无法通过常规验证XML表达式。 XML不是常规语言。

It's not possible to validate XML with regular expressions. XML is not a regular language.

使用XML解析器尝试将字符串解析为XML，或者根据模式验证XML文档，例如 DTD 或 XSD 文件。

Use an XML parser to try to parse the string as XML or else validate the XML document against a schema, for example a DTD or XSD file.