@startuml participant 商户_merchant participant 商户外部账户merchant_account_out participant 商户系统账户merchant_account_sys 商户_merchant -> 商户外部账户merchant_account_out: 1. 发起支付请求 商户_merchant -> 商户系统账户merchant_account_sys: 1. 发起支付请求 @enduml
