反射获取Class对象

https://www.cnblogs.com/tech-bird/p/3525336.html（copy）

https://blog.csdn.net/lwl20140904/article/details/80163880

https://www.cnblogs.com/buoge/p/9285142.html

https://www.cnblogs.com/hellowhy/p/7768202.html

 实际演示