[活动][修改][传入ID有误返回null]

mallinkService/src/main/java/com/iformall/service/impl/WxActivityServiceImpl.java

@@ -55,6 +55,9 @@ public class WxActivityServiceImpl implements WxActivityService {
     @Override
     public WxActivity getById(Long id) {
         WxActivity wxActivity = wxActivityMapper.selectById(id);
+        if (wxActivity == null) {
+            return null;
+        }
         String html = wxActivity.getHtml();
         if (!StringUtils.isEmpty(html)) {
             try {