以最简单的方法实现java绘图板 含画直线，椭圆，橡皮擦的功能~~（学习心得交流"_"_"_"） 说明：总共就这一个java文件-The easiest way to achieve java drawing board with drawing a straight line, oval, eraser function ~ ~ (learn to exchange experience "_"_"_") Descr iption: This is a java file on the tot