JSP实现简易的聊天功能（Session机制）

基于服务器端全局应用空间 application 的简易聊天室实现

1.login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>聊天室登录</title>
</head>
<style>
.div1{background-color:skyblue;border:solid 1px black;width:300px;height:170px;text-align:center;line-height:150%
}
</style>
<body>
<div class="div1">
<%
StringBuffer view=new StringBuffer("");
session.setAttribute("view",view);
String color="balck";
session.setAttribute("Color",color);
%>
<h3>聊天室登录</h3>
<form action="cotainer.jsp" method="post">
用户名：<input type="text" name="userName"><br>
<br>
<input type="submit" value="登录"></form>
</div>
</body>
</html>

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2.container.jsp

<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML>
<html><head><style>
.div3{background-color:lightgreen;border:solid 1px black;width:700px;height:600px;line-height:150%
}
img{width:15px;height:20px;
}
</style></head><body><div class="div3"><%request.setCharacterEncoding("utf-8");if(request.getParameter("userName")!=null){session.setAttribute("userName",request.getParameter("userName").toString());}String sessionID=session.getId();StringBuffer users=new StringBuffer();//确定用户数量if(application.getAttribute("count")!=null){users=users.append(application.getAttribute("users").toString());if(users.indexOf(sessionID)==-1){session.setAttribute("isNew","true");int  userCount= Integer.parseInt(application.getAttribute("count").toString());userCount++;application.setAttribute("count",new Integer(userCount));users=users.append("<br>"+sessionID);application.setAttribute("users",users.toString());}}else{users=users.append("<br>"+sessionID);application.setAttribute("users", users.toString());application.setAttribute("count", "1");}//获取默认颜色String select="black";if(request.getParameter("Color")!=null)select=request.getParameter("Color").toString();request.setAttribute("select",select);//确定用户次序int userId=1;String[]userss=users.toString().split("<br>");for(int i=0;i<userss.length;i++){if(userss[i].equals(sessionID)){userId=i;break;}}%>您是第<img src="数字/<%=userId%>.png">位访问者!<jsp:include page="view.jsp" /><form action="cotainer.jsp" method="post"><input type="text" name="message"><input type="hidden" name="send" value="true">选择我的颜色：<select name="color"><option value="red" ${select=="red"?'selected':''}>红色</option><option value="blue" ${select=="blue"?'selected':''}>蓝色</option><option value="green" ${select=="green"?'selected':''}>绿色</option><option value="black" ${select=="black"?'selected':''}>黑色</option><option value="yellow" ${select=="yellow"?'selected':''}>黄色</option><option value="purpole" ${select=="purpole"?'selected':''}>紫色</option></select><input type="submit" value="发送"> </form><form action="cotainer.jsp"><input type="hidden" name="clear" value="true"><input type="submit" value="清空"></form><form action="cotainer.jsp"><input type="hidden" name="flush" value="true"><input type="submit" value="刷新"></form><form action="login.jsp"><input type="submit" value="退出聊天"></form></div> </body>
</html>

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view.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8" import="java.util.*" import="java.text.SimpleDateFormat"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>聊天</title>
<style>
.div2{border:solid 1px black;width:500px;height:400px;overflow-y:scroll; 
}</style>
</head>
<body><%request.setCharacterEncoding("utf-8");String userName = session.getAttribute("userName").toString();if(request.getParameter("color")!=null)session.setAttribute("Color",request.getParameter("color").toString());String color=session.getAttribute("Color").toString();request.setAttribute("select",color);StringBuffer view=new StringBuffer();view.append(session.getAttribute("view").toString());String chatTexts="";//判断是不是新用户String isNew="false";if(session.getAttribute("isNew")!=null){isNew=session.getAttribute("isNew").toString();session.setAttribute("isNew","false");}if(isNew.equals("false")){ //发送String send="false";if (request.getParameter("send") != null)send = "true";if(send.equals("true")){if (request.getParameter("message") != null) {String message = request.getParameter("message").toString();Date time = new Date();SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");String time1 = sdf.format(time);String chatText ="<br>"+ userName + "["+time1 + "]:" + message;view.append(chatText);session.setAttribute("view",view.toString());//view存到application中if (application.getAttribute("chatText") != null) {String ss=application.getAttribute("chatText").toString();					StringBuffer ssb=new StringBuffer();ssb.append(ss);ssb.append(chatText);application.setAttribute("chatText",ssb.toString());}else{application.setAttribute("chatText",view.toString());}}}//清空String clear="false";if (request.getParameter("clear") != null)clear = "true";if(clear.equals("true")){view.delete(0,view.length());}session.setAttribute("view",view.toString());//刷新String flush="false";if (request.getParameter("flush") != null)flush ="true";if (flush.equals("true")) {if (application.getAttribute("chatText") != null) {chatTexts=application.getAttribute("chatText").toString();view.delete(0,view.length());view.append(chatTexts);session.setAttribute("view",view.toString());}}//加颜色String scolor=view.toString();String[]a=scolor.split("<br>");for(int i=0;i<a.length;i++){						if(a[i].contains((userName+"["))){if(a[i].contains("<span")){//问题一：字符串取子串a[i]=a[i].substring(0,a[i].length()-7);int index=a[i].lastIndexOf(">");a[i]=a[i].substring(index+1);}a[i]="<br><span style='color:"+color+"'>"+a[i]+"</span>";}else{a[i]="<br>"+a[i];}}StringBuffer sb=new StringBuffer();for(String s:a){sb.append(s);}view.delete(0,view.length());view.append(sb.toString());}%>
<div class="div2">
<%=view.toString() %>
</div>
</body>
</html>

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通过切换不同的浏览器可以实现在本机进行聊天。
（2）聊天室网站建好后，若尝试和同学一块开展聊天，你分享给他人的网站地址的构成应该是什么？
网址的构成：http://localhost:8080/项目名/…
（3）如果该网站只在本机能够使用，而其他同学无法访问，请分析原因是什么？应如何解决这个问题？
运行的项目不再同一局域网内。
解决办法：
一般我们想在别人电脑上运行本机tomcat项目，不考虑服务器的话，必须在同一局域网中，而网线连接和无线网络连接之间还是有很多不同的，流程基本都是在本机将项目运行起来，然后找到本机ip，将http://localhost:8080/项目名/…中的localhost换成本机ip（注意：必须在同一局域网中）。