1．介绍：本文的主要目的就是通过Java语言开发基于html通信的聊天程序，主要用到了ajax，html通信，java,jsp。穿越防火墙，在web页面进行通信，没有利用socket，不用另外开设端口进行通信。仅仅利用浏览器的80端口就可以搞定。下面列出主要的代码结构:下面给出涉及到的各个代码：1．ChatService.java类：packagelee;importjava.util.*;importjava.io.*;/**@version1.0*/publicclassChatService{privatestaticChatServicecs;privatePropertiesuserList;privateLinkedList<String>chatMsg;privateChatService(){}publicstaticChatServiceinstance(){if(cs==null){cs=newChatService();}returncs;}publicbooleanvalidLogin(Stringuser,Stringpass)throwsIOException{if(loadUser().getProperty(user)==null){returnfalse;}if(loadUser().getProperty(user).equals(pass)){returntrue;}returnfalse;}publicbooleanaddUser(Stringname,Stringpass)throwsException{if(userList==null){userList=loadUser();}if(userList.containsKey(name)){thrownewException("用户名已经存在，请重新选择用户名");}userList.setProperty(name,pass);saveUserList();returntrue;}publicStringgetMsg(){if(chatMsg==null){chatMsg=newLinkedList<String>();return"";}Stringresult="";for(Stringtmp:chatMsg){result+=tmp+"\n";}returnresu《}publicvoidaddMsg(Stringuser,Stringmsg){if(chatMsg==null){chatMsg=newLinkedList<String>();}if(chatMsg.size()>40){chatMsg.removeFirst();}chatMsg.add(user+"说："+msg);}////////////////////////////////////////////////////////////////下面是系统的工具方法/////////////////////////////////////////////////////////////privatePropertiesloadUser()throwsIOException{if(userList==null){Filef=newFile("userFile.properties");if(!f.exists())f.createNewFile();userList=newProperties();userList.load(newFileInputStream(f));}returnuserList;}privatebooleansaveUserList()throwsIOException{if(userList==null){returnfalse;}userList.store(newFileOutputStream("userFile.properties"),"userList");returntrue;}}2.ChatServlet.javapackagelee;importjavax.servlet.ServletException;importjavax.servlet.ServletContext;importjavax.servlet.RequestDispatcher;importjavax.servlet..Servlet;importjavax.servlet..ServletRequest;importjavax.servlet..ServletResponse;importjava.io.PrintWriter;importjava.io.IOException;/**@version1.0*Date:*/publicclassChatServletextendsServlet{publicvoidservice(ServletRequestrequest,ServletResponseresponse)throwsIOException,ServletException{request.setCharacterEncoding("UTF-8");Stringmsg=request.getParameter("chatMsg");if(msg!=null!msg.equals("")){Stringuser=(String)request.getSession(true).getAttribute("user");ChatService.instance().addMsg(user,msg);}//设置中文流response.setContentType("text/html;charset=GBK");PrintWriterout=response.getWriter();out.println(ChatService.instance().getMsg());}}3.LoginServlet.javapackagelee;importjavax.servlet.ServletException;importjavax.servlet.ServletContext;importjavax.servlet.RequestDispatcher;importjavax.servlet..Servlet;importjavax.servlet..ServletRequest;importjavax.servlet..ServletResponse;importjava.io.PrintWriter;importjava.io.IOException;/**@author*Date:*/publicclassLoginServletextendsServlet{publicvoidservice(ServletRequestrequest,ServletResponseresponse)throwsIOException,ServletException{Stringname=request.getParameter("name");Stringpass=request.getParameter("pass");if(name==null||pass==null){request.setAttribute("error","用户名和密码都不能为空");forward("/index.jsp",request,response);}if(ChatService.instance().validLogin(name,pass)){re...