https://www.zhangxinxu.com/wordpress/2014/07/introduce-svg-sprite-technology/
https://segmentfault.com/a/1190000015367490
https://www.jianshu.com/p/b79271fc53e5
https://blog.csdn.net/j550341130/article/details/54348608
https://www.cnblogs.com/upyun/p/6898791.html
原文：https://www.cnblogs.com/little-ab/p/10445615.html