TypeError: 'NoneType' does not support the buffer interface: when Transforming XML using XSLT
TypeError: 'NoneType' does not support the buffer interface: when Transforming XML using XSLT
与相关，我要感谢@Parfait 帮助我使用当前使用的 XSLT 代码为我的项目开发 XSLT 基础。但是，当我 运行 它说的 python 模块时出现错误。
File "nsnindex.py", line 17, in <module>
xmlfile.write(tree_out)
TypeError: 'NoneType' does not support the buffer interface.
总体规划是XPATH直奔第三个子节点
<national_stock_number_cross_reference_index>
并使用该部分中的数据输出到新文件。目前，python 吐出一个 blob 中的所有数据，没有标签，并给我上面的错误。
XML 输入
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<lsar030 xsi:schemaLocation="places" xmlns="place2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<head>
<requester>Guy</requester>
<time>12:23:44 PM</time>
<date>Aug 2, 2016</date>
<eiac>ABC</eiac>
<item_name>Thing</item_name>
<start_lcn>start34</start_lcn>
<alc>00</alc>
<lcn_type>P</lcn_type>
<stop_lcn>AA01AA13AB</stop_lcn>
<useable_on_code>ABC</useable_on_code>
<technical_manual_code>000</technical_manual_code>
<technical_manual_number>15241</technical_manual_number>
<report_format>STUFF</report_format>
<kit_option>45</kit_option>
<part_number_cross_reference_index>true</part_number_cross_reference_index>
<national_stock_number_cross_reference_index>true</national_stock_number_cross_reference_index>
<reference_designation_cross_reference_index>false</reference_designation_cross_reference_index>
<figure_item_number_cross_reference_index>false</figure_item_number_cross_reference_index>
<include_drawings_in_output>No</include_drawings_in_output>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 204</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 205</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 208</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 207</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>11</technical_manual_functional_group_code>
<header> FIGURE 501 </header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>12</technical_manual_functional_group_code>
<header>FIGURE 505</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 201</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 202</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 203/header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 200</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>865/technical_manual_functional_group_code>
<header>FIGURE 503</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>865</technical_manual_functional_group_code>
<header>FIGURE 502</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>865</technical_manual_functional_group_code>
<header>FIGURE 504</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 206/header>
</technical_manual_functional_group_code_header>
<baseline_comparison>false</baseline_comparison>
<usmc_option>No</usmc_option>
</head>
<body>
<repair_parts_list>
<repair_parts_fgc_group>
<repair_part>
<item_number>1</item_number>
<smr>PAFDD</smr>
<cage_code>53711</cage_code>
<reference_number>7102539</reference_number>
<technical_manual_indenture_code>1</technical_manual_indenture_code>
<item_name>DINGLE</item_name>
<useable_on_code>EAU</useable_on_code>
<fully_effective>true</fully_effective>
<quantity>1</quantity>
<qpei>1</qpei>
<figure_number>101</figure_number>
<technical_manual_functional_group_code>0000000000A</technical_manual_functional_group_code>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<system_or_end_item_provisioning_contract_control_number>A1ABC</system_or_end_item_provisioning_contract_control_number>
<plisn>ABCD</plisn>
<effectivity_flag>false</effectivity_flag>
<effectivity_label>BERRY</effectivity_label>
</repair_part>
</repair_parts_fgc_group>
</repair_parts_list>
<part_number_cross_reference_index>
<work_package_sequence_number>0005</work_package_sequence_number>
<part_number_cross_reference>
<reference_number>XXXXXX</reference_number>
<figure_number>1</figure_number>
<item_number>10</item_number>
</part_number_cross_reference>
</part_number_cross_reference_index>
<national_stock_number_cross_reference_index>
<work_package_sequence_number>0001</work_package_sequence_number>
<national_stock_number_cross_reference>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<figure_number>1</figure_number>
<item_number>1</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<figure_number>2</figure_number>
<item_number>4</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<figure_number>3</figure_number>
<item_number>2</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1235</federal_supply_classification>
<national_item_identification_number>111111111</national_item_identification_number>
