Question

我从XML中提取数据，而某些标签以这种方式在CDATA中包含数据

<description><![CDATA[Changes (as compared to 8.17) include:
Features:
    * Added a &#8216;Schema Optimizer&#8217; feature. Based on &#8220;procedure analyse()&#8221; it will propose alterations to data types for a table based on analysis on what data are stored in the table. The feature is available from INFO tab/HTML mode.  Refer to documentation for details.
    * A table can now be added [...]]]>
</description>

我已经在使用preq_match从描述标记中提取数据。那么如何从CDATA中提取数据？

Answer 1

无论使用哪种语言，都不要使用正则表达式来解析XML - 你几乎肯定会弄错它。使用XML parser。

Answer 2

如果您需要提取一组复杂的数据，则应使用simple_xml和xpath。

<?php
$string = <<<XML
<?xml version='1.0'?> 
<document>
 <title>Forty What?</title>
 <from>Joe</from>
 <to>Jane</to>
 <body>
  I know that's the answer -- but what's the question?
 </body>
</document>
XML;

$xml = simplexml_load_string($string);

var_dump($xml);
?>

会提供如下输出：

SimpleXMLElement Object
(
  [title] => Forty What?
  [from] => Joe
  [to] => Jane
  [body] =>
   I know that's the answer -- but what's the question?
)

所以在你的情况下，你只需要在文档中导航，然后在表达式中更容易，不是吗？

Answer 3

@Pavel Minaev是正确的保留正则表达式的选项作为最后的手段，并且对于xml总是使用Xml解析器，您现在可以在几乎所有语言中找到xml解析器。例如我通常使用DOMDocument在php中解析或创建xml。它非常简单易懂，特别适合像我这样偶尔使用php的人。

例如，您希望从以下xml中提取CDATA

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE message SYSTEM "https://www.abcd.com/dtds/AbcdefMessageXmlApi.dtd">
<message id="9002">
  <report>
    <![CDATA[id:50121515075540159 sub:001 text text text text text]]>
  </report>
  <number>353874181931</number>
</message>

使用以下代码提取CDATA

$doc = new DOMDocument();
$doc->preserveWhiteSpace = false;

if (TRUE != $doc->loadXML($xml_response)) {

    // log error and / or throw expection or whatever
}

$response_element = $doc->documentElement;

if($response_element->tagName ==  "message"){

    $report_node = $response_element->getElementsByTagName("report");

    if($report_node != null && $report_node->length == 1) {

        $narrative = $report_node->item(0)->textContent;

        $log->debug("CDATA: $narrative");

    } else {

        $log->error("unable to find report tag or multiple report tag found in response xml");
    }

} else {

    $log->error("unexpected root tag (" . $response_element->tagName .") in response xml");
}

执行此$narrative变量后应该包含所有文本，不要担心它不会包含丑陋的标记部分CDATA。

快乐编码：）

如何从CDATA中提取数据

3 个答案: