使用XSLT向XML添加属性和值

<!-- 原始XML文档 -->
<books>
  <book>
    <title>Book 1</title>
    <author>Author 1</author>
  </book>
  <book>
    <title>Book 2</title>
    <author>Author 2</author>
  </book>
</books>

<!-- XSLT样式表 -->
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template match="book">
    <xsl:element name="book">
      <xsl:attribute name="category">Fiction</xsl:attribute>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:element>
  </xsl:template>
  
  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>
</xsl:stylesheet>

<!-- 转换后的XML文档 -->
<books>
  <book category="Fiction">
    <title>Book 1</title>
    <author>Author 1</author>
  </book>
  <book category="Fiction">
    <title>Book 2</title>
    <author>Author 2</author>
  </book>
</books>