<figure_number>1</figure_number>
<item_number>1</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1235</federal_supply_classification>
<national_item_identification_number>111111111</national_item_identification_number>
<figure_number>2</figure_number>
<item_number>3</item_number>
</national_stock_number_cross_reference>
</national_stock_number_cross_reference_index><national_stock_number_cross_reference>
<federal_supply_classification>1236</federal_supply_classification>
<national_item_identification_number>212121212</national_item_identification_number>
<figure_number>2</figure_number>
<item_number>3</item_number>
</national_stock_number_cross_reference>
</national_stock_number_cross_reference_index>
</body>
</lsar030>
XSLT 代码：
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="numkey" match="lsar030/body/national_stock_number_cross_reference_index/national_stock_number_cross_reference"
use="concat(federal_supply_classification, national_item_identification_number)"/>
<xsl:template match="lsar030/body/national_stock_number_cross_reference_index">
<xsl:apply-templates select="national_stock_number_cross_reference[generate-id() =
generate-id(key('numkey', concat(federal_supply_classification, national_item_identification_number))[1])]"/>
</xsl:template>
<xsl:template match="lsar030/body/national_stock_number_cross_reference_index/national_stock_number_cross_reference">
<nsnindxrow>
<nsn>
<fsc><xsl:value-of select="federal_supply_classification"/></fsc>
<niin><xsl:value-of select="national_item_identification_number"/></niin>
</nsn>
<xsl:for-each select="key('numkey', concat(federal_supply_classification, national_item_identification_number))">
<callout>
<xsl:attribute name="assocfig"><xsl:value-of select="concat('fig', figure_number)"/></xsl:attribute>
<xsl:attribute name="label"><xsl:value-of select="item_number"/></xsl:attribute>
</callout>
</xsl:for-each>
</nsnindxrow>
</xsl:template>
</xsl:stylesheet>
Python代码：
import lxml.etree as ET
# LOAD XML AND XSL FILES
dom = ET.parse('lsar030.xml')
xslt = ET.parse('XSLTScript.xsl')
# TRANSFORM SOURCE
transform = ET.XSLT(xslt)
newdom = transform(dom)
print(newdom)
# OUTPUT TRANSFORMED TREE TO STRING
tree_out = ET.tostring(newdom, encoding='UTF-8', pretty_print=True, xml_declaration=True)
# OUTPUT STRING TO FILE
xmlfile = open('Output.xml', 'wb')
xmlfile.write(tree_out)
xmlfile.close()
输出
<nsnindxrow>
<nsn>
<fsc>5310</fsc>
<niin>00-880-5978</niin>
</nsn>
<callout assocfig="fig700" label="34">
<callout assocfig="fig701" label="10">
<callout assocfig="fig703" label="9">
</nsnindxrow>
有人知道我做错了什么吗？是我的 XPATH 吗？当根标记只是 <national_stock_number_cross_reference_index> 时，@Parfait 的程序可以正常工作，但一旦我更改路径以匹配更复杂的文件，它就停止正常工作。
XML 中出现了影响 XSLT 转换的两个问题：
- 未声明的名称空间前缀 (
xmlns="place2")，其中 header 中的 xmlns 特殊属性没有冒号分隔标识符。因此，XSLT 必须声明一个前缀。
- 其他元素级别，其中 parent 节点及其上方的兄弟节点
national_stock_number_cross_reference_index 元素必须被解析出来。因此，XSLT 必须使用额外的模板。
考虑遵循调整后的 XSLT，声明一个 doc 前缀，该前缀在所有其他 XPath 表达式中都作为前缀。使用相同的 Python 代码进行处理。
XSLT
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:doc="place2" exclude-result-prefixes="doc">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="numkey" match="doc:national_stock_number_cross_reference"
use="concat(doc:federal_supply_classification, doc:national_item_identification_number)"/>
<xsl:template match="/doc:lsar030">
<xsl:apply-templates select="doc:head"/>
<xsl:apply-templates seect="doc:body"/>
</xsl:template>
<xsl:template match="doc:head"/>
<xsl:template match="doc:body">
<xsl:apply-templates select="doc:national_stock_number_cross_reference_index"/>
</xsl:template>
<xsl:template match="doc:national_stock_number_cross_reference_index">
<nsnindxrows>
<xsl:apply-templates select="doc:national_stock_number_cross_reference[generate-id() =
generate-id(key('numkey', concat(doc:federal_supply_classification, doc:national_item_identification_number))[1])]"/>
<nsnindxrows>
</xsl:template>
<xsl:template match="doc:national_stock_number_cross_reference">
<nsnindxrow>
<nsn>
<fsc><xsl:value-of select="doc:federal_supply_classification"/></fsc>
<niin><xsl:value-of select="doc:national_item_identification_number"/></niin>
</nsn>
<xsl:for-each select="key('numkey', concat(doc:federal_supply_classification, doc:national_item_identification_number))">
<callout>
<xsl:attribute name="assocfig"><xsl:value-of select="concat('fig', doc:figure_number)"/></xsl:attribute>
<xsl:attribute name="label"><xsl:value-of select="doc:item_number"/></xsl:attribute>
</callout>
</xsl:for-each>
</nsnindxrow>
</xsl:template>
</xsl:stylesheet>
输出
（与之前的问题 XML 不同，由于此 XML 的一对 <federal_supply_classification> 和 <national_item_identification_number>，因此只呈现一个标注）.
