PHP分页原理是什么?如何实现

匿名网友 匿名网友 发布于: 2015-08-30 00:00:00
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<?php

Include(“conn.php”);

$pagesize=5;     //每一页显示5条信息

$url=$_SERVER[“REQUEST_URI”];         //取得当前的地址

$url=pars $url);

$url=$url[path];

 

$numq=mysql_query(“SELECT * FROM `test`”);    //通过sql语句查询数据库中共有多

$num = mysql_num_rows($numq);                少条语句赋给num

mysql_num_rows :是个

系统函数

 

if($_GET[page]){                                //计算公式 并且进行判断,没有

$pageval=$_GET[page];                           if($_GET[page])  一般会出错,

$page=($pageval-1)*$pagesize;

$page.=’,’;

}

 

if($num > $pagesize){                           //显示出来供用户使用

if($pageval<=1)$pageval=1;

echo “共 $num 条”.

” <a href=$url?page=”.($pageval-1).”>上一页</a> <a href=$url?page=”.($pageval+1).”>下一页</a>”;

}

 

$sql=”select*from `test` limt  $page $pagesize”;

$query=mysql_query($sql);

While($row=mysql_fetch_array($query)){

Echo”<hr> <b>”.$row[name].”|”.$row[sex];

}

?>

完整分页:

 

 

(1)    parse_url()解析URL函数

parse_url() 是讲URL解析成有固定键值的数组的函数

例: $ua=parse_url(“http://username:password@hostname/path?arg=value#anchor”);

print_r($ua);

结果:

Array

(

[scheme] => http

[host] => hostname

[user] => username

[pass] => password

[path] => /path

[query] => arg=value

[fragment] => anchor

)

 

<?php

 

function _PAGEFT($totle, $displaypg = 20, $url = ”) {

 

global $page, $firstcount, $pagenav, $_SERVER;

 

$GLOBALS[“displaypg”] = $displaypg;

 

if (!$page)

$page = 1;

if (!$url) {

$url = $_SERVER[“REQUEST_URI”];

}

 

//URL分析:

$parse_url = parse_url($url);

$url_query = $parse_url[“query”]; //单独取出URL的查询字串

if ($url_query) {

$url_query = ereg_replace(“(^|&)page=$page”, “”, $url_query);

$url = str_replace($parse_url[“query”], $url_query, $url);

if ($url_query)

$url .= “&page”;

else

$url .= “page”;

} else {

$url .= “?page”;

}

$lastpg = ceil($totle / $displaypg); //最后页,也是总页数

$page = min($lastpg, $page);

$prepg = $page -1; //上一页

$nextpg = ($page == $lastpg ? 0 : $page +1); //下一页

$firstcount = ($page -1) * $displaypg;

 

//开始分页导航条代码:

$pagenav = “显示第 <B>” . ($totle ? ($firstcount +1) : 0) . “</B>-<B>” . min($firstcount + $displaypg, $totle) . “</B> 条记录,共 $totle 条记录”;

 

//如果只有一页则跳出函数:

if ($lastpg <= 1)

return false;

 

$pagenav .= ” <a href=’$url=1′>首页</a> “;

if ($prepg)

$pagenav .= ” <a href=’$url=$prepg’>前页</a> “;

else

$pagenav .= ” 前页 “;

if ($nextpg)

$pagenav .= ” <a href=’$url=$nextpg’>后页</a> “;

else

$pagenav .= ” 后页 “;

$pagenav .= ” <a href=’$url=$lastpg’>尾页</a> “;

 

//下拉跳转列表,循环列出所有页码:

$pagenav .= “ 到第 <select name=’topage’ size=’1′ onchange=’window.location=”$url=”+this.value’>n”;

for ($i = 1; $i <= $lastpg; $i++) {

if ($i == $page)

$pagenav .= “<option value=’$i’ selected>$i</option>n”;

else

$pagenav .= “<option value=’$i’>$i</option>n”;

}

$pagenav .= “</select> 页,共 $lastpg 页”;

}

 

 

include(“conn.php”);

 

$result=mysql_query(“SELECT * FROM `test`”);

$total=mysql_num_rows($result);

//调用pageft(),每页显示10条信息(使用默认的20时,可以省略此参数),使用本页URL(默认,所以省略掉)。

_PAGEFT($total,5);

echo $pagenav;

 

$result=mysql_query(“SELECT * FROM `test` limit $firstcount,$displaypg “);

while($row=mysql_fetch_array($result)){

 

echo “<hr><b>”.$row[name].” | “.$row[sex];

 

}

 

 

?>

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