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>