网上的资源真是海量丫:
https://segmentfault.com/q/1010000000310976
gliffy软件在线网址:https://chrome.google.com/webstore/detail/gliffy-diagrams/bhmicilclplefnflapjmnngmkkkkpfad/related?utm_source=chrome-ntp-launcher
画图后save as png