我无法使用 Xpath 提取节点文本

Question

我有一个像这样的 XML 文件 (test.xml):

<?xml version="1.0" encoding="ISO-8859-1"?>
<s2xResponse>
  <s2xData>
    <Name>This is the name</Name>
    <InfocomData>
      <DateOfUpdate day="07" month="02" year="2018">20180207</DateOfUpdate>
      <CompanyName>MY COMPANY</CompanyName>
      <TaxCode FlagCheck="0">XXXYYYWWWZZZ</TaxCode>
    </InfocomData>
    <AssessmentSummary>
      <Rating Code="2">Rating Description for Code 2</Rating>
    </AssessmentSummary>
    <AssessmentData>
      <SectorialDistribution>
        <CompaniesNumber>11650</CompaniesNumber>
        <ScoreDistribution />
        <CervedScoreDistribution>
          <DistributionData>
            <Rating Code="1">SICUREZZA</Rating>
            <Percentage>1.91</Percentage>
          </DistributionData>
          <DistributionData>
            <Rating Code="2">SOLVIBILITA' ELEVATA</Rating>
            <Percentage>35.56</Percentage>
          </DistributionData>
        </CervedScoreDistribution>
      </SectorialDistribution>
    </AssessmentData>
  </s2xData>
</s2xResponse>

我正在尝试使用 XmlExtractor 通过 U-SQL 脚本获取 "Name" 节点文本 ("This is the name")。以下是我使用的代码：

USE TestXML; // It contains the registered assembly

REFERENCE ASSEMBLY [Microsoft.Analytics.Samples.Formats];

@xml = EXTRACT xml_text string
       FROM "textxpath/test.xml"
       USING Extractors.Text(rowDelimiter: "^", quoting: false);

@xml_cleaned =
    SELECT
        xml_text.Replace("\r\n", "").Replace("\t", "    ") AS xml_text
    FROM @xml;

@values =
    SELECT Microsoft.Analytics.Samples.Formats.Xml.XPath.Evaluate(xml_text, "s2xResponse/s2xData/Name")[1] AS value
    FROM @xml_cleaned;


OUTPUT @values TO @"outputs/test_xpath.txt" USING Outputters.Text(quoting: false);

但是我遇到了这个运行时错误：

Execution failed with error '1_SV1_Extract Error : '{"diagnosticCode":195887116,"severity":"Error","component":"RUNTIME","source":"User","errorId":"E_RUNTIME_USER_EXPRESSIONEVALUATION","message":"Error while evaluating expression Microsoft.Analytics.Samples.Formats.Xml.XPath.Evaluate(xml_text.Replace(\"\r\n\", \"\").Replace(\"\t\", \" \"), \"s2xResponse/s2xData/Name\")[1]","description":"Inner exception from user expression: Index was out of range. Must be non-negative and less than the size of the collection.

即使我对评估结果 ([0]) 使用零索引，我也会遇到同样的错误。

我的查询有什么问题？

Answer 1

这里的问题是您将下标 [1] 应用于 XPath.Evaluate 的结果，我相信这将返回 Name 节点。但是，您是在代码中而不是在 XPath 中应用 [1] 下标，因此下标可能是从零开始的，而不是像在 XPath 中那样从 1 开始的，因此出现 Index out of range 错误。

这是一个解决方案 - 只需在 Xpath 中应用下标运算符（它仍然基于 1），然后 select text() 那里

 .Evaluate("s2xResponse/s2xData/Name[1]/text()")

Answer 2

您想使用 Evaluate 方法有什么特别的原因吗？我让他使用 XmlDomExtractor 工作，这将允许您从 xml 中提取多个值，例如

REFERENCE ASSEMBLY [Microsoft.Analytics.Samples.Formats];

DECLARE @inputFile string = "/input/input100.xml";

@input =
    EXTRACT Name string
    FROM @inputFile
    USING new Microsoft.Analytics.Samples.Formats.Xml.XmlDomExtractor(rowPath : "/s2xResponse",
          columnPaths : new SQL.MAP<string, string>{
          { "s2xData/Name", "Name" },
          }
          );


@output =
    SELECT *
    FROM @input;

我无法使用 Xpath 提取节点文本

I can't extract the node text with a Xpath

xpath

azure-data-lake

u-sql