TCP/UDP与Socket

OSI七层与TCP/IP4层

TCP/IP4层	OSI七层	协议
应用层	应用层	Telnet、FTP、HTTP、DNS、SMTP、POP3
表示层
会话层
传输层	传输层	TCP、UDP
网络层	网络层	IP、ICMP、IGMP
网络接口层	数据链路层
物理层

 

 

 

 

 

 

 

 

 

 

 

 

 

TCP与UDP比较

	TCP	UDP
是否连接	面向连接的	面向非连接的
传输可靠性	可靠的	不可靠的
应用场合	1、数据完整性要求高的传输 2、传输大量的数据（大小没有限制） 如：安装文件下载等	1、实时性要求高，丢失部分数据也无关紧要的传输 2、少量数据（有限制，每次不超过64K） 如：视频会议等
速度	慢	快

 

 

 

 

 

 

 

 

 

 

Socket与TCP、UDP

1、TCP实现

package myjava.net.socket.tcp;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * Dependent on TCP protocol<br>
 * 1.MultiThread for server socket.<br>
 * 2.Create a new thread when accept a client socket.<br>
 * 
 * @author jeck.xie 2009-3-25
 */
public class SocketTCP extends Thread {
	private Socket s;

	public SocketTCP(Socket s) {
		this.s = s;
	}

	@Override
	public void run() {
		try {
			OutputStream os = s.getOutputStream();
			InputStream is = s.getInputStream();
			os.write("Hello,welcome you!".getBytes());
			byte[] buf = new byte[100];
			int len = is.read(buf);
			System.out.println(new String(buf, 0, len));
			os.close();
			is.close();
			s.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
		if (args.length > 0)
			server();
		else
			client();
	}

	public static void server() {
		try {
			ServerSocket ss = new ServerSocket(6000);
			while (true) {
				Socket s = ss.accept();
				new SocketTCP(s).start();
			}

			// ss.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public static void client() {
		try {
			Socket s = new Socket(InetAddress.getLocalHost(), 6000);
			OutputStream os = s.getOutputStream();
			InputStream is = s.getInputStream();
			byte[] buf = new byte[100];
			int len = is.read(buf);
			System.out.println(new String(buf, 0, len));
			os.write("Hello,this is zhangsan!".getBytes());
			os.close();
			is.close();
			s.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

 2.UDP实现

package myjava.net.socket.udp;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

/**
 * Dependent on UDP protocol<br>
 * 
 * @author jeck.xie 2009-3-25
 */
public class SocketUDP {

	public static void main(String[] args) {
		if (args.length > 0)
			recv();
		else
			send();
	}

	public static void recv() {
		try {
			DatagramSocket ds = new DatagramSocket(6000);

			// accept data
			byte[] buf = new byte[100];
			DatagramPacket dp = new DatagramPacket(buf, 100);
			ds.receive(dp);
			System.out.println(new String(buf, 0, 100));

			// send data
			String str = "Welcome you!";
			DatagramPacket dpSend = new DatagramPacket(str.getBytes(), str
					.length(), dp.getAddress(), dp.getPort());
			ds.send(dpSend);

			ds.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void send() {
		try {
			DatagramSocket ds = new DatagramSocket();

			// send data
			String str = "Hello, this is zhangsan!";
			DatagramPacket dp = new DatagramPacket(str.getBytes(),
					str.length(), InetAddress.getLocalHost(), 6000);
			ds.send(dp);

			// accept data
			byte[] buf = new byte[100];
			DatagramPacket dbRecv = new DatagramPacket(buf, 100);
			ds.receive(dbRecv);
			System.out.println(new String(buf, 0, 100));

			ds.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}