refactor：增加判断

haoban-manage3-service/src/main/java/com/gic/haoban/manage/service/service/impl/StaffServiceImpl.java

@@ -33,6 +33,9 @@ public class StaffServiceImpl implements StaffService {
 
     @Override
     public TabHaobanStaff selectById(String id) {
+        if (StringUtils.isBlank(id)) {
+            return null;
+        }
         return mapper.selectByPrimaryKey(id);
     }