package ftpapplet;

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

/**
 * 

Title: 

 * 

Description: 

 * 

Copyright: Copyright (c) 2002

 * 

Company: 

 * @author unascribed
 * @version 1.0
 */

//package jdeveloper.ftp;

import sun.net.ftp.*;
import sun.net.*;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;

import java.io.*;

public class FtpApplet extends Applet
{
 FtpClient aftp;
 DataOutputStream outputs;
 TelnetInputStream ins;
 TelnetOutputStream outs;
 TextArea lsArea;
 Label LblPrompt;
 Button BtnConn;
 Button BtnClose;
 TextField TxtUID;
 TextField TxtPWD;
 TextField TxtHost;
 int ch;
 public String a="cannot connect to Host";
                 String hostname="";

 public void init ()
 {
         setBackground(Color.white);
         setLayout(new  GridBagLayout());
         GridBagConstraints GBC=new GridBagConstraints();
         LblPrompt=new Label("can not connect to host");
         LblPrompt.setAlignment(Label.LEFT);

         BtnConn= new Button ("connect");
         BtnClose=new Button ("disconnect");
         BtnClose.enable(false);
         TxtUID= new TextField("",15);
         TxtPWD= new TextField("",15);
         TxtPWD.setEchoCharacter('*');
         TxtHost = new TextField("",20);
         Label LblUID= new Label("User ID:");
         Label LblPWD= new Label("PWS");
         Label LblHost =new Label("Host");

         lsArea= new TextArea(30,80);
         lsArea.setEditable(false);

         GBC.gridwidth=GridBagConstraints.REMAINDER;
         GBC.fill=GridBagConstraints.HORIZONTAL;
         ((GridBagLayout)getLayout()).setConstraints(LblPrompt,GBC);
         add(LblPrompt);

         GBC.gridwidth=1;
         ( (GridBagLayout)getLayout()).setConstraints(LblHost,GBC)  ;
         add(LblHost);
         GBC.gridwidth=GridBagConstraints.REMAINDER;
         ((GridBagLayout)getLayout()).setConstraints(TxtHost,GBC);
         add(TxtHost);

         GBC.gridwidth=1;
         ((GridBagLayout)getLayout()).setConstraints(LblUID,GBC);
         add(LblUID);
         GBC.gridwidth=1;
         ((GridBagLayout)getLayout()).setConstraints(TxtUID,GBC);
         add(TxtUID);

         GBC.gridwidth=1;
         ((GridBagLayout)getLayout()).setConstraints(LblPWD,GBC);
         add(LblPWD);
         GBC.gridwidth=1;
         ((GridBagLayout)getLayout()).setConstraints(TxtPWD,GBC);
         add(TxtPWD);

         GBC.gridwidth=1;
         GBC.weightx=2;
         ((GridBagLayout)getLayout()).setConstraints(BtnConn,GBC);
         add(BtnConn);
         GBC.gridwidth=GridBagConstraints.REMAINDER;

         ((GridBagLayout)getLayout()).setConstraints(BtnClose,GBC);
         add(BtnClose);

         GBC.gridwidth=GridBagConstraints.REMAINDER;
         GBC.fill=GridBagConstraints.HORIZONTAL;
         ((GridBagLayout)getLayout()).setConstraints(lsArea,GBC);
         add(lsArea);
 }


 public boolean connect(String hostname ,String UID,String pwd)
 {
         this.hostname=hostname;
         LblPrompt.setText("connecting ,please waiting ");
         try
         {
           aftp=new FtpClient(hostname);
           aftp.login(UID,pwd);
           aftp.binary();
           showFileContents();
         }
          catch (FtpLoginException e)
           {
            a="no private to "+hostname+"connecting";
            LblPrompt.setText(a);
            return false;
            }
             catch (IOException e)
             {
                     a="connecting"+hostname+"failed";
                     LblPrompt.setText(a);
                     return false;
              }

             catch (SecurityException e)
             {
                     a="no private to "+hostname+"connecting";
                     LblPrompt.setText(a);
                     return false;
             }

         LblPrompt.setText("connecting"+hostname+"sucess");
         return true;
}

         public void paint(Graphics g)
         {
         }

         public boolean action(Event evt,Object obj)
         {
                 if (evt.target==BtnConn)
                 {
                         LblPrompt.setText("connecting ,please waiting ");

                         if (connect(TxtHost.getText(),TxtUID.getText(),TxtPWD.getText()))
                         {
                                 BtnConn.setEnabled(false);
                                 BtnClose.setEnabled(true);
                         }
                                 return true;
                 }

                 return super.action(evt,obj);   //super 指代什么？？
         }





         public boolean sendFile(String filepathname)
         {
                 boolean result=true;
                 if (aftp!=null)
                 {
                         LblPrompt.setText("please be patient,now is pasting");

                         String contentperline;
                         try
                         {
                                 a="paste sucess";
                                 String fg= new String ("\");
                                 int index= filepathname.lastIndexOf(fg);
                                 String filename=filepathname.substring(index+1);
                                 File localFile;
                                 localFile =new File (filepathname);
                                 RandomAccessFile sendFile =new RandomAccessFile(filepathname,"r");
                                 //
                                 sendFile.seek(0);
                                 outs=aftp.put(filename);
                                 outputs =new DataOutputStream(outs);
                                         while (sendFile.getFilePointer()=0)
                         {
                                 buf.append((char)ch);
                         }

                         lsArea.appendText(buf.toString());
                         ins.close();
                 }
                 catch (IOException e)
                 {
                 }
         }


         public static void main(String args[])
         {
                 Frame f=new Frame("FTP Clinet");
                 f.addWindowListener(new WindowAdapter()
                 {
                         public void windowCloseing(WindowEvent e)
                         {
                                 System.exit(0);
                         }
                 });
                 FtpApplet ftp= new FtpApplet();
                 ftp.init();
                 ftp.start();
                 f.add(ftp);
                 f.pack();
                 f.setVisible(true);
         }
}

super代表基类
return super.action(evt,obj);
用的是递归，也就是自己调用自己