Question

我正在尝试使用PHP从XML中读取一些值。但问题是我想用变量名读取它们，如下所示 -

    <?php

    $xml = '<RESPONSE type=\"WEBRESPONSE\">
       <NAME>ALBERT</NAME>
       <HTTPSTATUS>200</HTTPSTATUS>
       <VALUES>
          <VALUE1>ABCD</VALUE1>
          <VALUE2>DEFG</VALUE2>
          <VALUE3>HIJK</VALUE3>
       </VALUES>
    </RESPONSE>';

    $responseMappings = array(
        "VALUE1","VALUE2","VALUE3"
        );

    $xmlResponse = @simplexml_load_string ( $xml );
    $values = $xmlResponse->VALUES;
    foreach($responseMappings as $responseMapping){
            //Refer using variable name below? How to?
        echo "Value : ".($values->${responseMapping});
    }
?>

我想使用$responseMapping中的变量名$values来引用或选择值。我不知道如何做到这一点。

非常感谢任何帮助。

Answer 1

你很接近，但有两件事：

首先，XML无效（看起来就像是一些拼写错误，因为你没有检查过你的示例代码）。在您禁止这些错误时，您需要启用错误记录并跟踪错误日志。解决这些问题。
然后修复如何进行变量属性访问，（a）正确的代码是：
```
echo "Value : " . $values->{$responseMapping};
```

示例性输出：

Value : ABCD
Value : DEFG
Value : HIJK

查看完整的工作代码示例（run it as an online demo）：

<?php
/**
 * @link http://stackoverflow.com/a/24116883/367456
 * @link https://eval.in/160030
 */

$xml = '
<RESPONSE type="WEBRESPONSE">
    <NAME>ALBERT</NAME>
    <HTTPSTATUS>200</HTTPSTATUS>
    <VALUES>
      <VALUE1>ABCD</VALUE1>
      <VALUE2>DEFG</VALUE2>
      <VALUE3>HIJK</VALUE3>
    </VALUES>
</RESPONSE>';

$responseMappings = array(
    "VALUE1", "VALUE2", "VALUE3"
);

$xmlResponse = simplexml_load_string($xml);
if (!$xmlResponse) {
    throw new RuntimeException('Failed to open XML');
}

$values      = $xmlResponse->VALUES;
foreach ($responseMappings as $responseMapping) {
    //Refer using variable name below? How to?
    echo "Value : " . $values->{$responseMapping}, "\n";
}

但如果你允许我一些额外的想法：

认为不同：所有这三个<VALUE?>元素都有共同之处：它们是<VALUES>的子元素。这样做你不需要保留元素名称的数组。

该场景的示例性输出：

Value "VALUE1": ABCD
Value "VALUE2": DEFG
Value "VALUE3": HIJK

这是另一个工作代码示例（run it as an online demo）：

<?php
/**
 * @link http://stackoverflow.com/a/24116883/367456
 * @link https://eval.in/160032
 */

$xml = '
<RESPONSE type="WEBRESPONSE">
    <NAME>ALBERT</NAME>
    <HTTPSTATUS>200</HTTPSTATUS>
    <VALUES>
      <VALUE1>ABCD</VALUE1>
      <VALUE2>DEFG</VALUE2>
      <VALUE3>HIJK</VALUE3>
    </VALUES>
</RESPONSE>';


$xmlResponse = simplexml_load_string($xml);
if (!$xmlResponse) {
    throw new RuntimeException('Failed to open XML');
}

/** @var SimpleXMLElement $values */
$values = $xmlResponse->VALUES;
foreach ($values->children() as $name => $value) {
    //Refer using variable name below? How to?
    printf("Value \"%s\": %s\n", $name, $value);
}

Answer 2

您可以尝试以下内容：

$dom = new DOMDocument;
$dom->loadXML($xml);
$books = $dom->getElementsByTagName('VALUE1');
foreach ($books as $book) {
    echo $book->nodeValue, PHP_EOL;
}

了解更多信息：http://www.php.net/manual/en/domdocument.getelementsbytagname.php

Answer 3

替代方案你可以做这样的事情。考虑这个例子：

$xml = '<RESPONSE type="WEBRESPONSE">
   <NAME>ALBERT</NAME>
   <HTTPSTATUS>200</HTTPSTATUS>
   <VALUES>
      <VALUE1>ABCD</VALUE1>
      <VALUE2>DEFG</VALUE2>
      <VALUE3>HIJK</VALUE3>
   </VALUES>
</RESPONSE>';

$responseMappings = array("VALUE1","VALUE2","VALUE3");
$data = array();
$xmlResponse = simplexml_load_string($xml);
$xmlResponse = json_decode(json_encode($xmlResponse), true);
foreach($responseMappings as $key => $value) {
    $data[$value] = $xmlResponse['VALUES'][$value];
}

echo '<pre>';
print_r($data);
echo '</pre>';

示例输出：

Array
(
    [VALUE1] => ABCD
    [VALUE2] => DEFG
    [VALUE3] => HIJK
)

Answer 4

尝试使用foreach()和array_merge()

$xml = '<RESPONSE type="WEBRESPONSE">
       <NAME>ALBERT</NAME>
       <HTTPSTATUS>200</HTTPSTATUS>
       <VALUES>
          <VALUE1>ABCD</VALUE1>
          <VALUE2>DEFG</VALUE2>
          <VALUE3>HIJK</VALUE3>
       </VALUES>
    </RESPONSE>';
$xmlResponse = simplexml_load_string($xml);
$values = $xmlResponse->VALUES;
$responseMapping = array();
foreach($values as $k => $v){
    $responseMappings[$k] = $v;
}
$responseMapping = array_merge($responseMapping,(array)$responseMappings['VALUES']);
print_r($responseMapping); //Array([VALUE1] => ABCD [VALUE2] => DEFG [VALUE3] => HIJK)

使用变量名读取xml值

4 个答案: