DOMDocument读写XML文件

DOMDocument读写XML文件：

<?php
/**
* function：DOMDocument写XML文件
* author：JetWu
* date：2016.12.03
**/
$mysqli = mysqli_connect('localhost', 'root', '123456', 'wjt');
if(mysqli_connect_errno()) die('database connect fail:' . mysqli_connect_error());
 
$sql = 'select * from study order by starttime';
$res = mysqli_query($mysqli, $sql);
$study = array();
while($row = mysqli_fetch_array($res)) {
    $study[] = $row;
}
//XML标签配置
$xmlTag = array(
    'starttime',
    'endtime',
    'school'
);
 
$dom = new DOMDocument('1.0', 'utf8');
$dom->formatOutput = true;
$studentcareer = $dom->createElement('studentcareer');
$dom->appendChild($studentcareer);
foreach($study as $s) {
    $period = $dom->createElement('period');
    $studentcareer->appendChild($period);
    foreach($xmlTag as $x) {
        $element = $dom->createElement($x);
        $period->appendChild($element);
        $text = $dom->createTextNode($s[$x]);
        $element->appendChild($text);
    }
}
$dom->save('./write_dom.xml');

DOMDocument读XML文件：

<?php
/**
* function：DOMDocument读XML文件
* author：JetWu
* date：2016.12.03
**/
//XML标签配置
$xmlTag = array(
    'starttime',
    'endtime',
    'school'
);
$dom = new DOMDocument();
$dom->load('./write_dom.xml');
$periods = $dom->getElementsByTagName('period');
$study = array();
foreach($periods as $k => $p) {
    foreach($xmlTag as $x) {
        $node = $p->getElementsByTagName($x);
        $study[$k][$x] = $node->item(0)->nodeValue;
    }
}
echo '<pre>';
print_r($study);