1，打开pycharm或者idea
2，找到plugins
3，搜索 PlantUML integration
4，安装，重启
5，新建uml文件
6，写代码：
@startuml
participant "APP" as app
participant "server" as server
participant "mysql" as mysql
participant "ES" as es
participant "管理后台" as management
app -> server: 用户下单
server -> mysql: 存储订单信息
mysql -> es: 数据库有更新，更新es
es --> server: 触发定时任务，从ES拉数据
server -> mysql: 回写mysql
mysql -> management: 展示订单数据
@enduml
