```[sequence] title:微信支付時序圖 participant 微信支付用戶 as user participant 微信客戶端 as wxc participant 商戶APP客戶端 as appc participant 商戶后臺系統 as apps participant 微信支付系統 as wxs user->appc:1.打開商戶APP客戶端 appc->appc:2.選擇商品下單 appc->apps:3.請求生成訂單 apps->wxs:4.調用統一下單API wxs->wxs:生成預付單 wxs-->apps:5.返回預付單信息 apps->apps:6.生成帶簽名的客戶端支付信息 apps-->appc:7.返回信息 user->appc:8.確認支付 appc-->wxc:9.調起微信支付 wxc->wxs:10.發起支付請求 wxs->wxs:驗證支付參數,APP支付權限 ```