基于有限状态机与消息队列的三方支付系统补单实践

{"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，从线下的超市购物到线上的外卖点餐、电商网购等，支付无时无刻不在发生，不论是通过现金、pos 机刷卡还是微信支付宝等第三方支付。线上支付有着及时便捷一气呵成的极致体验，当然也有少数的时候体验不够丝滑，比如早期我们在 PC 版 12306 买火车票，当支付完成后，订单的支付状态却经常不能及时更新，会有一段时间的延迟，有时甚至会等待很长时间处在未支付状态。"}]},{"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":"在支付的过程中由于各种各样的原因（比如外部渠道处理出了问题，异步回调迟迟不来）导致流程走了一半停了下来，用户看到订单依然是未支付状态，会不知所措，此时就需要一种机制来推动完成这笔交易。本文就以三方支付系统中的补单机制为例，来介绍一种较为通用的单据补偿模式。"}]}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":2},"content":[{"type":"text","text":"三方支付系统简介"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}},{"type":"heading","attrs":{"align":null,"level":3},"content":[{"type":"text","text":"1.1 什么是三方支付"}]},{"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":"所谓第三方支付，就是和各大银行签约，独立于商户和银行，具备一定实力和信誉保障的，为商户与消费者提供支付结算服务的第三方独立机构。它是处于买方和卖方之间具备公信力的第三方，承担担保人和资金托管人的角色。三方支付也可以称为虚拟账户支付，由消费者在第三方支付机构开设虚拟账户，并用虚拟账户中的资金进行支付。业界常见的三方支付有支付宝、微信支付、美团支付、京东支付等等。"}]},{"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&支付系统"}]},{"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":"交易是什么，最直观的描述就是“一手交钱、一手交货” ，交易会使买卖双方形成债权和债务关系。"},{"type":"text","marks":[{"type":"strong"}],"text":"交易的存在是支付发生的前提，用户通过使用某种支付方式去完成交易"},{"type":"text","text":"。交易是支付流程的驱动者，根据具体场景组合不同的支付指令，来完成交易资金的转移。"}]},{"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":"支付是交易处理资金流的工具"},{"type":"text","text":"，目的是清偿债权和债务关系；支持多种支付方式（如银行卡支付、余额支付、优惠券组合支付、类似花呗的信用支付等），负责对接账务、会计、计费系统等资金处理能力，接收支付指令，驱动完成资金交换。将实际的支付行为（实际资金）与内部的记账（虚拟资金）相结合，保证虚实一致。"}]},{"type":"paragraph","attrs":{"indent":0,"number":0,"align":null,"origin":null}}]}