目標

servlet、jsp實現簡單聊天室，用戶通過瀏覽器登錄后進入聊天室，可發送消息進行群聊，點擊聊天信息框中的用戶名可實現拍一拍功能。

基礎知識

ServletContext上下文對象：一直存在于服務器，存儲公有、 共享數據Session會話對象：獨立

實現思路

1.登錄頁面 login.jsp 輸入昵稱

2.編寫一個LoginSevlet，處理登錄提交的昵稱，保存登錄昵稱到session（會話變量）若昵稱合法 if(nickname.length()!=0)，跳轉到聊天室，不合法回到登錄頁面

3.編寫聊天室頁面chatroom.jsp ，是一個框架，把多個頁面集成到一個頁面中

<iframe src='http://www.b3g6.com/bcjs/message.jsp' height='70%'> </iframe><iframe src='http://www.b3g6.com/bcjs/input.jsp' height='25%'> </iframe>

4.聊天內容顯示message.jsp，不斷自動刷新標簽內設置響應頭,用${上下文變量}顯示聊天內容

<meta http-equiv='refresh' content='1'>

5.input.jsp（不刷新）輸入聊天內容文本框text，點擊發送聊天內容按鈕時，將把文本框的聊天信息提交給ChatServlet處理。下方有超鏈接可退出聊天室。

<a href='http://www.b3g6.com/bcjs/login.jsp' target='_top'>退出聊天室</a>

6.ChatServlet：檢測聊天信息合法性，把聊天信息加入到ServletContext變量（字符串）中，（每次都將xx:xxxx加入上下文字符串）判斷是否存在該變量，存在則直接讀取現有聊天內容，把數據加入進去后，重新寫回上下文變量

7.實現拍一拍功能（目的：學習如何進行鏈接操作）每個人名做成一個鏈接，訪問某一個servlet，該servlet可以在聊天信息（上下文變量）里添加一行，xx拍了yyy一下，跳轉回message.jsp問題：鏈接里應該包含yyy參數，servlet？nick=yyy

say = '<a href=’NickServlet?nickname='+nickname+'’target=’_parent’>'+nickname+'</a>'+':'+text;

8.多人聊天實現：多種類型瀏覽器

關鍵代碼

login.jsp

昵稱：<input type='text' name='nickname'/><br> <br><br><input type='submit' value='登錄'/><input type='reset' value='取消'/>

input.jsp

<form action='input.do' method='post'> <input type='text' size='50' name='text'/> <input type='submit' value='發送'><br><br><br><br> <a href='http://www.b3g6.com/bcjs/login.jsp' rel='external nofollow' rel='external nofollow' target='_top'>退出聊天室</a></form>

message.jsp

<h3>一起來聊天吧</h3>${says}

LoginServlet.java

package chatting;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;import java.io.PrintWriter;@WebServlet(name = 'LoginServlet2',urlPatterns = {'/login.do'})public class LoginServlet2 extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //避免亂碼 response.setContentType('text/html;charset=utf-8'); request.setCharacterEncoding('utf-8'); //nickname保存用戶昵稱 String nickname = request.getParameter('nickname'); //nickname存儲到session變量中 HttpSession session = request.getSession(); session.setAttribute('nickname',nickname); //對nickname進行合法性判斷 if(nickname.length()!=0){ //昵稱合法，則進入聊天室頁面 request.getRequestDispatcher('/chatroom.jsp').forward(request,response); } else{ //昵稱不合法，返回登陸頁面 request.getRequestDispatcher('/login.jsp').forward(request,response); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { }}

ChatServlet.java

package chatting;import javax.servlet.RequestDispatcher;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;import java.util.Vector;@WebServlet(name = 'ChatServlet',urlPatterns = '/input.do')public class ChatServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //防止亂碼 request.setCharacterEncoding('utf-8'); response.setContentType('text/html;charset=utf-8'); HttpSession session = request.getSession(); String text = request.getParameter('text'); //text存儲聊天信息，并進行合法性判斷 if (text.length()!=0) { String say =new String(); //獲取session中的昵稱 String nickname = (String)session.getAttribute('nickname'); //將昵稱作為鏈接，并傳參 say = '<a href=’NickServlet?nickname='+nickname+'’target=’_parent’>'+nickname+'</a>'+':'+text; String says = new String(); //將昵稱和聊天信息一起放在上下文變量 ServletContext context = getServletContext(); if(context.getAttribute('says')!=null){ says = context.getAttribute('says') + say + '<br>'; } else{ says = say + '<br>'; } context.setAttribute('says', says); request.setAttribute('says', says); } //轉發 RequestDispatcher dispatcher = request.getRequestDispatcher('/input.jsp'); dispatcher.forward(request, response); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { }}

NickServlet.java

package chatting;import javax.servlet.RequestDispatcher;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;import java.io.PrintWriter;@WebServlet(name = 'NickServlet',urlPatterns = '/NickServlet')public class NickServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType('text/html;charset=UTF-8'); request.setCharacterEncoding('utf-8'); //將拍一拍放到上下文變量says中 一起輸出 HttpSession session = request.getSession(); //nickname存儲當前用戶昵稱 String nickname = (String)session.getAttribute('nickname'); //name存儲連接中傳遞的參數，即被拍的用戶昵稱 String name = java.net.URLDecoder.decode(request.getParameter('nickname'),'UTF-8'); String pick = nickname+'拍了拍'+name+'<br>'; ServletContext context = request.getServletContext(); String says = context.getAttribute('says')+pick; context.setAttribute('says',says); RequestDispatcher dispatcher = request.getRequestDispatcher('/chatroom.jsp'); dispatcher.forward(request, response); }}

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持好吧啦網。