php缓存
- 什么是缓存？
a) 缓存就是在硬盘或者是内存当中临时存放数据的一块区域
- 为什么要使用缓存？
a) 降低数据库的访问压力
b) 减少对数据库的查询
c) 提高页面的响应速度
- 什么时候使用缓存？
a) 项目的访问量较大时
- 缓存的介质类型：
a) 硬盘（文件缓存）
- 数据缓存
- 序列化处理
a) Serialize 将数据进行序列化处理
b) Unserialize 将数据进行反序列化处理
- JSON格式
a) Json_encode 将数据转换成json格式的字符串
b) Json_decode 将数据转换成数组
- 注意，第二个参数为true，则为数组，否则为对象
- XML格式：
a) simpleXML_load_string()
- 数组格式：
a) var_export($data,true) 将数组打散成PHP语法格式的字符串
b) $data = include/require $cachefile; 直接将该文件return的内容返回
b) 内存（内存缓存）
- 缓存的形式：
a) 数据缓存
b) Html代码缓存
json格式
<?php header("content-type:text/html;charset=utf-8"); //1.定义缓存文件的名称 $cachefile = "./cache/2.php.json"; //2.定义缓存文件的生命周期 $cache_lifetime = 30; //判断缓存文件是否存在，并且是否过期，如果文件存在没有过期，读取缓存文件，否则查询数据库，生成缓存 if(file_exists($cachefile)&&time()-filemtime($cachefile)<=30){ //读取缓存文件 $data = file_get_contents($cachefile); //处理数据 $data = json_decode($data,true); }else{ echo "select data...."; //1.查询数据库 try{ $pdo = new PDO("mysql:host=localhost;dbname=psd1412","root","root",array(PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION)); $pdo->query("set names utf8"); $stmt = $pdo->prepare("select * from cms_user"); $stmt->execute(); $data = $stmt->fetchAll(PDO::FETCH_ASSOC); //将数据缓存到文件当中 //JSON //echo json_encode($data); file_put_contents($cachefile,json_encode($data)); }catch(PDOException $e){ echo $e->getMessage(); } } //2.遍历数据 echo "<table border='1' width='500'>"; echo "<tr>"; echo "<th>ID</th>"; echo "<th>username</th>"; echo "<th>rtime</th>"; echo "<th>rip</th>"; echo "</tr>"; foreach($data as $user){ echo "<tr>"; echo "<td>".$user['id']."</td>"; echo "<td>".$user['username']."</td>"; echo "<td>".date("Y-m-d H:i:s",$user['rtime'])."</td>"; echo "<td>".long2ip($user['rip'])."</td>"; echo "</tr>"; } echo "</table>";
//.json的数据格式
[{"id":"1","username":"admin","password":"202cb962ac59075b964b07152d234b70","rtime":"1426840429","rip":"2130706433"},{"id":"2","username":"ligousheng","password":"202cb962ac59075b964b07152d234b70","rtime":"1426840448","rip":"2130706433"},{"id":"3","username":"zhansgan","password":"202cb962ac59075b964b07152d234b70","rtime":"1426840457","rip":"2130706433"},{"id":"4","username":"lisi","password":"123","rtime":"123","rip":"123"},{"id":"5","username":"wangwu","password":"123","rtime":"123","rip":"123"},{"id":"6","username":"zhaoliu","password":"123","rtime":"123","rip":"123"},{"id":"7","username":"tianqi","password":"123","rtime":"123","rip":"123"},{"id":"8","username":"zhaoba","password":"123","rtime":"123","rip":"123"},{"id":"9","username":"lisi","password":"123","rtime":"123","rip":"123"},{"id":"10","username":"wangwu","password":"123","rtime":"123","rip":"123"},{"id":"11","username":"zhaoliu","password":"123","rtime":"123","rip":"123"},{"id":"12","username":"tianqi","password":"123","rtime":"123","rip":"123"},{"id":"13","username":"zhaoba","password":"123","rtime":"123","rip":"123"}]
序列化
<?php header("content-type:text/html;charset=utf-8"); //定义程序开始时间 $start = microtime(true); //1.定义缓存文件的名称 $cachefile = "./cache/1.php.cache"; //定义缓存的生命周期 $cache_lifetime = 30; //2.判断缓存文件是否存在 if(!file_exists($cachefile) || time()-filemtime($cachefile)>$cache_lifetime){ echo "select data...."; //数据库的查询 try{ $pdo = new PDO("mysql:host=localhost;dbname=psd1412","root","root",array(PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION)); $pdo->query("set names utf8"); $stmt = $pdo->prepare("select * from cms_user"); $stmt->execute(); //$data即为查询出的数据 $data = $stmt->fetchAll(PDO::FETCH_ASSOC); //将数据写入到缓存文件当中 //需要将数据提前处理一下 //序列化 /*class Person{ public $name='zhangsan'; } $p = new Person;*/ //echo serialize($data); file_put_contents($cachefile,serialize($data)); }catch(PDOException $e){ echo $e->getMessage(); } }else{ //读取缓存数据 $data = file_get_contents($cachefile); //处理序列化数据（反序列化） $data = unserialize($data); } //数据的遍历 echo "<table border='1' width='500'>"; echo "<tr><th>ID</th><th>用户名</th><th>注册时间</th><th>注册IP</th><th>操作</th></tr>"; foreach($data as $user){ echo "<tr>"; echo "<td>".$user['id']."</td>"; echo "<td>".$user['username']."</td>"; echo "<td>".date("Y-m-d H:i:s",$user['rtime'])."</td>"; echo "<td>".long2ip($user['rip'])."</td>"; echo "<td>编辑 删除</td>"; echo "</tr>"; } echo "</table>"; $end = microtime(true); echo "spend:".($end-$start);
