完成一个实现秒表功能的Applet程序。它的GUI界面如下所示： 利用所学的Java语言知识，完成一个实现秒表功能的Applet程序。-Complete a stopwatch function to achieve Applet program. It' s GUI interface is as follows: Java language using the knowledge learned, to complete a stopwatch function to achieve the Applet program.