fixbug

@@ -185,9 +185,9 @@ public abstract class AbstractWeixinPayService extends AbstractPayService {
     }
 
     protected Map<String, String> withHmacSha256Sign(Map<String, String> signParams){
+        signParams.put(WeixinPayConfig.ApiConstants.SIGN_TYPE, "HMAC-SHA256");
         String sign = hmacSha256(signParams);
         signParams.put(WeixinPayConfig.ApiConstants.SIGN, sign);
-        signParams.put(WeixinPayConfig.ApiConstants.SIGN_TYPE, "HMAC-SHA256");
         return signParams;
     }