1、接入paypal

2、修改支付宝支付

src/main/java/com/ai/da/service/CallBackService.java

@@ -0,0 +1,12 @@
+package com.ai.da.service;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public interface CallBackService {
+
+    Boolean doGet(HttpServletRequest req, HttpServletResponse resp)
+            throws ServletException, IOException;
+}