chatroomservlet.java

用jsp做的聊天室系统。包括index、liao1、in、liao、Del等页面

package onlyfun.caterpillar;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.LinkedList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ChatRoomServlet extends javax.servlet.http.HttpServlet implements
    javax.servlet.Servlet {
      private static LinkedList<Message> messages = new LinkedList<Message>(); 

      private List<Message> addMessage(String text) {
        if (text != null && text.trim().length() > 0) {  
          messages.addFirst(new Message(text)); 
          while (messages.size() > 10) { 
               messages.removeLast();  
          }  
        }  
        return messages;  
     } 

     private List<Message> getMessages() {
        return messages; 
     }  

      protected void doPost(HttpServletRequest request, HttpServletResponse response)  
         throws ServletException, IOException { 
           List<Message> list = null; 
              if("send".equals(request.getParameter("task"))) { 
               String msg = request.getParameter("msg");  
               // 中文处理
               msg = new String(msg.getBytes("ISO-8859-1"), "UTF8"); 
               list = addMessage(msg); 
              } else if("query".equals(request.getParameter("task"))){ 
               list = getMessages();
              }   

              response.setContentType("text/xml");
              response.setHeader("Cache-Control", "no-cache"); 
              response.setCharacterEncoding("UTF8");  
              PrintWriter out = response.getWriter(); 
              out.println("<messages>");  
              for(int i = 0; i < list.size(); i++) { 
                String msg = list.get(i).getText(); 
                out.println("<message>" + msg + "</message>");  
              } 
       
              out.println("</messages>"); 
            out.close();  
        }  
   }