// TCP客户端
public class TCPClient{
	public static void main(String args[]) throws Exception{
		// 1.输入服务端IP和端口，下载文件路径
		String ip = args[0];
		int port = Integer.parseInt(args[1]);
		String filePath = args[2];
		Socket socket = new Socket(ip, port);
		// 2.建立TCP连接，发送文件路径
		new DataOutputStream(socket.getOutputStream()).writeUTF(filePath);
		// 3.接收文件名，大小，内容
		DataInputStream sin = new DataInputStream(socket.getInputStream());	
		FileOutputStream fou = new FileOutputStream(System.currentTimeMillis()+"_"+sin.readUTF());		
		long len = sin.readLong();
		int pro=0;  
		int l; 
		byte[] b = new byte[1024*1024];
		while ((l = sin.read(b)) != -1) {
			fou.write(b,0,l);
			pro += l;
			System.out.println("下载大小"+String.format("%.2f",pro/1024f/1024)+"MB, "+
								"进度"+String.format("%.2f",pro*100f/len)+"%"); 
		}       
		sin.close();
		fou.close();
		socket.close();
	}
}

// TCP服务端
public class TCPServer{
	public static void main(String arg[]) throws Exception{
		// 1.输入服务端监听端口
		String port = arg[0];
		ServerSocket serverSocket = new ServerSocket(Integer.parseInt(port)); 
		while (true) {
			// 2.死循环监听端口,等待客户端请求
			System.out.println("正在监听"+port+"端口。。。\n");
			Socket socket = serverSocket.accept();			
			// 3.TCP连接成功，接收客户端请求文件路径
			String filePath = new DataInputStream(socket.getInputStream()).readUTF();
			File file = new File(filePath);
			FileInputStream fin = new FileInputStream(file);
			System.out.println("TCP连接成功，客户端请求文件路径"+filePath);            
			// 4.发送文件
			DataOutputStream sou = new DataOutputStream(socket.getOutputStream());			
			sou.writeUTF(file.getName());				
			sou.writeLong(file.length());			
			byte[] b = new byte[1024*1024];
			int l;
			while ((l = fin.read(b)) != -1) {
				sou.write(b, 0, l);
				System.out.println("正在发送文件。。。");
			}
			System.out.println("文件发送完成\n");         
			fin.close();
			sou.close();
			socket.close();
		}
	}
}
	

// UDP客户端
public class UDPClient{
	public static void main(String[] args)throws IOException{
		// 1.直接发数据(不建立连接)
		DatagramSocket dsocket = new DatagramSocket();
		byte[] sen = "你好!我是UDP客户端".getBytes("utf-8");
		dsocket.send(new DatagramPacket(sen,sen.length,InetAddress.getByName("localhost"),9999));
		System.out.println("客户端发送");
		// 2.接收数据
		DatagramPacket rec = new DatagramPacket(new byte[100],100);
		dsocket.receive(rec);	
		dsocket.close();
		System.out.println("客户端接收:" + new String(rec.getData(),0,rec.getLength()));
	}
}

// UDP服务端
public class UDPServer{
	public static void main(String[] args)throws IOException{			
		DatagramSocket dsocket = new DatagramSocket(9999);
		DatagramPacket rec = new DatagramPacket(new byte[100], 100);			
		while (true) {
			// 1.监听端口
			System.out.println("监听等待...");
			dsocket.receive(rec);   // 线程等待, 直到接收到消息				
			// 2.接收数据
			System.out.println("服务端接收:"+new String(rec.getData(), 0, rec.getLength()));
			// 3.发送数据
			byte[] sec = "你好!我是服务端".getBytes("utf-8");
			dsocket.send(new DatagramPacket(sec, sec.length, rec.getAddress(), rec.getPort()));
			System.out.println("服务端响应!");
		}
}