bug fix

src/main/java/com/huiju/estateagents/controller/ExtendContentController.java

                 return responseBean;
             }
 
+            if (StringUtils.isEmpty(extendContent.getContentType())){
+                extendContent.setContentType("nothing");
+            }
+
             if (iExtendContentService.updateById(extendContent)){
                 responseBean.addSuccess(extendContent);
             }else {