Example code for reading and writing XML DOM with PHP_PHP tutorial

// Read XML using DOM
$doc = new DOMDocument();
$doc->load(‘test.xml’);

$books = $doc->getElementsByTagName(“book”);

foreach( $books as $book ){
$authors = $book->getElementsByTagName(“author”);
$author = $authors->item(0)->nodeValue; // The nodeValue attribute can set or return the value of a node according to the node type.

$publishers = $book->getElementsByTagName(“publisher”);
$publisher = $publishers->item(0)->nodeValue;

$titles = $book->getElementsByTagName( ”title” );
$title = $titles->item(0)->nodeValue;

echo ”Title: $title
Author: $author
Publisher: $publisher

/*
The script first creates a new DOMdocument object, and uses the load method to load the book XML into this object. Afterwards, the script uses the getElementsByName method to get a list of all elements under the specified name.
In the loop of the book node, the script uses the getElementsByName method to obtain the nodeValue of the author, publisher and title tags. nodeValue is the text in the node. The script then displays these values.
*/

// Read XML with SAX parser

$g_books = array();
$g_elem = null;

function startElement( $parser, $name, $attrs ){
global $g_books, $g_elem;
if ( $name == 'BOOK' ) $g_books []= array();
$g_elem = $name;
}

function endElement( $parser, $name ){
global $g_elem;
$g_elem = null;
}

function textData( $parser, $text ){
global $g_books, $g_elem;
if ( $g_elem == 'AUTHOR' || $g_elem == 'PUBLISHER' || $g_elem == 'TITLE' ){
$g_books[ count( $g_books ) - 1 ][ $g_elem ] = $text;
}
}

$parser = xml_parser_create();

xml_set_element_handler( $parser, ”startElement”, ”endElement” );
xml_set_character_data_handler( $parser, ”textData” );

$f = fopen( ’test.xml’, ’r’ );

while( $data = fread( $f, 4096 ) ){
xml_parse( $parser, $data );
}

xml_parser_free( $parser );

foreach( $g_books as $book ){
echo $book['TITLE']." - ".$book['AUTHOR']." - ";
echo $book['PUBLISHER' ].”n”;
}

/*

The script first sets up the g_books array, which holds all the books and book information in memory, and the g_elem variable holds the name of the tag the script is currently processing. The script then defines the callback function. In this example, the callback functions are startElement, endElement, and textData. When opening and closing the mark, call the startElement and endElement functions respectively. Call textData on the text between the opening and closing tags.

In this example, the startElement tag looks for the book tag to start a new element in the book array. The textData function then looks at the current element to see if it is a publisher, title, or author tag. If so, the function puts the current text into the current book.

To allow parsing to continue, the script creates a parser using the xml_parser_create function. Then, set the callback handle. Afterwards, the script reads the file and sends chunks of the file to the parser. After the file is read, the xml_parser_free function removes the parser. The end of the script prints the contents of the g_books array.

*/

// Parse XML with regular expressions

$xml = ”";
$f = fopen( 'test.xml', 'r' );
while( $data = fread( $f, 4096 ) ) { $xml .= $ data; }
fclose( $f );

preg_match_all( ”/(.*?)/s”, $xml, $bookblocks );

foreach( $bookblocks[1] as $block ){
preg_match_all( ”/(.*?)/”, $block, $author );
preg_match_all ( ”//”, $block, $title );
preg_match_all( ”/(.*?)/” , $block, $publisher );
echo( $title[1][0].” - ”.$author[1][0].” - ”. $publisher[1][0].”n ” );
}

/*
I never recommend using regular expressions to read XML, but sometimes it is the most compatible way because the regular expression functions are always available. Do not use regular expressions to read XML directly from the user because you have no control over the format or structure of such XML. You should always use a DOM library or a SAX parser to read XML from the user.
*/

//Write XML using DOM

$books = array();
$books [] = array(
’title’ => ’PHP Hacks’,
’author’ => ’Jack Herrington’,
’publisher’ => ”O’Reilly”
);
$books [] = array(
’title’ => ’Podcasting Hacks’,
’author’ => ’Jack Herrington’,
’publisher’ => ”O’Reilly”
);

$doc = new DOMDocument();
$doc->formatOutput = true;

$r = $doc->createElement( ”books” );
$doc->appendChild( $r );

foreach( $books as $book ){
$b = $doc->createElement( ”book” );

$author = $doc->createElement( ”author” );
$author->appendChild( $doc->createTextNode( $book['author'] ) );

$b->appendChild( $author );

$title = $doc->createElement( ”title” );
$title->appendChild( $doc->createTextNode( $book['title'] ) );

$b->appendChild( $title );

$publisher = $doc->createElement( ”publisher” );
$publisher->appendChild( $doc->createTextNode( $book['publisher'] ) );

$b->appendChild( $publisher );
$r->appendChild( $b );
}

//echo $doc->saveXML();

/*
在脚本的顶部，用一些示例图书装入了 books 数组。这个数据可以来自用户也可以来自数据库。
示例图书装入之后，脚本创建一个 new DOMDocument，并把根节点 books 添加到它。然后脚本为每本书 的 author、title 和 publisher 创建节点，并为每个节点添加文本节点。每个 book 节点的最后一步是重新把它添加到根节 点 books。
使用 DOM 的真正价值在于它创建的 XML 总是格式正确的。但是如果不能用 DOM 创建 XML 时该怎么办？

Xml代码

PHP 编写xml

$books = array();
$books [] = array(
’title’ => ’PHP Hacks’,
’author’ => ’Jack Herrington’,
’publisher’ => ”O’Reilly”
);
$books [] = array(
’title’ => ’Podcasting Hacks’,
’author’ => ’Jack Herrington’,
’publisher’ => ”O’Reilly”
);
?>

foreach( $books as $book )
{
?>







}
?>

实例中用到的 test.xml 如下：

Jack Herrington

O’Reilly

Jack Herrington

O’Reilly