支付宝文档：https://doc.open.alipay.com/doc2/detail?treeId=62&articleId=103566&docType=1
支付宝提供DEMO
具体如何处理回调根据业务需求处理即可。
回调结果如下：
buyer_id==2088412440119763
trade_no==2015101900001000760062319390
body==屌丝啊
notify_time==2015-10-19 18:21:48
use_coupon==N
subject==一个月
sign_type==RSA
is_total_fee_adjust==N
notify_type==trade_status_sync
/*唯一订单号*/
out_trade_no==101918213513153
trade_status==TRADE_SUCCESS
gmt_payment==2015-10-19 18:21:48
discount==0.01
sign==VRMEy7D/3OmfVYMNcX9iZB0XqxIoWOWAbfyTesCeG2EhPdzkhbFYxVf2WyVrvnvzci1/kPau+YiieHt3m9mU1/qH6PbxF6Qlnu27GbRutf07kIJw+vI26JzgRWE2stF4YjAlWkISkk6sUkjj8IO0rDAtxMgPcKinOWwnoMDJVFQ=
buyer_email==134*******
gmt_create==2015-10-19 18:21:48
price==0.01
total_fee==0.01
quantity==1
seller_id==2088*************
seller_email==*******@**.com
notify_id==6cbceb25b0093ec64bd58734b50f3c6668
payment_type==1