <meta http-equiv="cache-control" content="no-cache">

    <meta http-equiv="expires" content="0">

    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

    <meta http-equiv="description" content="This is my page">

    <!--

    <link rel="stylesheet" type="text/css" href="styles.css">

    -->

  </head>

  <body>

    <a  href="login">登录 </a>

    <a  href="list">详情 </a>

  </body>

</html>

sucess.jsp页面就是一个成功界面！！！省略掉！

我们使用xml文件来代替 map中所保存的键值对信息！

key：用户的请求

value:对应的后台实现类全类名！

巴特西

Struts01---入门小案例

最新文章

热门文章