一，Filter
FilterEncoding 过滤器，统一设置servlet的编码格式。
package com.dkt.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 FilterEncoding implements Filter{
private String encoding;
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
request.setCharacterEncoding(encoding);
response.setCharacterEncoding(encoding);
chain.doFilter(request, response);
}
public void init(FilterConfig filterConfig) throws ServletException {
// encoding 在web.xml中配置。开启服务器即加载
encoding = filterConfig.getInitParameter("encoding");
System.out.println(encoding);
}
}
FilterLogin 过滤器,访问页面时，过滤没有登录的用户，跳转到登录页面
package com.dkt.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.HttpSession;
public class FilterLogin implements Filter{
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest hrequest = (HttpServletRequest)request;
HttpSession session = hrequest.getSession();
Object name = session.getAttribute("name");
if (("").equals(name)||name==null) {
session.setAttribute("error", "*您还没有登录，请先登录");
/*
* 从goodsinfo文件夹下的goodsone页面中，跳转到loginFilter.jsp页面时，需向外跳一级
* request.getRequestDispatcher("../loginFilter.jsp").forward(request, response);
* 从WEB-INF文件下的userinfo文件夹下的userone.jsp页面跳到loginFilter.jsp页面。
* 需要向外跳两级。且WEB-INF文件夹的文件不能再外部通过http直接访问，
* 只能通过内部request的方式跳转页面
*/
//request.getRequestDispatcher("loginFilter.jsp").forward(request, response);
request.getRequestDispatcher("loginFilter.jsp").forward(request, response);
}else {
chain.doFilter(request, response);
}
}
public void destroy() {
}
public void init(FilterConfig arg0) throws ServletException {
}
}
二，Listener
ListenerOnline 监听器，监听在线人数。并存在application作用域中
package com.dkt.listener;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
public class ListenerOnline implements HttpSessionAttributeListener,
HttpSessionListener{
private static int count;//统计在线人数
public void attributeAdded(HttpSessionBindingEvent se) {
HttpSession session = se.getSession();
Object username = session.getAttribute("name");
if (username!=null&&!("").equals(username)) {
count++;
session.getServletContext().setAttribute("count", count);
}
}
public void attributeRemoved(HttpSessionBindingEvent se) {
}
public void attributeReplaced(HttpSessionBindingEvent se) {
}
public void sessionCreated(HttpSessionEvent se) {
}
public void sessionDestroyed(HttpSessionEvent se) {
if (count>0) {
count--;
se.getSession().getServletContext().setAttribute("count", count);
}
}
}
ListenerR 简单实用监听器
package com.dkt.listener;
import javax.servlet.ServletRequestAttributeEvent;
import javax.servlet.ServletRequestAttributeListener;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
public class ListenerR implements ServletRequestAttributeListener,
ServletRequestListener{
public void attributeAdded(ServletRequestAttributeEvent srae) {
System.out.println("属性添加");
}
public void attributeRemoved(ServletRequestAttributeEvent srae) {
System.out.println("属性移除");
}
public void attributeReplaced(ServletRequestAttributeEvent srae) {
System.out.println("属性替换");
}
public void requestDestroyed(ServletRequestEvent sre) {
System.out.println("销毁");
}
public void requestInitialized(ServletRequestEvent sre) {
System.out.println("初始化");
}
}
三，servlet
TestEncodingTwo 验证FilterEncoding 和 ListenerR
package com.dkt.servlet;
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 TestEncodingTwo 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");
String name = request.getParameter("name");
String hobby = request.getParameter("hobby");
System.out.println(name+"----"+hobby);
request.setAttribute("name", name);
request.setAttribute("hobby", hobby);
/*
初始化
属性替换
销毁
初始化
属性替换
星星----男
属性添加
属性添加
销毁
*/
}
}
LoginServlet
package com.dkt.servlet;
import java.io.IOException;
import java.io.PrintWriter;
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.dkt.dao.UserJdbc;
