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java web如何实现简单聊天室 java web实现简单聊天室代码

时间:2020-11-23 17:05:15 编辑:袖梨 来源:一聚教程网

java web如何实现简单聊天室?本篇文章小编给大家分享一下java web实现简单聊天室代码,文章代码介绍的很详细,小编觉得挺不错的,现在分享给大家供大家参考,有需要的小伙伴们可以来看看。

目标

servlet、jsp实现简单聊天室,用户通过浏览器登录后进入聊天室,可发送消息进行群聊,点击聊天信息框中的用户名可实现拍一拍功能。

基础知识

数据的存取 setAttribute / getAttribute

request请求对象 :有效时间短

ServletContext上下文对象:一直存在于服务器,存储公有、 共享数据

Session会话对象:独立

网站默认页面一般是index.jsp

实现思路

1.登录页面 login.jsp 输入昵称

2.编写一个LoginSevlet,处理登录提交的昵称,保存登录昵称到session(会话变量)

若昵称合法 if(nickname.length()!=0),跳转到聊天室,不合法回到登录页面

3.编写聊天室页面chatroom.jsp ,是一个框架,把多个页面集成到一个页面中


4.聊天内容显示message.jsp,不断自动刷新标签内设置响应头,用${上下文变量}显示聊天内容

5.input.jsp(不刷新)输入聊天内容文本框text,点击发送聊天内容按钮时,将把文本框的聊天信息提交给ChatServlet处理。下方有超链接可退出聊天室。

退出聊天室

6.ChatServlet:检测聊天信息合法性,把聊天信息加入到ServletContext变量(字符串)中,(每次都将xx:xxxx加入上下文字符串)

判断是否存在该变量,存在则直接读取现有聊天内容,把数据加入进去后,重新写回上下文变量

7.实现拍一拍功能(目的:学习如何进行链接操作)

每个人名做成一个链接,访问某一个servlet,该servlet可以在聊天信息(上下文变量)里添加一行,xx拍了yyy一下,跳转回message.jsp

问题:链接里应该包含yyy参数,servlet?nick=yyy

say = ""+nickname+""+":"+text;

8.多人聊天实现:多种类型浏览器

关键代码

login.jsp

昵称:


input.jsp





退出聊天室

message.jsp

一起来聊天吧

${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 {
 //避免乱码
 response.setContentType("text/html;charset=utf-8");
 request.setCharacterEncoding("utf-8");
 //nickname保存用户昵称
 String nickname = request.getParameter("nickname");
 //nickname存储到session变量中
 HttpSession session = request.getSession();
 session.setAttribute("nickname",nickname);
 //对nickname进行合法性判断
 if(nickname.length()!=0){
 //昵称合法,则进入聊天室页面
  request.getRequestDispatcher("/chatroom.jsp").forward(request,response);
 }
 else{
 //昵称不合法,返回登陆页面
  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 {
 //防止乱码
 request.setCharacterEncoding("utf-8");
 response.setContentType("text/html;charset=utf-8");
 HttpSession session = request.getSession();
 String text = request.getParameter("text");
 //text存储聊天信息,并进行合法性判断
 if (text.length()!=0) {
  String say =new String();
  //获取session中的昵称
  String nickname = (String)session.getAttribute("nickname");
  //将昵称作为链接,并传参
  say = ""+nickname+""+":"+text;
  String says = new String();
  //将昵称和聊天信息一起放在上下文变量
  ServletContext context = getServletContext();
  if(context.getAttribute("says")!=null){
  says = context.getAttribute("says") + say + "
"; } else{ says = say + "
"; } context.setAttribute("says", says); request.setAttribute("says", says); } //转发 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");
 //将拍一拍放到上下文变量says中 一起输出

 HttpSession session = request.getSession();
 //nickname存储当前用户昵称
 String nickname = (String)session.getAttribute("nickname");
 //name存储连接中传递的参数,即被拍的用户昵称
 String name = java.net.URLDecoder.decode(request.getParameter("nickname"),"UTF-8");
 String pick = nickname+"拍了拍"+name+"
"; ServletContext context = request.getServletContext(); String says = context.getAttribute("says")+pick; context.setAttribute("says",says); RequestDispatcher dispatcher = request.getRequestDispatcher("/chatroom.jsp"); dispatcher.forward(request, response); } }

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