Weather() {	//ʾ
		try {
				iaddress=InetAddress.getByName("224.255.10.0");	//ʵinetaddress
				socket=new MulticastSocket(port);	//
				socket.setTimeToLive(1);	//ָͷΧǱ
				socket.joinGroup(iaddress);	//㲥
		}catch(Exception e){
			e.printStackTrace();
		}
	}