<?xml version="1.0"?>
<nsnindxrows>
<nsnindxrow>
<nsn>
<fsc>1234</fsc>
<niin>000000000</niin>
</nsn>
<callout assocfig="fig1" label="1"/>
<callout assocfig="fig2" label="4"/>
<callout assocfig="fig3" label="2"/>
</nsnindxrow>
<nsnindxrow>
<nsn>
<fsc>1235</fsc>
<niin>111111111</niin>
</nsn>
<callout assocfig="fig1" label="1"/>
<callout assocfig="fig2" label="3"/>
</nsnindxrow>
<nsnindxrow>
<nsn>
<fsc>1236</fsc>
<niin>212121212</niin>
</nsn>
<callout assocfig="fig2" label="3"/>
</nsnindxrow>
</nsnindxrows>
与
File "nsnindex.py", line 17, in <module>
xmlfile.write(tree_out)
TypeError: 'NoneType' does not support the buffer interface.
总体规划是XPATH直奔第三个子节点
<national_stock_number_cross_reference_index>
并使用该部分中的数据输出到新文件。目前，python 吐出一个 blob 中的所有数据，没有标签，并给我上面的错误。
XML 输入
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<lsar030 xsi:schemaLocation="places" xmlns="place2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<head>
<requester>Guy</requester>
<time>12:23:44 PM</time>
<date>Aug 2, 2016</date>
<eiac>ABC</eiac>
<item_name>Thing</item_name>
<start_lcn>start34</start_lcn>
<alc>00</alc>
<lcn_type>P</lcn_type>
<stop_lcn>AA01AA13AB</stop_lcn>
<useable_on_code>ABC</useable_on_code>
<technical_manual_code>000</technical_manual_code>
<technical_manual_number>15241</technical_manual_number>
<report_format>STUFF</report_format>
<kit_option>45</kit_option>
<part_number_cross_reference_index>true</part_number_cross_reference_index>
<national_stock_number_cross_reference_index>true</national_stock_number_cross_reference_index>
<reference_designation_cross_reference_index>false</reference_designation_cross_reference_index>
<figure_item_number_cross_reference_index>false</figure_item_number_cross_reference_index>
<include_drawings_in_output>No</include_drawings_in_output>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 204</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 205</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 208</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 207</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>11</technical_manual_functional_group_code>
<header> FIGURE 501 </header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>12</technical_manual_functional_group_code>
<header>FIGURE 505</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 201</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 202</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 203/header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 200</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>865/technical_manual_functional_group_code>
<header>FIGURE 503</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>865</technical_manual_functional_group_code>
<header>FIGURE 502</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>865</technical_manual_functional_group_code>
<header>FIGURE 504</header>
</technical_manual_functional_group_code_header>
<technical_manual_functional_group_code_header>
<section>2</section>
<technical_manual_functional_group_code>132</technical_manual_functional_group_code>
<header>FIGURE 206/header>
</technical_manual_functional_group_code_header>
<baseline_comparison>false</baseline_comparison>
<usmc_option>No</usmc_option>
</head>
<body>
<repair_parts_list>
<repair_parts_fgc_group>
<repair_part>
<item_number>1</item_number>
<smr>PAFDD</smr>
<cage_code>53711</cage_code>
<reference_number>7102539</reference_number>
<technical_manual_indenture_code>1</technical_manual_indenture_code>
