在面板中建立菜单项，开始菜单，记事本的功能，可以在上面输入文字，还有一个计算器的面板，具体功能没有实现，但是是学习JAVA中使用布局管理器的好例子-the panel established menu items, start menu, the function of the notebook, can enter text above, There is also a calculator panel to achieve specific function, but the study is the use of Java layout manager a good example