servlet串行拦截器实现例子

至于串行过滤器有什么作用，我实在不知。我的理解是它只是说明过滤器的串行运行方式

需求：当用户没有登录访问更新页面的时候，跳转到登录页面

1.登录页面：login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<form action="UserLoginServlet" method="post">

    username:<input type="text" value="<%=null == request.getAttribute("username")?"" : request.getAttribute("username") %>" name="username"><br>

    password:<input type="text" name="password"><br>

    authority:<select  name="authority">

        <option value="1" <%="1".equals(request.getAttribute("authority"))?"selected = selected" : "" %>>common user</option>

        <option value="2" <%="2".equals(request.getAttribute("authority"))?"selected = selected" : "" %>>adminstrator</option>

    </select>

    <br>

    <input type="submit">

</form>

</body>

</html>

2.登录页面的servet容器

package com.filter;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import com.javabean.User;

public class UserLoginServlet extends HttpServlet

{

    @Override

    protected void doPost(HttpServletRequest req, HttpServletResponse resp)

            throws ServletException, IOException

    {

        String username = (String)req.getParameter("username");

        String password = (String)req.getParameter("password");

        String authority = (String)req.getParameter("authority");

        if("1".equals(authority) && "zhangsan".equals(username) && "123".equals(password))

        {

            User user = new User();

            user.setUsername(username);

            user.setPassword(password);

            user.setAuthority(authority);

            HttpSession session = req.getSession();

            session.setAttribute("user",user);

            req.getRequestDispatcher("index.jsp").forward(req, resp);

            return ;

        }

        if("2".equals(authority) && "lisi".equals(username) && "456".equals(password))

        {

            User user = new User();

            user.setUsername(username);

            user.setPassword(password);

            user.setAuthority(authority);

            HttpSession session = req.getSession();

            session.setAttribute("user",user);

            req.getRequestDispatcher("index.jsp").forward(req, resp);

            return ;

        }

        System.out.println("meiyou denglu");

        resp.sendRedirect("login.jsp?error=true&username="+username+"&authority="+authority);

    }

}

UserLoginServlet

3.主页面index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

    <%@ page import="com.javabean.User" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<a href="QueryServletFilter">query</a><br>

<%

User user = (User)session.getAttribute("user");

if(null == user)

{

    response.sendRedirect("login.jsp");

    return;

}

    if("2".equals(((User)session.getAttribute("user")).getAuthority())){

%>

<a href="UpdateServletFilter">update</a>

<%} %>

</body>

</html>

index.jsp

4.查询servlet. QueryServletFilter

package com.filter;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class QueryServletFilter extends HttpServlet

{

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp)

            throws ServletException, IOException

    {

        System.out.println("QueryServletFilter run");

    }

}

5.更新servlet容器. UpdateServletFilter

package com.filter;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class UpdateServletFilter extends HttpServlet

{

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp)

            throws ServletException, IOException

    {

        System.out.println("UpdateServletFilter run");

