udpclientdemo.java

学习参考,java基本语法练习,包括一些常用的技巧

//基于UDP的客户端程序演示
import java.net.*;
import java.io.*;
public class UDPClientDemo{
private DatagramSocket s;
private InetAddress hostAddress;
private byte[] buf = new byte[1000];
private DatagramPacket dp = new DatagramPacket(buf,buf.length);
public UDPClientDemo()
{
	try
	{
		//使用构造器，创建使用本机任何可用端口的数据包Socket
       	s = new DatagramSocket();
       	//获取本地IP
       	hostAddress = InetAddress.getByName("localhost");
       	System.out.println("Client start......");
       	while(true)
       	{
			String strOutMess ="";  
        	//读取输入
         	BufferedReader stdin  = new BufferedReader(new InputStreamReader(System.in));
         	try
         	{
           		strOutMess = stdin.readLine();
         	}catch(IOException ie)
         	{
           		System.err.println("IO error!");
         	}
         	//如果输入“bye”则表示退出程序
         	if(strOutMess.equals("bye")) break;
         	String strOut = "[Client say]: "+ strOutMess;
         	byte[] buf = strOut.getBytes();
         	//打包数据，发送数据
         	DatagramPacket out = new DatagramPacket(buf,buf.length,hostAddress,ChatServer.PORT);
         	s.send(out);
         	//等待服务器返回
         	s.receive(dp);
         	String strReceived = "("+ dp.getAddress() + ":" + dp.getPort()+")" + 
         	new String(dp.getData(),0,dp.getLength());
         	System.out.println(strReceived);
      }
     }catch(UnknownHostException e)
     {
		System.out.println("未找到服务器!");
		System.exit(1);
     }catch(SocketException e)
     {
		System.out.println("打开套接字错误!");
		e.printStackTrace();
		System.exit(1);
     }catch(IOException e)
     {
		System.err.println("数据传输错误!");
		e.printStackTrace();
		System.exit(1);
     }
 }
	public static void main(String[] args)
	{
		new UDPClientDemo();
	}
}