修复导入Excel时字典字段类型为Long转义为空问题

@@ -328,7 +328,7 @@ public class ExcelUtil<T>
                     {
                     {
                         val = Convert.toInt(val);
                         val = Convert.toInt(val);
                     }
                     }
-                    else if (Long.TYPE == fieldType || Long.class == fieldType)
+                    else if ((Long.TYPE == fieldType || Long.class == fieldType) && StringUtils.isNumeric(Convert.toStr(val)))
                     {
                     {
                         val = Convert.toLong(val);
                         val = Convert.toLong(val);
                     }
                     }