php DOMDocument 创建，加载，解析xml文档代码

$dom = new domdocument;
$dom->loadxml($xml_str);

echo $dom->savexml();
$dom->save("test.xml");

//domdocument 加载xml文档

$dom = new domdocument;

$dom->load('17-1.xml');
$root = $dom->documentelement;

$books = $doc->getelementsbytagname("book");
foreach($books as $book)
{
    $authors = $book->getelementsbytagname("author");
    $author = $authors->item(0)->nodevalue;
   
    $publishers = $book->getelementsbytagname("publisher");
    $publisher = $publishers->item(0)->nodevalue;
   
    $titles = $book->getelementsbytagname("title");
    $title = $titles->item(0)->nodevalue;
   
    $prices = $book->getelementsbytagname("price");
    $price = $prices->item(0)->nodevalue;
   
    echo "$title - $author - $publisher - $price";
    echo "<br/>";
    echo "<br/>";
}