Tips for reading and writing XML files with PHP_PHP tutorial

Commonly used lines are as follows:

header("content-type:text/html; charset=utf-8"); //Specify PHP to use UTF-8 encoding
$xml = simplexml_load_file("example.xml"); //Read xml file
$newxml = $xml->asXML(); //Standardize $xml
$fp = fopen("newxml.xml", "w"); //New xml file
fwrite($fp, $newxml); //Write -------xml file
fclose($fp);

PHP can easily generate and read XML files. PHP mainly completes XML reading and writing operations through DOMDocument, DOMElement and DOMNodeList. Below is a brief explanation of how to use these classes.

1. Generate XML file
For an XML file as follows.

[html] <?xml version="1.0" encoding="UTF-8"?>
<article>
<title>PHP Access MySql Database Basics</title>
<link>http://blog.csdn.net/morewindows/article/details/7102362</link>
</article>
<?xml version="1.0" encoding="UTF-8"?>
<article>
<title>PHP Access MySql Database Basics</title>
<link>http://blog.csdn.net/morewindows/article/details/7102362</link>
</article>
Let’s see how to generate it using PHP:

First create a new DOMDocument object and set the encoding format.

$dom = newDOMDocument('1.0', 'UTF-8');

$dom->formatOutput= true;

Create the <article> node and the <title> node

$rootelement =$dom->createElement("article");

$title =$dom->createElement("title", "PHP Access MySql Database - Elementary");

Then create a <link> node with text content

$link =$dom->createElement("link","http://blog.csdn.net/morewindows/article/details/7102362");

You can also generate a <link> node first and then add text content to it.

$link = $dom->createElement("link");

$linktext =$dom->createTextNode('http://blog.csdn.net/morewindows/article/details/7102362');

$link->appendChild($linktext);

Then add the <title> and <link> nodes to the <article> node

$rootelement->appendChild($title);

$rootelement->appendChild($link);

Finally, add the <article> node to the DOMDocument object,

$dom->appendChild($rootelement);

A complete XML is now generated. Then regenerate the entire XML,

echo $dom->saveXML() ;

saveXML() can also input only part of the XML text. For example, echo $dom->saveXML($link); will only output the <link> node: <link>http://blog.csdn. net/morewindows/article/details/7102362</link>

The following is a complete example of outputting data content to an XML file in PHP. This example will output a PHP array to an XML file.

[php] <?php
//Output the array to an XML file
// by MoreWindows( http://blog.csdn.net/MoreWindows )
$article_array = array(
"First article" => array(
"title"=>"PHP Access MySql Database Beginner",
"link"=>"http://blog.csdn.net/morewindows/article/details/7102362"
),
"Second article" => array(
"title"=>"PHP Access MySql Database Intermediate Smarty Technology",
"link"=>"http://blog.csdn.net/morewindows/article/details/7094642"
),
"Part 3" => array(
"title"=>"PHP Access MySql Database Advanced AJAX Technology",
"link"=>"http://blog.csdn.net/morewindows/article/details/7086524"
),
);
$dom = new DOMDocument('1.0', 'UTF-8');
$dom->formatOutput = true;
$rootelement = $dom->createElement("MoreWindows");
foreach ($article_array as $key=>$value)
{
$article = $dom->createElement("article", $key);
$title = $dom->createElement("title", $value['title']);
$link = $dom->createElement("link", $value['link']);
$article->appendChild($title);
$article->appendChild($link);
$rootelement->appendChild($article);

}
$dom->appendChild($rootelement);
$filename = "D:test.xml";
echo 'XML file size' . $dom->save($filename) . 'Bytes';
?>
<?php
//Output the array to an XML file
// by MoreWindows( http://blog.csdn.net/MoreWindows )
$article_array = array(
"First article" => array(
"title"=>"PHP Access MySql Database Beginner",
"link"=>"http://blog.csdn.net/morewindows/article/details/7102362"
),
"Second article" => array(
"title"=>"PHP Access MySql Database Intermediate Smarty Technology",
"link"=>"http://blog.csdn.net/morewindows/article/details/7094642"
),
"Part 3" => array(
"title"=>"PHP Access MySql Database Advanced AJAX Technology",
"link"=>"http://blog.csdn.net/morewindows/article/details/7086524"
),
);
$dom = new DOMDocument('1.0', 'UTF-8');
$dom->formatOutput = true;
$rootelement = $dom->createElement("MoreWindows");
foreach ($article_array as $key=>$value)
{
$article = $dom->createElement("article", $key);
$title = $dom->createElement("title", $value['title']);
$link = $dom->createElement("link", $value['link']);
$article->appendChild($title);
$article->appendChild($link);
$rootelement->appendChild($article);
}
$dom->appendChild($rootelement);
$filename = "D:test.xml";
echo 'XML file size' . $dom->save($filename) . 'Bytes';
?>
Running this PHP will generate the test.xml file on the D drive (Win7 + XAMPP + IE9.0 test passed)

2. Read XML file
Take reading the D:test.xml generated in the previous article as an example:

[php] <?php
//Read XML file
// by MoreWindows( http://blog.csdn.net/MoreWindows )
$filename = "D:test.xml";
$article_array = array();

$dom = new DOMDocument('1.0', 'UTF-8');
$dom->load($filename);

//Get the <article> node
$articles = $dom->getElementsByTagName("article");
echo '<article> Number of nodes' . $articles->length;
foreach ($articles as $article)
{
$id = $article->getElementsByTagName("id")->item(0)->nodeValue;
$title = $article->getElementsByTagName("title")->item(0)->nodeValue;
$link = $article->getElementsByTagName("link")->item(0)->nodeValue;
$article_array[$id] = array('title'=>$title, 'link'=>$link);
}

//Output results
echo "<pre>";
var_dump($article_array);
echo "</pre>";
?>
<?php
//Read XML file
// by MoreWindows( http://blog.csdn.net/MoreWindows )
$filename = "D:test.xml";
$article_array = array();

$dom = new DOMDocument('1.0', 'UTF-8');
$dom->load($filename);

//Get<article>node
$articles = $dom->getElementsByTagName("article");
echo '<article> Number of nodes' . $articles->length;
foreach ($articles as $article)
{
$id = $article->getElementsByTagName("id")->item(0)->nodeValue;
$title = $article->getElementsByTagName("title")->item(0)->nodeValue;
$link = $article->getElementsByTagName("link")->item(0)->nodeValue;
$article_array[$id] = array('title'=>$title, 'link'=>$link);
}

//Output results
echo "<pre>";
var_dump($article_array);
echo "</pre>";
?>

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