当我使用applet代替框架时，对话框没有显示系统的项目？

Question

我的代码是：

import java.io.*;
import java.awt.event.*;
import java.awt.*;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
import java.util.*;
import java.io.*;
import java.util.zip.GZIPOutputStream;
import java.util.*;
import java.awt.Checkbox;
import javax.swing.SwingUtilities;
import javax.swing.JButton;
import java.awt.CheckboxGroup;
import java.applet.*;
import javax.swing.JFileChooser;

/*
<applet code="compress1" width=200 height=200>
</applet>
*/



interface CompressionStrategy
{
public void compressFiles(FileOutputStream  files,String str);
}



                class ZipCompressionStrategy implements CompressionStrategy{
    public void compressFiles(FileOutputStream  files, String str)
    {
        byte[] buffer = new byte[1024];
        try{
        //using ZIP approach
        ZipOutputStream zos = new ZipOutputStream(files);
            ZipEntry ze= new ZipEntry(str);
            zos.putNextEntry(ze);
            FileInputStream in = new FileInputStream(str);
            int len;
            while ((len = in.read(buffer)) > 0) {
                zos.write(buffer, 0, len);
            }

            in.close();
            zos.closeEntry();

            //remember close it
            zos.close();

            System.out.println("Done with Zip");
        }
    catch(IOException ex){
           ex.printStackTrace();}
}
}


     class GZipCompressionStrategy implements CompressionStrategy
    {
    public void compressFiles(FileOutputStream  files, String str)
    {
                 //using RAR approach
                //FileOutputStream fos = null;
                  GZIPOutputStream gos = null;
                  FileInputStream fis = null;

         try {
           // fos = new FileOutputStream("e://myGzip.gzip");
            gos = new GZIPOutputStream(files);
            fis = new FileInputStream(str);
            byte[] tmp = new byte[4*1024];
            int size = 0;
            while ((size = fis.read(tmp)) != -1) {
                gos.write(tmp, 0, size); }

            gos.finish();
            System.out.println("Done with GZip...");
          } 

    catch (IOException e) {}

    finally{
            try{
                if(fis != null) fis.close();
                if(gos != null) gos.close();
            } catch(Exception ex){}
          }


    }

}


 class CompressionContext

{

private CompressionStrategy strategy;  

//this can be set at runtime by the application preferences

public void setCompressionStrategy(CompressionStrategy strategy)

{

this.strategy = strategy; 

}
//use the strategy

public void createArchive(FileOutputStream  files, String str)
{
strategy.compressFiles(files,str);
}
}

public class compress1 extends Applet implements ActionListener
{

int n;

Button b1;

Checkbox jcb1,jcb2;

CheckboxGroup cbg;

int r;

JFileChooser fs=new JFileChooser();

File file1;

static String filenm;
//TextField tf;
public void init()

{

//setTitle("compress");

Panel p1;

//setLayout(new FlowLayout());

p1=new Panel();

b1=new Button("compress");

cbg=new CheckboxGroup();

jcb1=new Checkbox("zip1",cbg,true);

jcb2=new Checkbox("gzip1",cbg,false);

//b1.setPreferredSize(new Dimension(100,100));

b1.addActionListener(this);

//tf=new TextField("",6);

p1.add(b1);

//p1.add(tf);

p1.add(jcb1);

p1.add(jcb2);

add(p1,BorderLayout.NORTH);

}

public void actionPerformed(ActionEvent event)
{

if(event.getSource()==b1)
{
 r=fs.showOpenDialog(null);
if(r==JFileChooser.APPROVE_OPTION)
{
file1=fs.getSelectedFile();

filenm=file1.getAbsolutePath();

}


if(jcb1.getLabel()=="zip1"){
n=1;

}
else if(jcb2.getLabel()=="gzip1"){
n=2;
}
else{}
compress1.x(n);


}

} 

static void x(int  n)
{

CompressionContext ctx = new CompressionContext();

switch(n)

{

//ctx.setCompressionStrategy(new ZipCompressionStrategy());  

case 1:

ctx.setCompressionStrategy(new ZipCompressionStrategy());    

  //get a list of files



 try{

 FileOutputStream fos = new FileOutputStream("f:\\MyFile1.zip");

//String st="f:\\MyFile1.zip";

ctx.createArchive(fos,filenm);   

 }

catch(IOException ex){

           ex.printStackTrace();}

break;

case 2:

ctx.setCompressionStrategy(new GZipCompressionStrategy());    

  //get a list of files

 try{

 FileOutputStream fos = new FileOutputStream("f:\\MyFile1.gzip");

//String st="f:\\MyFile.zip";

ctx.createArchive(fos,filenm);   

 }
catch(IOException ex){

           ex.printStackTrace();}

 break;

case 3:

System.exit(0);

}

}


}

这是压缩文件的代码。当我使用框架时，它正常工作，但当现在我正在使用applet然后对话框没有显示任何路径元素时代替框架，我不知道发生了什么。