Java图形界面作业题
题目要求：
窗体内“单击鼠标左键”，在鼠标处绘制一个“绿圆”
窗体内“单击鼠标右键”，在鼠标处绘制一个“红色方框”
窗体内“双击鼠标左键”，清空所有已画“圆”和“方”(Java graphic interface homework　　　　　 Title requirements:　　　　　 In the form, click the left mouse button, and draw a green circle at the mouse"　　　　　 Click the right mouse button in the form, and draw a red box at the mouse"　　　　　 Double click the left mouse button in the form, empty all the painted circles and squares")