如何解决XML文件中的警告提示“No grammar constraints (DTD or XML Schema) referenced in the document.”...

解决方法：加上 <!DOCTYPE xml>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xml>
<ROOT>
 <goods>
  <isin>SN100001</isin>
  <quantity>1100</quantity>
  <price>200.20</price>
  <customer>张三</customer>
 </goods>
</ROOT>