$thread = DB::fetch_all("SELECT * FROM ".DB::table('forum_thread')." ORDER BY tid DESC");

// 创建一个DOMDocument对象
$dom = new DOMDocument("1.0","utf-8");
header("Content-Type: text/xml");
// 创建根节点
$root = $dom->createElement("urlset");
$dom->appendChild($root);
foreach($thread as $value){
    // 建立根下子节点track
    $track = $dom->createElement("url");
    $root->appendChild($track);
    // 建立track节点下元素
    $loc = $dom->createElement("loc");
        $track->appendChild($loc);
    $priority = $dom->createElement("priority");
        $track->appendChild($priority);
    $lastmod = $dom->createElement("lastmod");
        $track->appendChild($lastmod);
    $changefreq = $dom->createElement("changefreq");
        $track->appendChild($changefreq);

    // 赋值
    $text = $dom->createTextNode('http://localhost/thread-'.$value[tid].'-1-1.html');
    $loc->appendChild($text);
    $date = date("Y-m-d",time());
    $text = $dom->createTextNode($date);
    $lastmod->appendChild($text);
    $text = $dom->createTextNode(daily);
    $changefreq->appendChild($text);
    $text = $dom->createTextNode(0.8);
    $priority->appendChild($text);
}
//生成xml文件
$dom->save("sitemap.xml");exit;