<item_name>DINGLE</item_name>
<useable_on_code>EAU</useable_on_code>
<fully_effective>true</fully_effective>
<quantity>1</quantity>
<qpei>1</qpei>
<figure_number>101</figure_number>
<technical_manual_functional_group_code>0000000000A</technical_manual_functional_group_code>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<system_or_end_item_provisioning_contract_control_number>A1ABC</system_or_end_item_provisioning_contract_control_number>
<plisn>ABCD</plisn>
<effectivity_flag>false</effectivity_flag>
<effectivity_label>BERRY</effectivity_label>
</repair_part>
</repair_parts_fgc_group>
</repair_parts_list>
<part_number_cross_reference_index>
<work_package_sequence_number>0005</work_package_sequence_number>
<part_number_cross_reference>
<reference_number>XXXXXX</reference_number>
<figure_number>1</figure_number>
<item_number>10</item_number>
</part_number_cross_reference>
</part_number_cross_reference_index>
<national_stock_number_cross_reference_index>
<work_package_sequence_number>0001</work_package_sequence_number>
<national_stock_number_cross_reference>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<figure_number>1</figure_number>
<item_number>1</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<figure_number>2</figure_number>
<item_number>4</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1234</federal_supply_classification>
<national_item_identification_number>000000000</national_item_identification_number>
<figure_number>3</figure_number>
<item_number>2</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1235</federal_supply_classification>
<national_item_identification_number>111111111</national_item_identification_number>
<figure_number>1</figure_number>
<item_number>1</item_number>
</national_stock_number_cross_reference><national_stock_number_cross_reference>
<federal_supply_classification>1235</federal_supply_classification>
<national_item_identification_number>111111111</national_item_identification_number>
<figure_number>2</figure_number>
<item_number>3</item_number>
</national_stock_number_cross_reference>
</national_stock_number_cross_reference_index><national_stock_number_cross_reference>
<federal_supply_classification>1236</federal_supply_classification>
<national_item_identification_number>212121212</national_item_identification_number>
<figure_number>2</figure_number>
<item_number>3</item_number>
</national_stock_number_cross_reference>
</national_stock_number_cross_reference_index>
</body>
</lsar030>
XSLT 代码：
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="numkey" match="lsar030/body/national_stock_number_cross_reference_index/national_stock_number_cross_reference"
use="concat(federal_supply_classification, national_item_identification_number)"/>
<xsl:template match="lsar030/body/national_stock_number_cross_reference_index">
<xsl:apply-templates select="national_stock_number_cross_reference[generate-id() =
generate-id(key('numkey', concat(federal_supply_classification, national_item_identification_number))[1])]"/>
</xsl:template>
<xsl:template match="lsar030/body/national_stock_number_cross_reference_index/national_stock_number_cross_reference">
<nsnindxrow>
<nsn>
<fsc><xsl:value-of select="federal_supply_classification"/></fsc>
<niin><xsl:value-of select="national_item_identification_number"/></niin>
</nsn>
<xsl:for-each select="key('numkey', concat(federal_supply_classification, national_item_identification_number))">
<callout>
