UDP例子得一点问题

[angelcm51]

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

public class UDPReceive
{
	public static void main(String args[])
	{
		try
		{
			if(args.length!=1)
				throw new IllegalArgumentException("Wrong number of args");
			int port=Integer.parseInt(args[0]);
			DatagramSocket dsocket=new DatagramSocket(port);
			byte[] buffer=new byte[2048];
			DatagramPacket packet=new DatagramPacket(buffer,buffer.length);
			for(;;)
			{
				dsocket.receive(packet);
				String msg=new String(buffer,0,packet.getLength());
				System.out.println(packet.getAddress().getHostName()+":"+msg);
				packet.setLength(buffer.length);
			}		
		}
		catch(Exception e)
		{
			System.err.println(e);
		}
	}
}

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

public class UDPSend
{
	public static void main(String args[])
	{
		try
		{
			if(args.length<3)
				throw new IllegalArgumentException("Wrong number of args");
			String host=args[0];
			int port=Integer.parseInt(args[1]);
			byte[] message;
			String msg=args[2];
			message=msg.getBytes();
			InetAddress address=InetAddress.getByName(host);
			DatagramPacket packet=new DatagramPacket(message,
			message.length,address,port);
			DatagramSocket dsocket=new DatagramSocket();
			dsocket.send(packet);
			dsocket.close();
		}
		catch(Exception e)
		{
			System.err.println(e);
		}		
	}
}

javac编译都没问题
java编译运行后都是抛出异常 "Wrong number of args"

怎么回事呢？

[myjava_024]

throw new IllegalArgumentException("Wrong number of args");
throw new IllegalArgumentException("Wrong number of args");
报的这个错误嘛

[云上飞翔]

[Quote=引用楼主 angelcm51 的帖子:]
Java codeimport java.net.InetAddress;
import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class UDPReceive
{
public static void main(String args[])
{
try
{
if(args.length!=1)
throw new IllegalArgumentException("Wrong number of args");
int port=Integer.parseInt(args[0]);
DatagramSocket dso…
[/Quote]
答:你运行程序的方式不对.
1)运行UDPReceive 方式是(设端口号是:9999,IP:192.168.1.177):
java UDPReceive 9999

2)运行UDPSend方式是(设发送给UDPReceive所在的机器的信息是:"你好吗?"):
java UDPSend 192.168.1.177 9999 "你好吗?"

[xiaolong19870717]

要用类 ByteArrayInputStream，和类 ByteArrayOutputStream其中的数据被写入一个 byte 数组

[goodmrning]

ding!

[SylvanLiu]

很明显：
if(args.length!=1)
throw new IllegalArgumentException("Wrong number of args");
....
if(args.length<3)
throw new IllegalArgumentException("Wrong number of args");

参数不对