When working with XML-based applications, developers often need to create XML-encoded data structures. For example, XML status templates in the Web based on user input, server request XML statements, and client responses based on runtime parameters.
Although the construction of XML data structure is time-consuming, if you use the mature PHP DOM application interface, everything will become simple and clear. In this article, Dane PHP training teacher will introduce you to the main functions of the PHP DOM application interface and demonstrate how to generate a correct complete XML file and save it to disk.
Create a document type declaration
Generally speaking, XML declarations are placed at the top of the document. Declaration in PHP is very simple: just instantiate an object of the DOM document class and give it a version number. View Program Listing A:
Program List A
The code is as follows | |
代码如下 | |
// create doctype $dom = new DOMDocument("1.0"); // display document in browser as plain text // display document in browser as plain text // for readability purposes header("Content-Type: text/plain"); // save and display tree echo $dom->saveXML(); ?> |
$dom = new DOMDocument("1.0");
// display document in browser as plain text
// display document in browser as plain text
// for readability purposes
header("Content-Type: text/plain");
// save and display tree
echo $dom->saveXML();
?>
If you view the output in a browser, you can see the following code:
代码如下 | |
// create doctype |
The code is as follows | |
// create doctype<🎜> $dom = new DOMDocument("1.0");<🎜> // display document in browser as plain text<🎜> // for readability purposes<🎜> header("Content-Type: text/plain");<🎜> // create root element<🎜> $root = $dom->createElement("toppings"); $dom->appendChild($root); // create child element $item = $dom->createElement("item"); $root->appendChild($item); // create text node $text = $dom->createTextNode("pepperoniwww.111cn.net"); $item->appendChild($text); // save and display tree echo $dom->saveXML(); ?> |
Here, I first create a root element named
If you want to add another topping, just create another
Program List C
The code is as follows | |||||
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Add attributes
Earlier we continued to share with you the content of the simple example code (1) for generating XML by PHP. Next, Beijing PHP training will continue to share the content of the simple example code (2) for generating XML by PHP.
By using attributes, you can also add appropriate information to elements. For the PHP DOM API, adding an attribute requires two steps: first create a node with the attribute name using the createAttribute() method of the DOM document object, and then add the document node to the attribute node with the attribute value. See Listing D for details.
Program List D
The code is as follows | |
代码如下 | |
// create doctype $dom = new DOMDocument("1.0"); // display document in browser as plain text // for readability purposes header("Content-Type: text/plain"); // create root element $root = $dom->createElement("toppings"); $dom->appendChild($root); // create child element $item = $dom->createElement("item"); $root->appendChild($item); // create text node $text = $dom->createTextNode("pepperoni"); $item->appendChild($text); // create attribute node $price = $dom->createAttribute("price"); $item->appendChild($price); // create attribute value node $priceValue = $dom->createTextNode("4"); $price->appendChild($priceValue); // save and display tree echo $dom->saveXML(); ?> 输出如下所示: |
Add CDATA module and process wizard
Although CDATA modules and process wizards are not often used, the PHP API can also support CDATA and process wizards well by calling the createCDATASection() and createProcessingInstruction() methods of the DOM document object, see Program Listing E.
Program List E
The code is as follows | |
代码如下 | |
// create doctype // create doctype $dom = new DOMDocument("1.0"); // display document in browser as plain text // for readability purposes header("Content-Type: text/plain"); // create root element $root = $dom->createElement("toppings"); $dom->appendChild($root); // create child element $item = $dom->createElement("item"); $root->appendChild($item); // create text node $text = $dom->createTextNode("pepperoni"); $item->appendChild($text); // create attribute node $price = $dom->createAttribute("price"); $item->appendChild($price); // create attribute value node $priceValue = $dom->createTextNode("4"); $price->appendChild($priceValue); // create CDATA section $cdata = $dom->createCDATASection(" Customer requests that pizza be sliced into 16 square pieces "); $root->appendChild($cdata); // create PI $pi = $dom->createProcessingInstruction("pizza", "bake()"); $root->appendChild($pi); // save and display tree echo $dom->saveXML(); ?> 输出如下所示: Customer requests that pizza be sliced into 16 square pieces ]]> |
Save results
Once you have achieved your goal, you can save the results in a file or store them in a PHP variable. The results can be saved in a file by calling the save() method with a file name, or in a PHP variable by calling the saveXML() method. Please refer to the following example (Program List F):
Program List F
代码如下 | |
// create doctype $dom = new DOMDocument("1.0"); // create root element $root = $dom->createElement("toppings"); $dom->appendChild($root); $dom->formatOutput=true; // create child element $item = $dom->createElement("item"); $root->appendChild($item); // create text node $text = $dom->createTextNode("pepperoni"); $item->appendChild($text); // create attribute node $price = $dom->createAttribute("price"); $item->appendChild($price); // create attribute value node $priceValue = $dom->createTextNode("4"); $price->appendChild($priceValue); // create CDATA section $cdata = $dom->createCDATASection(" Customer requests that pizza be sliced into 16 square pieces "); $root->appendChild($cdata); // create PI $pi = $dom->createProcessingInstruction("pizza", "bake()"); $root->appendChild($pi); // save tree to file $dom->save("order.xml"); // save tree to string $order = $dom->save("order.xml"); ?> 下面是实际的例子,大家可以测试下。 xml.php(生成xml) $conn = mysql_connect('localhost', 'root', '123456') or die('Could not connect: ' . mysql_error()); mysql_select_db('vdigital', $conn) or die ('Can't use database : ' . mysql_error()); $str = "SELECT id,username FROM `admin` GROUP BY `id` ORDER BY `id` ASC"; $result = mysql_query($str) or die("Invalid query: " . mysql_error()); if($result) { $xmlDoc = new DOMDocument(); if(!file_exists("01.xml")){ $xmlstr = " $xmlDoc->loadXML($xmlstr); $xmlDoc->save("01.xml"); } else { $xmlDoc->load("01.xml");} $Root = $xmlDoc->documentElement; while ($arr = mysql_fetch_array($result)){ $node1 = $xmlDoc->createElement("id"); $text = $xmlDoc->createTextNode(iconv("GB2312","UTF-8",$arr["id"])); $node1->appendChild($text); $node2 = $xmlDoc->createElement("name"); $text2 = $xmlDoc->createTextNode(iconv("GB2312","UTF-8",$arr["username"])); $node2->appendChild($text2); $Root->appendChild($node1); $Root->appendChild($node2); $xmlDoc->save("01.xml"); } } mysql_close($conn); ?> test.php(应用测试) $xmlDoc = new DOMDocument(); $xmlDoc->load("http://localhost/xml/xml.php"); $x=$xmlDoc->getElementsByTagName('name'); for ($i=0; $i<=$x->length-1; $i++) { if(strpos($x->item($i)->nodeValue,"fang")!==false) { echo $x->item($i)->parentNode->childNodes->item(1)->nodeValue; } } ?> |