这次的applet部分做了很大的修改：
package applet;import javax.swing.JApplet;import javax.swing.JTextPane;import javax.swing.JScrollPane;import javax.swing.text.html.HTMLDocument;import javax.swing.text.html.HTMLEditorKit;import javax.swing.event.HyperlinkListener;import javax.swing.event.HyperlinkEvent;import java.awt.event.MouseListener;import java.awt.event.MouseEvent;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.IOException;import java.net.Socket;import java.net.URL;
/** *//**
* This class is used to define response of communication * * @author Zenny Chen *
*/class CommunicationProtocol ...{ static final String OK_RESPONSE = "OK"; static final String NG_RESPONSE = "NG";}/** *//** * This applet is used for a text area that can make some particular * strings displayed as hyperlinks. So some components in Java Swing * are used.<br> * NB:Java swing is really powerful! * * @author Zenny Chen * */public class TestApplet extends JApplet implements HyperlinkListener, Runnable, MouseListener ...{ 
/** *//** * Without this, there will be a warning.
*/ private static final long serialVersionUID = -5281871014922105280L; private static final String PARAM_NAME = "func"; /** *//** * client socket */ private Socket sock = null; /** *//** * the applet running thread */ private Thread thread = null; /** *//** * Please see j2se docs */ private HTMLEditorKit edit = null; /** *//** * Please see j2se docs */ private HTMLDocument doc = null; /** *//** * Please see j2se docs */ private JTextPane textpane = null; /** *//** * Please see j2se docs */ private JScrollPane scroll = null; /** *//** * the URL which is specified by the user when a hyperlink is * clicked. */ private volatile String socketURL = null; /** *//** * Flag that marks whether connecting to the server has failed. */ private volatile boolean isFailed = false; /** *//** * the port number of the server(hard coded here) */ private final int port = 8079; /** *//** * the url of the server<br> * This will be passed to the applet through JavaScript. */ private String urlname = ""; /** *//** * store the parameter that is defined in HTML <object> tag */ private String param = ""; /** *//** * Initialize the applet. */ public void init() ...{ param = this.getParameter(PARAM_NAME); edit = new HTMLEditorKit(); doc = new HTMLDocument(); textpane = new JTextPane(doc); textpane.setEditorKit(edit); scroll = new JScrollPane(textpane, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS); getContentPane().add(scroll); textpane.setEditable(false); textpane.addHyperlinkListener(this); scroll.addMouseListener(this); System.out.println("applet initialized"); } /** *//** * Start the applet and make it running. */ public void start() ...{ System.out.println("applet start"); if(thread == null) ...{ thread = new Thread(this); thread.start(); } } /** *//** * Stop the applet. */ public void stop() ...{ try ...{ if(sock != null) ...{ sock.close(); sock = null; } } catch(IOException e) ...{ System.out.println("socket stop exception"); } if(thread != null && thread.isAlive()) ...{ Thread.yield(); thread = null; } System.out.println("applet stop"); } /** *//** * the applet's running method * */ public void