public void sendMessage(StringBuilder message){
		try {
			for (int i=0;i<clients.size();i++){
				Vclient c=clients.get(i);
				c.dos.writeUTF(message.toString());
			}
		} catch (NullPointerException e) {
			System.out.println("发送信息失败");
		} catch (IOException e) {
			System.out.println("发送失败！");
		}
	}