参考博客
http://www.cnblogs.com/lin3615/p/3783272.html
https://github.com/me115/design_patterns
https://design-patterns.readthedocs.io/zh_CN/latest/behavioral_patterns/command.html
参考博客
http://www.cnblogs.com/lin3615/p/3783272.html
https://github.com/me115/design_patterns
https://design-patterns.readthedocs.io/zh_CN/latest/behavioral_patterns/command.html