基于Servlet跟Properties的JSP聊天室案例 _JavaScript

基于Servlet和Properties的JSP聊天室案例

package com.demo.service;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.LinkedList;
import java.util.Properties;

public class ChatService {

	// 使用单例模式来设计CharService
	private static ChatService cs;
	// 使用Properties对象保存系统的所有用户
	private Properties userList;
	// 使用LinkedList对象保存聊天信息
	private LinkedList<String> chatMsg;
	// 构造器私有
	private ChatService() {
	}
	// 通过静态方法返回唯一的ChatService对象
	public static ChatService instance() {
		if (cs == null) {
			cs = new ChatService();
		}
		return cs;
	}
	// 验证用户登陆
	public boolean validLogin(String user, String pass) 
	throws IOException {
		String loadPass = loadUser().getProperty(user);
		if (loadPass != null && loadPass.equals(pass)) {
			return true;
		}
		return false;
	}

	//用户注册
	public boolean addUser(String name,String pass)
	throws Exception{
		//当userList为null，初始化userList对象
		if(userList==null){
			userList=loadUser();
		}
		//如果用户名存在
		if(userList.containsKey(name)){
				throw new Exception("用户名已存在！");
		}
		userList.setProperty(name, pass);
		saveUserList();
		return true;
	}
	
	//获取系统中所用的聊天信息
	public String getMsg(){
		//如果ChatMsg对象为null，表面不曾开始聊天
		if(chatMsg==null){
			chatMsg=new LinkedList<String>();
			return "";
		}
		StringBuilder resultStr=new StringBuilder("");
		//将chatMsg中所有聊天信息拼接起来
		for(String tmp:chatMsg){
			resultStr.append(tmp+"\n");
		}
		return resultStr.toString();
	}
	//用户发言，添加聊天信息
	public void addMsg(String user,String msg){
		//如果chatMsg对象为null，初始化chatMsg对象
		if(chatMsg==null){
			chatMsg=new LinkedList<String>();
		}
		//chatMsg超过40条时，将前面的聊天信息删除
		if(chatMsg.size()>40){
			chatMsg.removeFirst();
		}
		chatMsg.add(user+"说:"+msg);
	}
	/* 下面是系统的工具方法 */
	// 读取系统用户信息
	private Properties loadUser() throws IOException {

		if (userList == null) {
			File f = new File("userFile.properties");
			if (!f.exists()) {
				f.createNewFile();
			}
			userList = new Properties();
			userList.load(new FileInputStream(f));
		}
		return userList;
	}

	// 保存系统所用用户
	private boolean saveUserList() throws IOException {
		if (userList == null) {
			return false;
		}
		// 将userList信息保存到Properties文件中
		userList.store(new FileOutputStream
				("userFile.properties"),
				"Users Info List");
		return true;
	}
}

package com.demo.service;


import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ChatServlet extends HttpServlet {
	@Override
	protected void service(HttpServletRequest request, 
			HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		request.setCharacterEncoding("GBK");
		String msg=request.getParameter("chatMsg");
		if(msg!=null&!msg.equals("")){
			String user=(String)request.getSession(true)
			.getAttribute("user");
			ChatService.instance().addMsg(user, msg);
		}
		request.setAttribute("msg", 
				ChatService.instance().getMsg());
		forward("/chat.jsp",request,response);
//		super.service(request, response);
	}
	private void forward(String url, HttpServletRequest request,
			HttpServletResponse response) 
	throws ServletException, IOException {
		// TODO Auto-generated method stub
		RequestDispatcher rd=request.getRequestDispatcher(url);
		rd.forward(request, response);
	}
}

<%@ page contentType="text/html;charset=GBK" errorPage="error.jsp"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
	"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=GBK" />
		<title>聊天页面</title>
	</head>
	<body>
		<table width="780" border="1" align="center">
			<tr>
				<td>
					<p align="center">
						<textarea name="textarea" cols="100" rows="30" 
						readonly="readonly">${requestScope.msg}</textarea>
					</p>
					<form name="form1" method="post" action="chat.do">
						<div align="center">
							<input name="chatMsg" type="text" size="90"
								onclick="document.form1.submit";/>
							<input type="submit" name="Submit" value="发送" />
						</div>
					</form>
				</td>
			</tr>
		</table>
<script>
var input = document.getElementById("chatMsg");
input.focus();
function check() {
	if (input.value == null || input.value == "") {
		alert("请输入聊天信息，不要发送空信息!");
		return false;
	}
}
function submitChat() {
	document.getElementById("form1").onsubmit();
}
document.getElementById("form1").onsubmit = check;
</script>
	</body>
</html>