FileInputStream fis = new FileInputStream(file);
						OutputStream os = dataSocket.getOutputStream();


						byte [] buffer = new byte[1024];
						int byteread = 0;
						while((byteread = fis.read(buffer))!=-1){
							os.write(buffer, 0, byteread);
						}
						fis.close();
						os.close();
					}
				}else{ //目标是文件
					file = new File(address);
					server_downloadFile(s, 0);
				}

			}






			/***
			 * REST
			 */
			else if(order.equals("REST")){
				//指定偏移位置
				int len = Integer.parseInt(msg.substring(4).trim());
				dos.writeUTF("350 Rest supported. Restarting at " + len);
				//读取RETR指令
				msg = dis.readUTF();
				String address = msg.substring(4).trim();
				file = new File(address);
				server_downloadFile(s, len);
			}

			else if(order.equals("SIZE")){
				String address = msg.substring(4).trim();
				File file = new File(address);
				if(file.exists()){	//服务器存在此文件
					dos.writeUTF("exists");
					dos.writeUTF(Long.toString(file.length()));
				}
				else{
					dos.writeUTF("服务器不存在此文件");
				}

			}




			/***
			 * 切换目录
			 */
			else if(order.equals("CWD")){
				String newPath = msg.substring(3).trim();
				path = newPath;
			}



			/***
			 * STOR
			 */
			else if(order.equals("STOR")){
				String address=msg.substring(4).trim();
				File tmpFile=new File("D:\\ftp\\" + address);
				if(tmpFile.exists()){
					String str=dis.readUTF();
					if(str.equals("exists")){ //断点续传
						int len=Integer.parseInt(Long.toString(tmpFile.length()));
						byte[] bytes=new byte[1024];
						InputStream is=dataSocket.getInputStream();
						FileOutputStream fos=new FileOutputStream(tmpFile,true);
						int length=0;
						while((length=is.read(bytes))!=-1){
							fos.write(bytes, len, length);
						}
						System.out.println("上传成功1");
						is.close();
						fos.close();
					}else{
						System.out.println("客户端:"+str);
					}
				}else{
					String str=dis.readUTF();
					if(str.equals("exists")){
						byte[] bytes=new byte[1024];
						InputStream is=dataSocket.getInputStream();
						FileOutputStream fos=new FileOutputStream(tmpFile);
						int length=0;
						while((length=is.read(bytes))!=-1){
							fos.write(bytes, 0, length);
						}
						System.out.println("上传成功2");
						fos.close();
						is.close();
					}else{
						System.out.println("客户端:"+str);
					}
				}

			}







			else if(order.equals("QUIT")){
				dos.writeUTF("221 Goodbye");
				s.close();
				ds.close();
				return;
			}


		}
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}

}


/***
 * 下载单个文件
 */

public static void server_downloadFile(Socket s, int len) throws IOException{
	DataInputStream dis = new DataInputStream(s.getInputStream());
	DataOutputStream dos = new DataOutputStream(s.getOutputStream());
	FileInputStream fis = new FileInputStream(file);
	OutputStream os = dataSocket.getOutputStream();
	if(file.exists()){
		dos.writeUTF("exists"); //服务器存在此文件
		byte [] buffer = new byte[1024];
		int byteread = 0;
		while((byteread = fis.read(buffer))!=-1){
			os.write(buffer, len, byteread);
		}
		fis.close();
		os.close();

	}else {
		dos.writeUTF("服务器不存在此文件");
	}
}

public static void main(String[] args) {
	// TODO Auto-generated method stub
	//1.打开一个监听端口
	try {
		ServerSocket ss = new ServerSocket(3336);
		while(true){
			//2. 接受客户端的访问
			Socket s = ss.accept();
			//3.启动子线程，把s传递给子线程
			TaskThread tt = new TaskThread(s);
			//4.启动子线程
			tt.start(); //tt线程准备就绪,不能直接调用run方法
		}

	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
}

	} catch (UnknownHostException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
}


/**
* 建立FTP连接
*/
public static void connectFTP(Socket s) throws IOException{
	DataInputStream dis=new DataInputStream(s.getInputStream());
	DataOutputStream dos=new DataOutputStream(s.getOutputStream());
	//String username = "livc";
	//String password = "rt";

	System.out.println("请输入账号：");
	String username = scanner.nextLine();
	dos.writeUTF("USER "+ username);
	dos.flush();
	reponse = dis.readUTF();
	System.out.println("服务器消息：" + "\n" + reponse); //331 Password required for livc95

	while(true){ //直到输入正确的密码
		System.out.println("请输入密码：");
		String password = scanner.nextLine();
		dos.writeUTF("PASS "+ password);
		dos.flush();
		reponse = dis.readUTF();
		System.out.println("服务器消息：" + "\n" + reponse); //230 Logged on
		if(reponse.substring(0, 3).equals("230"))
			break;
	}


	dos.writeUTF("PASV");
	dos.flush();
	reponse = dis.readUTF(); // 227 entering passive mode (h1,h2,h3,h4,p1,p2)
	System.out.println(reponse);

	//从字符串中取出 p1和p2
	int cnt = 0, p1 = 0, p2 = 0;
	for(int i = 0; i < reponse.length(); i++){
		char c = reponse.charAt(i);
		if(cnt == 4 && c != ','){
			p1 = p1*10+c-'0';
		}
		if(cnt == 5 && c != ',' && c != ')'){
			p2 = p2*10+c-'0';
		}
		if(c == ',') cnt++;
	}
	//System.out.println("p1: " + p1 + " p2: " + p2);
	port1 = p1*256+p2;

