一个小程序得逻辑问题，如何解决？在线等待，立刻给分

pingju 2002-04-26 09:41:23

想做一个通过applet聊天的web小程序，服务器端就一个servlet负责收集applet中的文本框内容然后显示出来。想将内容放置到servletcontext对象中让大家都能看见，类似与asp中application 变量做的聊天室。可我做的东西，只能自己发的自己看见，别人看不见，看看我的程序，怎么改？

servlet文件：
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class GetServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/html; charset=GBK";
/**Initialize global variables*/
public void init() throws ServletException {
}
/**Process the HTTP Get request*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType(CONTENT_TYPE);
PrintStream out=new PrintStream(response.getOutputStream());
ServletContext sc=getServletContext();
String s=request.getParameter("name");
String s1="";

if(sc.getAttribute("talk")==null)
{
s1="";
}
else
{
s1=s1+request.getParameter("name");
}
sc.setAttribute("talk",s1);
String s2=(String)sc.getAttribute("talk");
out.println(s2);
out.close();
}
/**Clean up resources*/
public void destroy() {
}
}
***我知道问题出现在变量s1上，他只保存着每个人的信息，而不是全局的。应怎么样改？？

applet文件：

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.net.*;
import java.io.*;
public class GetApplet extends Applet
{

Panel panel1=new Panel();
Label label1=new Label();
TextField nameFd=new TextField();
BorderLayout borderlayout1=new BorderLayout();
Button sendBtn=new Button();
TextArea result=new TextArea();

/**Construct the applet*/
public GetApplet() {
}
/**Initialize the applet*/
public void init() {
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
/**Component initialization*/
private void jbInit() throws Exception
{
this.setSize(300,160);
label1.setText("姓名");
this.setLayout(borderlayout1);
nameFd.setColumns(20);
sendBtn.setLabel("发送");
sendBtn.addActionListener(new B1());

this.add(panel1,BorderLayout.NORTH);
panel1.add(label1,null);
panel1.add(nameFd,null);
panel1.add(sendBtn,null);
this.add(result,BorderLayout.CENTER);

}

void sendBtn_actionPerformed(ActionEvent e)
{
String protocol=getCodeBase().getProtocol();
int port=getCodeBase().getPort();
String host=getCodeBase().getHost();
try
{

URL url= new URL(protocol + "://" + host + ":" + port + "/test/servlet/GetServlet?name=" + URLEncoder.encode(nameFd.getText()));

DataInputStream reader=new DataInputStream(url.openStream());
result.append("echo:姓名=" + reader.readLine() + "\r\n");
}
catch(MalformedURLException mle)
{
}
catch(IOException ioe)
{
}

}
class B1 implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
//getAppletContext().showStatus("Button 1");

String protocol=getCodeBase().getProtocol();
int port=getCodeBase().getPort();
String host=getCodeBase().getHost();
try
{

URL url= new URL(protocol + "://" + host + ":" + port + "/test/servlet/GetServlet?name=" + URLEncoder.encode(nameFd.getText()));

DataInputStream reader=new DataInputStream(url.openStream());
result.append("echo:姓名=" + reader.readLine() + "\r\n");
}
catch(MalformedURLException mle)
{
}
catch(IOException ioe)
{
}

}
}

/**Get Applet information*/
public String getAppletInfo() {
return "Applet Information";
}
/**Get parameter info*/
public String[][] getParameterInfo() {
return null;
}
}

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