php xml留言板 xml存储数据的简单例子

<?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;

        $k = 0;
        for($i = $start; $i < $end; $i++){
            $rowslist[$k]["nickname"] = $this->getelementsbytagname("nickname")->item($i)->nodevalue;
            $rowslist[$k]["content"] = $this->getelementsbytagname("content")->item($i)->nodevalue;
            $rowslist[$k]["timer"] = $this->getelementsbytagname("timer")->item($i)->nodevalue;
            $k++;
        }
        return $rowslist;
    }
    public static function splitpage($pageall,$page=1,$urled=null,$strpage = "page",$pageaverage = 10){
            $pageaverage -= 1;
            $page = intval($page >=1 ? $page : 1 );
            $page = $page > $pageall ? $pageall : $page;
            $startpage = $page - $pageaverage > 0 ? $page - ceil(($pageaverage / 2)):1;
            $startpage = ($page + ceil($pageaverage/2) > $pageall)?$pageall-$pageaverage:$startpage;

            $startpage = $startpage > 0 ? $startpage : 1;
            $stoppage = $startpage+$pageaverage >$pageall?$pageall:$startpage+$pageaverage;
            if(empty($urlfile)){ $urlfile=$_server["php_self"]; }
            if(!strrpos($urlfile,'?')) $urled .= '?';
            foreach($_get as $k => $v)
            {
                $urled = ($k<>$strpage) ? $urled.$k.'='.urlencode($v).'&' : $urled;
            }
            if ($page>1){
                $mess ="<a href="".$urled.$strpage."=1" href="".$urled.$strpage."=1">首页</a> ";
                $mess .="<a href="".$urled.$strpage."=".($page-1)."" href="".$urled.$strpage."=".($page-1)."">上一页 </a>";
            }else{
                $mess ="首页 ";
                $mess .="上一页 ";
            }
            if($page > 9){
                $startpage = $page - 9;
            }
            $stoppage = $startpage + 9 >= $pageall ? $pageall : $startpage + 9;
            for($i= $startpage; $i<= $stoppage ;$i++)
            {
                if($i<= $pageall && !($page==$i))
                    $mess .= "<a href="".$urled.$strpage."=".$i."" href="".$urled.$strpage."=".$i."">".$i."</a> ";
                else
                    $mess .= "".$i." ";
            }
            if ($page < $pageall){
                $mess .=" <a href="".$urled.$strpage."=".($page+1)."" href="".$urled.$strpage."=".($page+1)."">下一页</a>";
                $mess .=" <a href="".$urled.$strpage."=".$pageall."" href="".$urled.$strpage."=".$pageall."">尾页</a>";
            }else{
                $mess .=" 下一页";
                $mess .=" 尾页";
            }
        return $mess;
    }
}
?>

<?php
require("_class.xmldb.inc.php");
$xmldb = new xmldb("./my_xmldb.xml");
if(isset($_post["btnform1"])){
    $xmldb -> insert_message($_post["nickname"],$_post["content"]);
}
$pagesize        = 3;
$page            = !empty($_get['page']) ? intval($_get['page']) : 1;
$rowscount        = $xmldb -> get_node_length("rows");
$pagecount        = ceil($rowscount/$pagesize);
$start            = ($page-1)*$pagesize > $rowscount ? $rowscount : ($page-1)*$pagesize;
$rowslist = $xmldb -> get_message_list($start,$rowscount,$pagesize);
?>
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<title> new document </title>
    <style type='text/css'><!--
        #messagelist ul li{ float:left;list-style-type:none; }

--></style><style type='text/css' bogus="1">        #messagelist ul li{ float:left;list-style-type:none; }
    </style>
</head>
<body>
    <div id="messagelist">
    <?php
        if(!empty($rowslist))
        {
            foreach($rowslist as $key => $value)
            {
                echo "<ul><li>".$value["nickname"]." <span>(".date("y-m-d h:i",$value["timer"]).")</span></li>";
                echo "<li>".$value["content"]."</li></ul><br>";
            }
        }
    ?>
        <div><?=$xmldb -> splitpage($pagecount,$page,'','page',$pagesize)?></div>
    </div>
    <div>
        <form action="" method="post" name="form1">
            昵称:<input type="text" name="nickname"><br>
            内容:<textarea name="content">