usefulport.java

本程序可在局域网内实现聊天、传送文件功能

package org.tuna.net;

import java.net.*;

public class UsefulPort
{
	public static int[] get(int n)
	{
		try{
			int[] ports = new int[n];
			for(int i = 0; i < n; i++){
				DatagramSocket ds = new DatagramSocket();
			  int port = ds.getLocalPort();
			  ds.close();
			  boolean ok = true;
			  for(int j = 0; j < i; j++)
			     if (port == ports[j]){
			       ok = false;
			       break;
			     }
			  if (!ok) continue;
			  ports[i] = port;
			}
			return ports;
		}
		catch(Exception e){
			return null;
		}
	}
	
}