java web實現(xiàn)簡單聊天室

更新時間：2020年11月23日 11:42:21 作者：今天肝代碼了嗎

這篇文章主要為大家詳細介紹了java-web實現(xiàn)簡單聊天室，含拍一拍功能，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

目標

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

基礎(chǔ)知識

數(shù)據(jù)的存取 setAttribute / getAttribute
request請求對象：有效時間短

ServletContext上下文對象：一直存在于服務(wù)器，存儲公有、共享數(shù)據(jù)
Session會話對象：獨立

網(wǎng)站默認頁面一般是index.jsp

實現(xiàn)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(zhuǎn)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="message.jsp" width="100%" height="70%"> </iframe>
<iframe src="input.jsp" width="100%" height="25%"> </iframe>

4.聊天內(nèi)容顯示message.jsp，不斷自動刷新標簽內(nèi)設(shè)置響應(yīng)頭,用${上下文變量}顯示聊天內(nèi)容

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

5.input.jsp（不刷新）輸入聊天內(nèi)容文本框text，點擊發(fā)送聊天內(nèi)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="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(xiàn)有聊天內(nèi)容，把數(shù)據(jù)加入進去后，重新寫回上下文變量

7.實現(xiàn)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(zhuǎn)回message.jsp
問題：鏈接里應(yīng)該包含yyy參數(shù)，servlet？nick=yyy

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

8.多人聊天實現(xiàn)：多種類型瀏覽器

關(guān)鍵代碼

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(fā)送"><br><br><br><br>
 <a href="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(zhuǎn)發(fā)
 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(shù)，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(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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