useftpapplet.java

用Java开发FTP代理服务器l05 来自用户的控制进程的标准的FTP命令

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

public class useFtpApplet extends Applet
{
	//属性
    	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="";
        //初始化
    	public void init () 
    	{
    		//设置背景和布局
        	setBackground(Color.white);
        	setLayout(new GridBagLayout());
        	//网袋布局
        	GridBagConstraints GBC = new GridBagConstraints();
        	LblPrompt = new Label("没有连接主机");
        	LblPrompt.setAlignment(Label.LEFT);
		//建立按钮实例
        	BtnConn = new Button("连接");
        	BtnClose = new Button("断开");
        	BtnClose.enable(false);
        	//建立文本域实例
        	TxtUID = new TextField("",15);
        	TxtPWD = new TextField("",15);
        	TxtPWD.setEchoCharacter('*');
        	TxtHost = new TextField("",20);
        	//建立标签实例
        	Label LblUID = new Label("User ID:");
        	Label LblPWD = new Label("PWD:");
        	Label LblHost = new Label("Host:");
		//建立文本框，设置属性
        	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);
        }
	//连接
    	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;
    	}
	// 停止服务
    	public void stop()
    	{
        	try
        	{
            		aftp.closeServer();
        	}
        	catch(IOException e)
        	{}
    	}

    	public void paint(Graphics g){}
	//监听按钮，进行相应处理
    	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()))
            		{	//设置按钮属性
                		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);
    	}
    	//发送文件
    	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");
            			//上载文件
            			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;
    	}
	//显示文件内容
    	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){ }
    	}
    	//主程序
        public static void main(String args[])
        {
        	Frame f = new Frame("FTP Client");
                f.addWindowListener(new WindowAdapter()
                {
                     	public void windowClosing(WindowEvent e)
                     	{	//退出系统
                           	System.exit(0);
                     	}

                });
                useFtpApplet ftp = new   useFtpApplet();
                ftp.init();
                ftp.start();
                f.add(ftp);
                f.pack();
                f.setVisible(true);
       }
}