//tt test

mallinkCallback/src/main/java/com/iformall/controller/callback/TtWebController.java

@@ -56,7 +56,7 @@ public class TtWebController extends BaseController {
         String event = (String) parameterMap.get("event");
         if("verify_webhook".equals(event)){
             Map content = (HashMap) parameterMap.get("content");
-            String challenge = content.get("challenge").toString();
+            Object challenge = content.get("challenge");
             resultMap.put("challenge", challenge);
             return resultMap;
         }