public class LoginServlet 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");
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
HttpSession session = request.getSession();
String op = request.getParameter("op");
System.out.println("op----------->"+op);
if (("login").equals(op)) {
String name = request.getParameter("name");
String password = request.getParameter("password");
Boolean bool = new UserJdbc().validate(name, password);
if (bool) {
session.setAttribute("name", name);
request.getRequestDispatcher("/WEB-INF/userinfo/userone.jsp").forward(request, response);
}else {
request.getRequestDispatcher("../../loginFilter.jsp").forward(request, response);
}
}else if (("a").equals(op)) {
request.setAttribute("aaa", "apple");
PrintWriter out = response.getWriter();
out.print("apple");//responseText;
out.flush();
out.close();
}else if(("exit").equals(op)){
Object name = session.getAttribute("name");
session.invalidate();//销毁session
request.getRequestDispatcher("/WEB-INF/userinfo/userone.jsp").forward(request, response);
}
}
}
四，jsp
loginFilter.jsp
<%@ 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 'MyJsp.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>
<form action="LoginServlet?op=login" method="post">
<span style="font-size: 12px;color: red;">${error }</span><br/>
用户名：<input type="text" name = "name" value=""><br/><br/>
密 码：<input type="password" name = "password" ><br/>
<input type="submit" value="登录">
<input type="reset" value="重置"><br/>
</form>
<form action="LoginServlet?op=exit" method="post">
<input type="submit" value="退出" />
</form>
</body>
</html>
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@page import="com.dkt.entity.UserInfo"%>
<%@ taglib uri="hello" prefix="hello" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
用户信息：${name }<br/>
当前在线人数：${count }
<hr/>
</body>
</html>
五，web.xml
<?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">
<!-- 配置登录过滤器 -->
<filter>
<filter-name>loginfilter</filter-name>
<filter-class>com.dkt.filter.FilterLogin</filter-class>
</filter>
<!-- 过滤器适用于多个页面时，可重复多个filter-mappingm,以提供多个页面进行过滤 -->
<filter-mapping>
<filter-name>loginfilter</filter-name>
<url-pattern>/try.jsp</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>loginfilter</filter-name>
<url-pattern>/goodsinfo/*</url-pattern><!-- 过滤goodsinfo文件夹下的所有文件 -->
</filter-mapping>
<filter-mapping>
<filter-name>loginfilter</filter-name>
<url-pattern>/WEB-INF/userinfo/*</url-pattern><!-- 过滤WEB-INF文件夹下的userinfo文件夹下的所有文件 -->
</filter-mapping>
<filter-mapping>
<filter-name>loginfilter</filter-name>
<url-pattern>/FilterServlet</url-pattern><!-- 过滤servlet -->
</filter-mapping>
<!-- 当访问temp.jsp页面时会先执行过滤器，如果用户已登录则可访问
如果没用登录，session里面没有存name属性，则跳到登录页面，让用户登录.
登录成功在跳到temp.jsp
-->
<!-- 初始化过滤器，统一设置编码格式 -->
<filter>
<filter-name>filterEncoding</filter-name>
<filter-class>com.dkt.filter.FilterEncoding</filter-class>
<!-- 过滤初始化，设置servlet的编码格式 -->
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>filterEncoding</filter-name>
<url-pattern>/servlet/*</url-pattern>
<!-- 过滤servlet下的所有servlet，初始化设置编码格式 此servlet下不是包名，是下面的mapping中的url-pattern路径 -->
</filter-mapping>
<!-- request监听 -->
<listener>
<listener-class>com.dkt.listener.ListenerR</listener-class>
</listener>
<listener>
<listener-class>com.dkt.listener.ListenerOnline</listener-class>
</listener>
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.dkt.servlet.LoginServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>TestEncodingTwo</servlet-name>
<servlet-class>com.dkt.servlet.TestEncodingTwo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>TestEncodingTwo</servlet-name>
<url-pattern>/servlet/TestEncodingTwo</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>