}



/**
* 关闭FTP连接
*/
public static void closeFTP(Socket s) throws IOException{
	DataInputStream dis = new DataInputStream(s.getInputStream());
	DataOutputStream dos = new DataOutputStream(s.getOutputStream());
	dos.writeUTF("QUIT");
	dos.flush();
	reponse = dis.readUTF();
	System.out.println(reponse); //221 Goodbye
}



/**
* 获取文件列表
*/
public static void list(Socket s, Socket dataSocket) throws IOException{
	DataInputStream dis=new DataInputStream(s.getInputStream());
	DataOutputStream dos=new DataOutputStream(s.getOutputStream());
	dos.writeUTF("List D:\\ftp\r\n");
	dos.flush();
	reponse = dis.readUTF();
	System.out.println(reponse); //输出文件列表
	reponse = dis.readUTF();
	System.out.println(reponse); //226 Transfer OK
}



/**
* 下载文件
*/
public static void downloadFile(Socket s, Socket dataSocket, String remoteFile) throws IOException{
	DataInputStream dis = new DataInputStream(s.getInputStream());
	DataOutputStream dos = new DataOutputStream(s.getOutputStream());
	//System.out.println("请输入要下载的文件名");

	System.out.println("请输入文件保存名");
	localFile = scanner.nextLine();
	File file = new File("D:\\ftp\\" + localFile);

	if(file.exists()){  //文件存在，断点续传

		int len = (int)file.length();  //本地文件长度
		dos.writeUTF("REST " + len); //从指定点重新开始传输
		dos.flush();
		reponse = dis.readUTF();
		System.out.println(reponse);//350 Rest supported. Restarting at 0


		System.out.println("断点续传下载中");

		dos.writeUTF("RETR " + remoteFile);
		dos.flush();
		reponse = dis.readUTF(); //吃掉返回来的exists
		byte[] bytes = new byte[1024];
		InputStream is = dataSocket.getInputStream();
		FileOutputStream fos=new FileOutputStream(file);
		int length = 0;
		while((length = is.read(bytes)) != -1){
			fos.write(bytes, len, length);  //断点续传
		}
		System.out.println("断点续传下载成功");
		fos.close();
		is.close();

	}else{

		dos.writeUTF("RETR " + remoteFile);
		dos.flush();
		String str = dis.readUTF();
		if(str.equals("exists")){ //服务器存在此文件，开始下载
			System.out.println("开始下载");
			byte[] bytes = new byte[1024];
			InputStream is = dataSocket.getInputStream();
			FileOutputStream fos=new FileOutputStream(file);
			int length = 0;
			while((length = is.read(bytes)) != -1){
				fos.write(bytes, 0, length); //分别代表缓冲源、数据偏移开始位置、要写入字节数
			}
			System.out.println("下载成功");
			fos.close();
			is.close();

		}else{ //服务器不存在此文件
			System.out.println("服务器:"+str);
		}

	}
}



/**
* 下载文件夹
*/
public static void downloadFolder(Socket s, Socket dataSocket, String downloadFolder) throws IOException{
	DataInputStream dis = new DataInputStream(s.getInputStream());
	DataOutputStream dos = new DataOutputStream(s.getOutputStream());
	//System.out.println("请输入要下载的文件名");

	//System.out.println("请输入文件保存名");
	//localFile = scanner.nextLine();
	//File file = new File("D:\\ftp\\" + localFile);

	dos.writeUTF("RETR " + remoteFolder);
	dos.flush();
	File file = new File("D:\\down"); //下载到这个文件夹
	if(!file.exists()){//如果不存在该文件夹
		file.mkdir();//新建
		int numofFile = dis.read(); //下载文件内文件夹的个数

		System.out.println(numofFile);

		for(int i = 0; i < numofFile; i++){
			reponse = dis.readUTF(); //每个文件名
			remoteFile = "D:\\down\\" + reponse;
			//System.out.println(remoteFile);

			//下载文件夹内单个文件
			dos.writeUTF("RETR " + remoteFile);
			dos.flush();
			//String str = dis.readUTF();

			System.out.println("开始下载");
			byte[] bytes = new byte[1024];
			InputStream is = dataSocket.getInputStream();
			FileOutputStream fos=new FileOutputStream(file);
			int length = 0;
			while((length = is.read(bytes)) != -1){
				fos.write(bytes, 0, length); //分别代表缓冲源、数据偏移开始位置、要写入字节数
			}
			System.out.println("第"+(i+1)+"个文件下载成功");
			fos.close();
			is.close();


		}

	}

}



/**
* 上传文件
*/
public static void uploadFile(Socket s, Socket dataSocket, String localFile) throws IOException{
	DataInputStream dis = new DataInputStream(s.getInputStream());
	DataOutputStream dos = new DataOutputStream(s.getOutputStream());

	//输入被上传文件名字
	System.out.println("已建立连接，请输入上传文件名：");
	String namesh=scanner.nextLine();
	dos.writeUTF("STOR "+namesh);
	File file2 = new File("D:\\ftp\\down\\"+namesh);
	if(file2.exists()){
		dos.writeUTF("exists");
		FileInputStream fis=new FileInputStream(file2);
		OutputStream os=dataSocket.getOutputStream();
		byte [] buffer=new byte[1024];
		int byteread=0;
		while((byteread=fis.read(buffer))!=-1){
			os.write(buffer, 0, byteread);
		}
		fis.close();
		os.close();
	}else{
		dos.writeUTF("file don't exists");
	}
}