    }

}

UpdateServletFilter

6.web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">

  <display-name>filter</display-name>

 <servlet>

     <servlet-name>UserLoginServlet</servlet-name>

     <servlet-class>com.filter.UserLoginServlet</servlet-class>

 </servlet>

  <servlet-mapping>

     <servlet-name>UserLoginServlet</servlet-name>

     <url-pattern>/filter/UserLoginServlet</url-pattern>

 </servlet-mapping>

 <servlet>

     <servlet-name>QueryServletFilter</servlet-name>

     <servlet-class>com.filter.QueryServletFilter</servlet-class>

 </servlet>

 <servlet-mapping>

     <servlet-name>QueryServletFilter</servlet-name>

     <url-pattern>/filter/QueryServletFilter</url-pattern>

 </servlet-mapping>

 <servlet>

     <servlet-name>UpdateServletFilter</servlet-name>

     <servlet-class>com.filter.UpdateServletFilter</servlet-class>

 </servlet>

 <servlet-mapping>

     <servlet-name>UpdateServletFilter</servlet-name>

     <url-pattern>/filter/UpdateServletFilter</url-pattern>

 </servlet-mapping>

  <!-- filter start -->

  <filter>

      <description>this is the servlet filter example</description>

      <filter-name>userLoginServletFilter1</filter-name>

      <filter-class>com.filter.UserLoginServletFilter</filter-class>

  </filter>

    <!-- 演示过滤器串行运行 -->

  <filter>

      <description>this is the servlet filter example</description>

      <filter-name>userLoginServletFilter2</filter-name>

      <filter-class>com.filter.UserLoginServletFilter2</filter-class>

  </filter>

  <!-- url-pattern表示只过滤 UpdateServletFilter这一个servlet容器-->

  <filter-mapping>

      <filter-name>userLoginServletFilter1</filter-name>

      <url-pattern>/filter/UpdateServletFilter</url-pattern>

  </filter-mapping>

  <!-- url-pattern表示只过滤 UpdateServletFilter这一个servlet容器-->

  <filter-mapping>

      <filter-name>userLoginServletFilter2</filter-name>

      <url-pattern>/filter/UpdateServletFilter</url-pattern>

  </filter-mapping>

  <!-- filter end -->

</web-app>

web.xml

7.filter拦截器 UserLoginServletFilter

package com.filter;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

public class UserLoginServletFilter implements Filter

{

    @Override

    public void destroy()

    {

      System.out.println("destroy");

    }

    @Override

    public void doFilter(ServletRequest request, ServletResponse response,

            FilterChain filterChain) throws IOException, ServletException

    {

        HttpServletRequest req = (HttpServletRequest)request;

        HttpSession s = req.getSession();

        if(req.getRequestURI().endsWith("login.jsp") || req.getRequestURI().endsWith("UserLoginServlet"))

        {

            System.out.println("Filter1 start");

            filterChain.doFilter(request, response);

            System.out.println("filter1 end");

            return ;

        }

        if(null ==  s.getAttribute("user"))

        {

            System.out.println("Filter1 start..");

            ((HttpServletResponse)response).sendRedirect("login.jsp");

            return;

        }

        else

        {

            System.out.println("Filter1 start....");

            filterChain.doFilter(request, response);

        }

    }

    @Override

    public void init(FilterConfig filterConfig) throws ServletException

    {

       System.out.println("init");

    }

}

UserLoginServletFilter

8.filter拦截器2 UserLoginServletFilter2

package com.filter;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

public class UserLoginServletFilter2 implements Filter

{

    @Override

    public void destroy()

    {

       System.out.println("destory2");

    }

    @Override

    public void doFilter(ServletRequest request, ServletResponse response,

            FilterChain filterChain) throws IOException, ServletException

    {

       System.out.println("doFilter2 start");

       filterChain.doFilter(request, response);

       System.out.println("doFilter2 end");

    }

    @Override

    public void init(FilterConfig arg0) throws ServletException

    {

        System.out.println("init2");

