如何使用xpath表达式从下面的数据中找出productID的最小和最大值

Question

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:nor="http://schemas.cordys.com/NorthwindMetadata">
   <soapenv:Header/>
   <soapenv:Body>
      <nor:UpdateOrder_x0020_Details reply="yes" commandUpdate="no" preserveSpace="no" batchUpdate="no">
         <nor:tuple>
            <nor:new>
               <nor:Order_x0020_Details qAccess="0" qConstraint="0" qInit="0" qValues="">
                  <nor:OrderID>11113</nor:OrderID>
                  <nor:ProductID>43</nor:ProductID>
                  <nor:UnitPrice>36.0000</nor:UnitPrice>
                  <nor:Quantity>25</nor:Quantity>
                  <nor:Discount>0</nor:Discount>
               </nor:Order_x0020_Details>
            </nor:new>
         </nor:tuple>
         <nor:tuple>
            <nor:new>
               <nor:Order_x0020_Details qAccess="0" qConstraint="0" qInit="0" qValues="">
                  <nor:OrderID>11113</nor:OrderID>
                  <nor:ProductID>30</nor:ProductID>
                  <nor:UnitPrice>99.000</nor:UnitPrice>
                  <nor:Quantity>10</nor:Quantity>
                  <nor:Discount>0</nor:Discount>
               </nor:Order_x0020_Details>
            </nor:new>
         </nor:tuple>
         <nor:tuple>
            <nor:new>
               <nor:Order_x0020_Details qAccess="0" qConstraint="0" qInit="0" qValues="">
                  <nor:OrderID>11113</nor:OrderID>
                  <nor:ProductID>40</nor:ProductID>
                  <nor:UnitPrice>88.0000</nor:UnitPrice>
                  <nor:Quantity>19</nor:Quantity>
                  <nor:Discount>0</nor:Discount>
               </nor:Order_x0020_Details>
            </nor:new>
         </nor:tuple>
      </nor:UpdateOrder_x0020_Details>
   </soapenv:Body>
</soapenv:Envelope>

Answer 1

I. XPath 2.0

使用此XPath 2.0表达式

   max(/*/*/*/*/*/*/nor:ProductID)

   min(/*/*/*/*/*/*/nor:ProductID)

使用此XPath 1.0表达式

/*/*/*/*/*/*/nor:ProductID
                   [not(. > following::nor:ProductID)
                  and
                    not(. > preceding::nor:ProductID)
                   ]

/*/*/*/*/*/*/nor:ProductID
                   [not(. < following::nor:ProductID)
                  and
                    not(. < preceding::nor:ProductID)
                   ]

这里的是两个解决方案的基于XSLT的验证。

XSLTI.XSLT1.0

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:nor="http://schemas.cordys.com/NorthwindMetadata">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="/">
  min:   <xsl:value-of select=
            "/*/*/*/*/*/*/nor:ProductID
                   [not(. > following::nor:ProductID)
                  and
                    not(. > preceding::nor:ProductID)
                   ]
     "/>
     <xsl:text>/ max: </xsl:text>
     <xsl:value-of select=
     "/*/*/*/*/*/*/nor:ProductID
                   [not(. &lt; following::nor:ProductID)
                  and
                    not(. &lt; preceding::nor:ProductID)
                   ]
     "/>
 </xsl:template>
</xsl:stylesheet>

在所提供的XML文档上应用此转换时为

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:nor="http://schemas.cordys.com/NorthwindMetadata">
    <soapenv:Header/>
    <soapenv:Body>
        <nor:UpdateOrder_x0020_Details reply="yes" commandUpdate="no" preserveSpace="no" batchUpdate="no">
            <nor:tuple>
                <nor:new>
                    <nor:Order_x0020_Details qAccess="0" qConstraint="0" qInit="0" qValues="">
                        <nor:OrderID>11113</nor:OrderID>
                        <nor:ProductID>43</nor:ProductID>
                        <nor:UnitPrice>36.0000</nor:UnitPrice>
                        <nor:Quantity>25</nor:Quantity>
                        <nor:Discount>0</nor:Discount>
                    </nor:Order_x0020_Details>
                </nor:new>
            </nor:tuple>
            <nor:tuple>
                <nor:new>
                    <nor:Order_x0020_Details qAccess="0" qConstraint="0" qInit="0" qValues="">
                        <nor:OrderID>11113</nor:OrderID>
                        <nor:ProductID>30</nor:ProductID>
                        <nor:UnitPrice>99.000</nor:UnitPrice>
                        <nor:Quantity>10</nor:Quantity>
                        <nor:Discount>0</nor:Discount>
                    </nor:Order_x0020_Details>
                </nor:new>
            </nor:tuple>
            <nor:tuple>
                <nor:new>
                    <nor:Order_x0020_Details qAccess="0" qConstraint="0" qInit="0" qValues="">
                        <nor:OrderID>11113</nor:OrderID>
                        <nor:ProductID>40</nor:ProductID>
                        <nor:UnitPrice>88.0000</nor:UnitPrice>
                        <nor:Quantity>19</nor:Quantity>
                        <nor:Discount>0</nor:Discount>
                    </nor:Order_x0020_Details>
                </nor:new>
            </nor:tuple>
        </nor:UpdateOrder_x0020_Details>
    </soapenv:Body>
</soapenv:Envelope>

生成所需的正确结果

  min:   30/ max: 43

<xsl:stylesheet version="2.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:nor="http://schemas.cordys.com/NorthwindMetadata">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="/">
    max: <xsl:sequence select=
     "max(/*/*/*/*/*/*/nor:ProductID)"/>
     <xsl:text>/ min: </xsl:text>
     <xsl:sequence select=
     "min(/*/*/*/*/*/*/nor:ProductID)"/>
 </xsl:template>
</xsl:stylesheet>

当将此转换应用于相同的XML文档(如上)时，同样会生成所需的正确答案

max: 43/ min: 30

最后说明：当在XPath表达式中使用前缀名称时，必须使用所使用的XPath引擎的来注册名称空间和前缀到它的绑定。

Answer 2

使用此XPath查找具有最大nor:ProductID的nor:tuple

//nor:tuple[
    not(following-sibling::nor:tuple/nor:new//nor:ProductID > nor:new//nor:ProductID 
        or 
        preceding-sibling::nor:tuple/nor:new//nor:ProductID > nor:new//nor:ProductID)
]

要查找最大值(在您的示例43中)：

//nor:tuple[
    not(following-sibling::nor:tuple/nor:new//nor:ProductID > nor:new//nor:ProductID 
        or 
        preceding-sibling::nor:tuple/nor:new//nor:ProductID > nor:new//nor:ProductID)
]/nor:new//nor:ProductID

要查找最小值，请用<替换>。