<xsl:attribute name="assocfig"><xsl:value-of select="concat('fig', figure_number)"/></xsl:attribute>
<xsl:attribute name="label"><xsl:value-of select="item_number"/></xsl:attribute>
</callout>
</xsl:for-each>
</nsnindxrow>
</xsl:template>
</xsl:stylesheet>
Python代码：
import lxml.etree as ET
# LOAD XML AND XSL FILES
dom = ET.parse('lsar030.xml')
xslt = ET.parse('XSLTScript.xsl')
# TRANSFORM SOURCE
transform = ET.XSLT(xslt)
newdom = transform(dom)
print(newdom)
# OUTPUT TRANSFORMED TREE TO STRING
tree_out = ET.tostring(newdom, encoding='UTF-8', pretty_print=True, xml_declaration=True)
# OUTPUT STRING TO FILE
xmlfile = open('Output.xml', 'wb')
xmlfile.write(tree_out)
xmlfile.close()
输出
<nsnindxrow>
<nsn>
<fsc>5310</fsc>
<niin>00-880-5978</niin>
</nsn>
<callout assocfig="fig700" label="34">
<callout assocfig="fig701" label="10">
<callout assocfig="fig703" label="9">
</nsnindxrow>
有人知道我做错了什么吗？是我的 XPATH 吗？当根标记只是 <national_stock_number_cross_reference_index> 时，@Parfait 的程序可以正常工作，但一旦我更改路径以匹配更复杂的文件，它就停止正常工作。
XML 中出现了影响 XSLT 转换的两个问题：
- 未声明的名称空间前缀 (
xmlns="place2")，其中 header 中的 xmlns 特殊属性没有冒号分隔标识符。因此，XSLT 必须声明一个前缀。 - 其他元素级别，其中 parent 节点及其上方的兄弟节点
national_stock_number_cross_reference_index元素必须被解析出来。因此，XSLT 必须使用额外的模板。
考虑遵循调整后的 XSLT，声明一个 doc 前缀，该前缀在所有其他 XPath 表达式中都作为前缀。使用相同的 Python 代码进行处理。
XSLT
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:doc="place2" exclude-result-prefixes="doc">
<xsl:output method="xml" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="numkey" match="doc:national_stock_number_cross_reference"
use="concat(doc:federal_supply_classification, doc:national_item_identification_number)"/>
<xsl:template match="/doc:lsar030">
<xsl:apply-templates select="doc:head"/>
<xsl:apply-templates seect="doc:body"/>
</xsl:template>
<xsl:template match="doc:head"/>
<xsl:template match="doc:body">
<xsl:apply-templates select="doc:national_stock_number_cross_reference_index"/>
</xsl:template>
<xsl:template match="doc:national_stock_number_cross_reference_index">
<nsnindxrows>
<xsl:apply-templates select="doc:national_stock_number_cross_reference[generate-id() =
generate-id(key('numkey', concat(doc:federal_supply_classification, doc:national_item_identification_number))[1])]"/>
<nsnindxrows>
</xsl:template>
<xsl:template match="doc:national_stock_number_cross_reference">
<nsnindxrow>
<nsn>
<fsc><xsl:value-of select="doc:federal_supply_classification"/></fsc>
<niin><xsl:value-of select="doc:national_item_identification_number"/></niin>
</nsn>
<xsl:for-each select="key('numkey', concat(doc:federal_supply_classification, doc:national_item_identification_number))">
<callout>
<xsl:attribute name="assocfig"><xsl:value-of select="concat('fig', doc:figure_number)"/></xsl:attribute>
<xsl:attribute name="label"><xsl:value-of select="doc:item_number"/></xsl:attribute>
</callout>
</xsl:for-each>
</nsnindxrow>
</xsl:template>
</xsl:stylesheet>
输出
（与之前的问题 XML 不同，由于此 XML 的一对 <federal_supply_classification> 和 <national_item_identification_number>，因此只呈现一个标注）.
<?xml version="1.0"?>
<nsnindxrows>
<nsnindxrow>
<nsn>
<fsc>1234</fsc>
<niin>000000000</niin>
</nsn>
<callout assocfig="fig1" label="1"/>
<callout assocfig="fig2" label="4"/>
<callout assocfig="fig3" label="2"/>
</nsnindxrow>
<nsnindxrow>
<nsn>
<fsc>1235</fsc>
<niin>111111111</niin>
</nsn>
<callout assocfig="fig1" label="1"/>
<callout assocfig="fig2" label="3"/>
</nsnindxrow>
<nsnindxrow>
<nsn>
<fsc>1236</fsc>
<niin>212121212</niin>
</nsn>
<callout assocfig="fig2" label="3"/>
</nsnindxrow>
</nsnindxrows>