文件的复制

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
public class FrmMain extends Applet implements Runnable, ActionListener
{
    private TextArea msg;
    private JTextField t;
    private JButton b1;
    private JButton b2;
    private JPanel p;
   
    private FileInputStream fin=null;
    private FileOutputStream fout=null;
   
    private String pathname=null;
    private String filename=null;
    private byte buf[];
   
    Thread th;
        
    public void init()
    {
        msg=new TextArea(50,20);
        t=new JTextField(20);
        b1=new JButton(\"选择\");
        b2=new JButton(\"复制\");
        b1.setFont(new Font(\"DialogInput\", 0, 12));
        b2.setFont(new Font(\"DialogInput\", 0, 12));
        p=new JPanel();
        this.setLayout(new BorderLayout());
        this.add(\"Center\",msg);
        this.add(\"South\",p);
        p.add(t);
        p.add(b1);
        p.add(b2);

        b1.addActionListener(this);
        b2.addActionListener(this);
    }
    public void run()
    {
        try
        {
            fin=new FileInputStream(pathname);
            fout=new FileOutputStream(filename);
            buf=new byte[1024];
            msg.append(\"正在复制文件\"+filename+\"\n\");
            while(fin.read(buf)!=-1)
            {
                fout.write(buf);   
            }
            msg.append(\"复制成功!\n\");
        }
        catch(Exception e)
        {
            System.out.println(e);
            msg.append(\"复制失败！\n\");
        }
        
    }
    public static void main(String[] args)
    {
        FrmMain app=new FrmMain();
        Frame frm=new Frame(\"坏碟文件拷贝工具\");
        app.init();
        app.start();
        frm.add(app);
        frm.setSize(400,300);
        frm.setResizable(false);
        Dimension d=Toolkit.getDefaultToolkit().getScreenSize();
        Dimension f=frm.getSize();
        frm.setLocation(d.width/2-f.width/2,d.height/2-f.height/2);
        frm.show();
        frm.addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent evt)
            {
                System.exit(0);
            }
        });
    }

    public void actionPerformed(ActionEvent e)
    {
        if(e.getActionCommand().equals(\"选择\"))
        {
            FileDialog fdlg=new FileDialog(new Frame(),\"选择传送的文件\",FileDialog.LOAD);
            fdlg.setVisible(true);
            t.setText(fdlg.getDirectory()+fdlg.getFile());
            filename=fdlg.getFile();
            pathname=t.getText();
        }
        else
        {
            if(pathname.equals(\"\")||pathname.equals(\"nullnull\"))
                {
                    JOptionPane.showMessageDialog(null,\"没有选择发送的文件\",\"错误\",JOptionPane.ERROR_MESSAGE);
                    return;
                }
               
            th=new Thread(this);
            th.start();
        }
    }
}