    }

}

UserLoginServletFilter2

web.xml中url-pattern属性值表示访问的路径。

servlet串行拦截器实现例子的更多相关文章

过滤器(servlet.filter)和拦截器(springmvc.interceptor)区别
①拦截器是基于java的反射机制的,而过滤器是基于函数回调. ②拦截器不依赖与servlet容器,过滤器依赖与servlet容器. ③拦截器只能对action请求起作用,而过滤器则可以对几乎所有的请求 ...
Servlet 过滤器、拦截器、监听器以及文件上传下载
在学习之初,总是对过滤器.拦截器.监听器这三个搞不清楚,现在进行一些记录,方便大家交流,也为了提高自身的学习能力! 如果想要了解这三个的作用,首先对servlet流程进行熟悉了解,servlet是客户 ...
struts2动态调用+Servlet过滤器+struts2拦截器
周末真的是懒到心慌...... 本文是在完整s2sh项目基础上添加的,不太了解s2sh项目构建的朋友可以先参考一下这几篇文章: eclipse环境下基于tomcat-7.0.82构建struts2项目 ...
AngularJS 拦截器和应用例子(转)
$httpAngularJS 的 $http 服务允许我们通过发送 HTTP 请求方式与后台进行通信.在某些情况下,我们希望可以俘获所有的请求,并且在将其发送到服务端之前进行操作.还有一些情况是,我们 ...
AngularJS 拦截器和好棒例子
目录[-] 什么是拦截器? 异步操作例子 Session 注入(请求拦截器) 时间戳(请求和响应拦截器) 请求恢复 (请求异常拦截) Session 恢复 (响应异常拦截器) 总结 Intercep ...
Spring MVC - 拦截器实现和用户登陆例子
1.拦截器 SpringMvc中的拦截器实现了HandlerInterceptor接口,通常使用与身份认证,授权和校验,模板视图,统一处理等: public class HanderIntercept ...
java 拦截器、过滤器、监听器
一.理解Struts2拦截器 1. Struts2拦截器是在访问某个Action或Action的某个方法,字段之前或之后实施拦截,并且Struts2拦截器是可插拔的,拦截器是AOP的一种实现． 2. ...
Struts2拦截器和标签
一.struts2拦截器 1.struts2是框架,封装了很多的功能,struts2里面封装的功能都是在拦截器里面. 2 struts2里面封装了很多的功能,有很多拦截器,不是每次这些拦截器都执行,每 ...
1.5(Spring MVC学习笔记) 拦截器（Interceptor）
一.拦截器 1.1拦截器简介 Spring中的拦截器类似Servlet中的过滤器(Filter),主要用于拦截用户请求, 并进行一定的处理操作(如验证权限.记录日志.设置编码方式等). 1.2拦截器实 ...

随机推荐

Java中判断String对象是否为空的方法
Java原生的方法: String对象中有一个isEmpty的方法判断是否为空,其实isEmpty完全等同于string.length()==0,注意如果String本身是null,那么使用strin ...
跟开涛学SpringMVC（4.1）：Controller接口控制器详解（1）
http://www.importnew.com/19397.html http://blog.csdn.net/u014607184/article/details/52074530 https:/ ...
js转换金额为中文大写
function changeMoneyToChinese(money){ var cnNums = new Array("零","壹","贰&quo ...
牛人写的facebook优化php来龙去脉
背景 HHVM 是 Facebook 开发的高性能 PHP 虚拟机,宣称比官方的快9倍,我很好奇,于是抽空简单了解了一下,并整理出这篇文章,希望能回答清楚两方面的问题: HHVM 到底靠谱么?是否可以 ...
hdu1034 简单模拟
这里开一个二维数组.num[105][2]; 我也不知道N有多少,随便开的, 那么这里num[i][0] 表示当前第 i 个人拥有的糖果数,num[i][1]表示他上面一个人分给他的糖果数.详 ...
android 5.2
watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvc2VyZ2V5Y2Fv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA ...
ssm 网页
http://stackoverflow.com/questions/14545872/bean-named-xxx-must-be-of-typexxx-but-was-actually-of-ty ...
Android的logger机制分析
分析安卓的Logger机制一.概述 Logger机制是在Android系统中提供的一个轻量级的日志系统,这个日志系统是以驱动程序的形式在内核空间实现的,在用户空间分别提供了Java接口和C/C++接 ...
python datetime获取几分钟、小时、天之前的时间
import datetime print ((datetime.datetime.now()-datetime.timedelta(days=1)).strftime("%Y-%m-%d ...
Unsupported major.minor version (jdk版本错误)解决方案办法
如果你遇到了 Unsupported major.minor version ,请认真看一下,说不定会有帮助. 我花两个小时总结的经验,你可能10分钟就得到了. ^**^ 一.错误现象: 当改变了jd ...

servlet串行拦截器实现例子

servlet串行拦截器实现例子的更多相关文章

随机推荐

热门专题