基於有限狀態機與消息隊列的三方支付系統補單實踐

{"type":"doc","content":[{"type":"blockquote","content":[{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"引言：在日常生活中，從線下的超市購物到線上的外賣點餐、電商網購等，支付無時無刻不在發生，不論是通過現金、pos 機刷卡還是微信支付寶等第三方支付。線上支付有着及時便捷一氣呵成的極致體驗，當然也有少數的時候體驗不夠絲滑，比如早期我們在 PC 版 12306 買火車票，當支付完成後，訂單的支付狀態卻經常不能及時更新，會有一段時間的延遲，有時甚至會等待很長時間處在未支付狀態。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"在支付的過程中由於各種各樣的原因（比如外部渠道處理出了問題，異步回調遲遲不來）導致流程走了一半停了下來，用戶看到訂單依然是未支付狀態，會不知所措，此時就需要一種機制來推動完成這筆交易。本文就以三方支付系統中的補單機制爲例，來介紹一種較爲通用的單據補償模式。"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"三方支付系統簡介"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"1.1 什麼是三方支付"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"所謂第三方支付，就是和各大銀行簽約，獨立於商戶和銀行，具備一定實力和信譽保障的，爲商戶與消費者提供支付結算服務的第三方獨立機構。它是處於買方和賣方之間具備公信力的第三方，承擔擔保人和資金託管人的角色。三方支付也可以稱爲虛擬賬戶支付，由消費者在第三方支付機構開設虛擬賬戶，並用虛擬賬戶中的資金進行支付。業界常見的三方支付有支付寶、微信支付、美團支付、京東支付等等。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"1.2 三方支付中的交易&支付系統"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","text":"交易是什麼，最直觀的描述就是“一手交錢、一手交貨” ，交易會使買賣雙方形成債權和債務關係。"},{"type":"text","marks":[{"type":"strong"}],"text":"交易的存在是支付發生的前提，用戶通過使用某種支付方式去完成交易"},{"type":"text","text":"。交易是支付流程的驅動者，根據具體場景組合不同的支付指令，來完成交易資金的轉移。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null},"content":[{"type":"text","marks":[{"type":"strong"}],"text":"支付是交易處理資金流的工具"},{"type":"text","text":"，目的是清償債權和債務關係；支持多種支付方式（如銀行卡支付、餘額支付、優惠券組合支付、類似花唄的信用支付等），負責對接賬務、會計、計費系統等資金處理能力，接收支付指令，驅動完成資金交換。將實際的支付行爲（實際資金）與內部的記賬（虛擬資金）相結合，保證虛實一致。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}