jbuilder的例子里面就有
D:\JBuilder7\samples\IPWorks\ftp\FTPDemo.jpx

解决方案 »

  1.   

    转别人的,给钱吧Java实现ftp功能(源程序) 
    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="没有连接主机";
                String hostname="";
        public void init () {
            setBackground(Color.white);
            setLayout(new GridBagLayout());
            GridBagConstraints GBC = new GridBagConstraints();
            LblPrompt = new Label("没有连接主机");
            LblPrompt.setAlignment(Label.LEFT);        BtnConn = new Button("连接");
            BtnClose = new Button("断开");
            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("PWD:");
            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("正在连接,请等待.....");
            try{
               aftp =new FtpClient(hostname);
               aftp.login(uid,pwd);
               aftp.binary();
               showFileContents();
            }
            catch(FtpLoginException e){
                a="无权限与主机:"+hostname+"连接!";
                LblPrompt.setText(a);
                return false;
            }
            catch (IOException e){
                a="连接主机:"+hostname+"失败!";
                LblPrompt.setText(a);
                return false;
            }
            catch(SecurityException e)
            {
                a="无权限与主机:"+hostname+"连接!";
                LblPrompt.setText(a);
                return false;
            }
            LblPrompt.setText("连接主机:"+hostname+"成功!");
            return true;
        }    public void stop()
        {
            try
            {
                aftp.closeServer();
            }
            catch(IOException e)
            {
            }
        }    public void paint(Graphics g){
        }    public boolean action(Event evt,Object obj)
        {
            if (evt.target == BtnConn)
            {
                LblPrompt.setText("正在连接,请等待.....");
                if (connect(TxtHost.getText(),TxtUID.getText(),TxtPWD.getText()))
                {
                    BtnConn.setEnabled(false);
                    BtnClose.setEnabled(true);
                }
                return true;
            }
            if (evt.target == BtnClose)
            {
                stop();
                BtnConn.enable(true);
                BtnClose.enable(false);
                LblPrompt.setText("与主机"+hostname+"连接已断开!");
                return true;
            }
            return super.action(evt,obj);
        }
        public boolean sendFile(String filepathname){
            boolean result=true;
            if (aftp != null)
            {
            LblPrompt.setText("正在粘贴文件,请耐心等待....");        String   contentperline;
            try{
                a="粘贴成功!";
                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() < sendFile.length() )
                {
                   ch = sendFile.read();
                   outputs.write(ch);
                }
                outs.close();
                sendFile.close();
            }
            catch(IOException e){
               a = "粘贴失败!";
               result = false ;        }
            LblPrompt.setText(a);
            showFileContents();
            }
            else{
                result = false;
            }
            return result;
        }    public void showFileContents()
        {
            StringBuffer buf = new StringBuffer();
            lsArea.setText("");
            try
            {
                ins= aftp.list();
                while ((ch=ins.read())>=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 Client");
                      f.addWindowListener(new WindowAdapter(){
                         public void windowClosing(WindowEvent e){
                               System.exit(0);
                         }                  });
                      FtpApplet ftp = new   FtpApplet();
                      ftp.init();
                      ftp.start();
                      f.add(ftp);
                      f.pack();
                      f.setVisible(true);
                }
    }  
      

  2.   

    TxtPWD.setEchoCharacter(’*’);可能需要改成
    TxtPWD.setEchoCharacter('*');