Xslt 使用XSL基于唯一节点组合两个xml文件

我有两个文件。数据中有一些重叠，但我想从文件2中提取特定信息并添加到文件1中

File1.xml看起来是这样的：

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <title>This is a book</title>
    <price>$10.00</price>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <title>This is another book</title>
    <price>$20.00</price>
  </book>
</content>

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <year>2011</year>
    <pages>100</pages>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <year>2010</year>
    <pages>200</pages>
  </book>
</content>

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <title>This is a book</title>
    <year>2011</year>
    <pages>100</pages>
    <price>$10.00</price>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <title>This is a another book</title>
    <year>2010</year>
    <pages>200</pages>
    <price>$20.00</price>
  </book>
</content>

111aaa
无名氏
这是一本书
$10.00
111bbb
无名氏
这是另一本书
$20.00

File2.xml看起来是这样的：

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <title>This is a book</title>
    <price>$10.00</price>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <title>This is another book</title>
    <price>$20.00</price>
  </book>
</content>

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <year>2011</year>
    <pages>100</pages>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <year>2010</year>
    <pages>200</pages>
  </book>
</content>

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <title>This is a book</title>
    <year>2011</year>
    <pages>100</pages>
    <price>$10.00</price>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <title>This is a another book</title>
    <year>2010</year>
    <pages>200</pages>
    <price>$20.00</price>
  </book>
</content>

111aaa
无名氏
2011
100
111bbb
无名氏
2010
200

我想从file2中提取year和pages标签，并将其添加到file1中，然后输出一个file3.xml文件，该文件如下所示：

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <title>This is a book</title>
    <price>$10.00</price>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <title>This is another book</title>
    <price>$20.00</price>
  </book>
</content>

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <year>2011</year>
    <pages>100</pages>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <year>2010</year>
    <pages>200</pages>
  </book>
</content>

<content>
  <book>
    <id>111aaa</id>
    <author>John Doe</author>
    <title>This is a book</title>
    <year>2011</year>
    <pages>100</pages>
    <price>$10.00</price>
  </book>
  <book>
    <id>111bbb</id>
    <author>Jane Doe</author>
    <title>This is a another book</title>
    <year>2010</year>
    <pages>200</pages>
    <price>$20.00</price>
  </book>
</content>

111aaa
无名氏
这是一本书
2011
100
$10.00
111bbb
无名氏
这是另一本书
2010
200
$20.00

我正在使用命令行运行xsltproc：

xsltproc transform.xsl file1.xml>file3.xml

我的xsl中有以下代码块，但它只是合并了第一本书的数据。您知道如何编写xsl来浏览每本书吗

<xsl:choose>
                           <xsl:when test="document('file2.xml')/content/book/id = id">
                               <xsl:for-each select="document('file2.xml')/content/book">
                               <xsl:element name="pages">
                               <xsl:value-of select="document('file2.xml')/content/book/pages"/>
                               </xsl:element>
                               <xsl:element name="year">
                                  <xsl:value-of select="document('file2.xml')/content/book/year"/> 
                               </xsl:element>
                                   </xsl:for-each>
                           </xsl:when>
                           <xsl:otherwise></xsl:otherwise>
                       </xsl:choose>

---

我想你在寻找类似的东西。修复语法由您决定

<xsl:for-each select="book">
  <xsl:copy>
    <xsl:apply-templates/>
    <xsl:variable name="id" select="string(id)"/>
    <xsl:for-each select="document('file2.xml')/content/book[string(id)=$id]/*">
      <xsl:apply-templates/><!-- Add in a choose here if you just want to pick out certain fields, or in the for-each above -->
    </xsl:for-each>
  </xsl:copy>
</xsl:for-each>

---

交叉引用要求使用密钥：

<xsl:key name="k1" match="book" use="id"/>

<xsl:template match="@* | node()">
  <xsl:copy>
    <xsl:apply-templates select="@* | node()"/>
  </xsl:copy>
</xsl:template>

<xsl:template match="book">
  <xsl:variable name="id" select="id"/>
  <xsl:apply-templates select="@* | id | author"/>
  <xsl:for-each select="document('file2.xml')">
    <xsl:apply-templates select="key('k1', $id)/year | key('k1', $id)/pages"/>
  </xsl:for-each>
  <xsl:apply-templates select="price"/>
</xsl:template>

---

确保接受最能解决问题的答案。@empo：他不知道“接受答案”是什么意思。