修复日志列表取消字段排序时的报错问题

ruoyi-common/src/main/java/com/ruoyi/common/core/page/PageDomain.java

@@ -67,6 +67,7 @@ public class PageDomain
 
     public void setIsAsc(String isAsc)
     {
+        if (StringUtils.isNotEmpty(isAsc)) {
             // 兼容前端排序类型
             if ("ascending".equals(isAsc))
             {
@@ -78,4 +79,5 @@ public class PageDomain
             }
             this.isAsc = isAsc;
         }
+    }
 }