udpclient.java

UDP一对一通信

import java.io.*;
import java.net.*;
public class udpclient
{
	public static void main(String[] args) throws IOException
	{
		DatagramSocket clientsoc=null;//客户的socket
		DatagramPacket clientpac=null;//客户发出去的数据包
		DatagramPacket clientrecpac=null;//客户从服务器上接收的数据包
		String strToSend=null;//要发给服务器的数据
		String data=null;//接收的字节流
		byte[] buf=null;//发送的字节流
		byte[] buf1=null;//发送的最后一个字节流
		byte[] bufrec=null;//接收的字节流
		DataInputStream sysin=null;//客户的输入流
		try
		{
			bufrec=new byte[256];
			clientsoc=new DatagramSocket();
			sysin=new DataInputStream(System.in);
			strToSend=sysin.readLine();
			while(strToSend!="quit")
			{
				buf=new byte[strToSend.length()];
				strToSend.getBytes(0,buf.length,buf,0);
				clientpac=new DatagramPacket(buf,buf.length,InetAddress.getByName("localhost"),9000);
				clientsoc.send(clientpac);
				clientrecpac=new DatagramPacket(bufrec,bufrec.length);
				clientsoc.receive(clientrecpac);
				data=new String(bufrec,0,0,bufrec.length);
				System.out.println("Server said:"+data);
				strToSend=sysin.readLine();
					
			}	
			buf1=new byte[strToSend.length()];
			strToSend.getBytes(0,buf1.length,buf1,0);
			clientpac=new DatagramPacket(buf1,buf1.length,InetAddress.getByName("localhost"),9000);
			clientsoc.send(clientpac);
		}
		catch(Exception e)
		{
			System.out.println("Error:"+e);	
		}
		finally
		{
		clientsoc.close();
		System.exit(0);
		}
	}	
}