TCP/UDP By Java

import java.io.*;
import java.net.*;

class TCPServer{
	public static void main(String[] args)throws IOException{
		ServerSocket listen = new ServerSocket(5050);
		
		Socket server  = listen.accept();

		InputStream in = server.getInputStream();
		OutputStream out = server.getOutputStream();

		char c = (char)in.read();
		System.out.println("Get:" + c);

		out.write('s');
		
		out.close();
		in.close();
		server.close();
		listen.close();
	}
}

import java.io.*;
import java.net.*;

class TCPClient{
	public static void main(String[] args)throws IOException{
		Socket client = new Socket("127.0.0.1" , 5050);

		InputStream in = client.getInputStream();
		OutputStream out = client.getOutputStream();
		
		out.write('c');

		char c = (char)in.read();
		System.out.println("�յ�:" + c);

		out.close();
		in.close();
		client.close();
	}
}

import java.io.*;
import java.net.*;

class UDPServer{
	public static void main(String[] args)throws IOException{
		DatagramSocket  server = new DatagramSocket(5050);

		byte[] recvBuf = new byte[100];
		DatagramPacket recvPacket 
			= new DatagramPacket(recvBuf , recvBuf.length);

		server.receive(recvPacket);

		String recvStr = new String(recvPacket.getData() , 0 , recvPacket.getLength());
		System.out.println("Hello World!" + recvStr);

		int port = recvPacket.getPort();
		InetAddress addr = recvPacket.getAddress();
		String sendStr = "Hello ! I'm Server";
		byte[] sendBuf;
		sendBuf = sendStr.getBytes();
		DatagramPacket sendPacket 
			= new DatagramPacket(sendBuf , sendBuf.length , addr , port );

		server.send(sendPacket); 

		server.close();
	}
}

import java.io.*;
import java.net.*;

class UDPClient{
	public static void main(String[] args)throws IOException{
		DatagramSocket client = new DatagramSocket();
		
		String sendStr = "Hello! I'm Client";
		byte[] sendBuf;
		sendBuf = sendStr.getBytes();
		InetAddress addr = InetAddress.getByName("127.0.0.1");
		int port = 5050;
		DatagramPacket sendPacket 
			= new DatagramPacket(sendBuf ,sendBuf.length , addr , port);

		client.send(sendPacket);

		byte[] recvBuf = new byte[100];
		DatagramPacket recvPacket
			= new DatagramPacket(recvBuf , recvBuf.length);
		client.receive(recvPacket);
		String recvStr = new String(recvPacket.getData() , 0 ,recvPacket.getLength());
		System.out.println("�յ�:" + recvStr);

		client.close();
	}
}