import java.net.*;import java.io.*;import java.util.Date; public class useTimeServer { 	//設置常數屬性  	public final static int DEFAULT_PORT = 37;		//主程序  	public static void main(String[] args)   	{          		//設置缺省端口   		int port = DEFAULT_PORT;        		if (args.length > 0)    		{     			try      			{     				//從參數中獲取端口信息        			port = Integer.parseInt(args[0]);        			//判斷端口輸入是否正確        			if (port < 0 || port >= 65536)         			{          				System.out.println("Port must between 0 and 65535");          				return;              			}     			}        			//捕獲異常     			catch (NumberFormatException e) {}     		}        		// 時間協議設置從1900年開始紀年   		//java Date類從1970年開始紀年    		// 在當中要進行數量轉換    		//設置轉換常量   		long differenceBetweenEpochs = 2208988800L;       		try    		{   			//建立ServerSocket     			ServerSocket server = new ServerSocket(port);     			//服務一直運行       			while (true)        			{       				Socket connection = null;         			try          			{         				//建立Socket連接           				connection = server.accept();           				//建立輸出流對象           				OutputStream out = connection.getOutputStream();           				//新建時間對象           				Date now = new Date();           				//獲取時間           				long msSince1970 = now.getTime();           				long secondsSince1970 = msSince1970/1000;           				//處理紀年差異           				long secondsSince1900 = secondsSince1970+ differenceBetweenEpochs;           				//獲取符合Time協議的時間值           				byte[] time = new byte[4];           				time[0]= (byte) ((secondsSince1900 & 0x00000000FF000000L) >> 24);           				time[1]= (byte) ((secondsSince1900 & 0x0000000000FF0000L) >> 16);           				time[2]= (byte) ((secondsSince1900 & 0x000000000000FF00L) >> 8);           				time[3] = (byte) (secondsSince1900 & 0x00000000000000FFL);           				//輸出時間值           				out.write(time);           				out.flush();               			} // end try         			catch (IOException e)          			{} // end catch         			finally          			{         				//關閉連接           				if (connection != null) connection.close();          			}       			}  // end while   		}  // end try   		catch (IOException e)    		{     			System.err.println(e);   		} // end catch  	} // end main} // end useTimeServer