php xml留言板 xml存储数据的简单例子

类文件 : _class.xmldb.inc.php

<?php
class xmldb extends DOMDocument{
    var $xmldb;
    public function __construct($xmldbname){
        $this->xmldb=$xmldbname;
        if(!file_exists($this->xmldb)){
            $initxmldb = "<?xml version="1.0" encoding="utf-8"?><Message></Message>";
            $this->loadXML($initxmldb);
            $this->save($this->xmldb);
        }else{
            $this->load($this->xmldb);
        }

    }
    public function insert_message($nickname,$message){

        $messagedom = $this->getElementsByTagName("Message");
        $subnode = $this->createElement("Rows");
        $nicknamenode = $this->createElement("Nickname");
        $nicknamenode -> appendChild($this->createTextNode($nickname));
        $subnode -> appendChild($nicknamenode);
        $contentnode = $this->createElement("Content");
        $contentnode -> appendChild($this->createTextNode($message));
        $subnode -> appendChild($contentnode);
        $timernode = $this->createElement("Timer");
        $timernode -> appendChild($this->createTextNode(time()));
        $subnode -> appendChild($timernode);
        $messagedom->item(0)->appendChild($subnode);
        $this->saveXML();
        $this->save($this->xmldb);
    }
    function get_node_length($nodename){

        $odom = $this->getElementsByTagName($nodename);
        return $odom->length;
    }
    public function get_message_list($start,$rowscount,$pagesize){
        $end = $rowscount > $pagesize ? $start+$pagesize : $rowscount;

        $k = 0;