序列化数据的格式：
a:13:{i:0;a:5:{s:2:"id";s:1:"1";s:8:"username";s:5:"admin";s:8:"password";s:32:"202cb962ac59075b964b07152d234b70";s:5:"rtime";s:10:"1426840429";s:3:"rip";s:10:"2130706433";}i:1;a:5:{s:2:"id";s:1:"2";s:8:"username";s:10:"ligousheng";s:8:"password";s:32:"202cb962ac59075b964b07152d234b70";s:5:"rtime";s:10:"1426840448";s:3:"rip";s:10:"2130706433";}i:2;a:5:{s:2:"id";s:1:"3";s:8:"username";s:8:"zhansgan";s:8:"password";s:32:"202cb962ac59075b964b07152d234b70";s:5:"rtime";s:10:"1426840457";s:3:"rip";s:10:"2130706433";}i:3;a:5:{s:2:"id";s:1:"4";s:8:"username";s:4:"lisi";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:4;a:5:{s:2:"id";s:1:"5";s:8:"username";s:6:"wangwu";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:5;a:5:{s:2:"id";s:1:"6";s:8:"username";s:7:"zhaoliu";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:6;a:5:{s:2:"id";s:1:"7";s:8:"username";s:6:"tianqi";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:7;a:5:{s:2:"id";s:1:"8";s:8:"username";s:6:"zhaoba";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:8;a:5:{s:2:"id";s:1:"9";s:8:"username";s:4:"lisi";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:9;a:5:{s:2:"id";s:2:"10";s:8:"username";s:6:"wangwu";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:10;a:5:{s:2:"id";s:2:"11";s:8:"username";s:7:"zhaoliu";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:11;a:5:{s:2:"id";s:2:"12";s:8:"username";s:6:"tianqi";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}i:12;a:5:{s:2:"id";s:2:"13";s:8:"username";s:6:"zhaoba";s:8:"password";s:3:"123";s:5:"rtime";s:3:"123";s:3:"rip";s:3:"123";}}
XML的形式
<?php header("content-type:text/html;charset=utf-8"); //1.定义缓存文件的名称 $cachefile = "./cache/3.php.xml"; //2.定义一个缓存文件的生命周期 $cache_lifetime = 30; //判断缓存文件是否存在，并且是否过期，如果存在并且没有过期，读取缓存文件，否则查询数据库，更新缓存文件 if(file_exists($cachefile)&&time()-filemtime($cachefile)<=$cache_lifetime){ //读取缓存文件 $data = file_get_contents($cachefile); //并且转换成二维数组 $obj = simplexml_load_string($data); $data = array(); foreach($obj->users->user as $user){ $data[] = array('id'=>strval($user->id),'username'=>strval($user->username),'password'=>strval($user->password),'rtime'=>strval($user->rtime),'rip'=>strval($user->rip)); } }else{ //查询数据库 try{ $pdo = new PDO("mysql:host=localhost;dbname=psd1412","root","root",array(PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION)); $pdo->exec("set names utf8"); $stmt = $pdo->prepare("select * from cms_user"); $stmt->execute(); $data = $stmt->fetchAll(PDO::FETCH_ASSOC); //拼装xml字符串，写入到xml文件当中 $xml = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>"; $xml .= "<root><users>"; foreach($data as $user){ $xml .= "<user>"; $xml .= "<id>".$user['id']."</id>"; $xml .= "<username>".$user['username']."</username>"; $xml .= "<rtime>".$user['rtime']."</rtime>"; $xml .= "<rip>".$user['rip']."</rip>"; $xml .= "</user>"; } $xml .= "</users></root>"; file_put_contents($cachefile,$xml); }catch(PDOException $e){ echo $e->getMessage(); } } //遍历数据 echo "<table border='1' width='500'>"; echo "<tr>"; echo "<th>ID</th>"; echo "<th>username</th>"; echo "<th>rtime</th>"; echo "<th>rip</th>"; echo "</tr>"; foreach($data as $user){ echo "<tr>"; echo "<td>".$user['id']."</td>"; echo "<td>".$user['username']."</td>"; echo "<td>".date("Y-m-d H:i:s",$user['rtime'])."</td>"; echo "<td>".long2ip($user['rip'])."</td>"; echo "</tr>"; } echo "</table>";
xml数据的格式
<?xml version="1.0" encoding="utf-8" ?><root><users><user><id>1</id><username>admin</username><rtime>1426840429</rtime><rip>2130706433</rip></user><user><id>2</id><username>ligousheng</username><rtime>1426840448</rtime><rip>2130706433</rip></user><user><id>3</id><username>zhansgan</username><rtime>1426840457</rtime><rip>2130706433</rip></user><user><id>4</id><username>lisi</username><rtime>123</rtime><rip>123</rip></user><user><id>5</id><username>wangwu</username><rtime>123</rtime><rip>123</rip></user><user><id>6</id><username>zhaoliu</username><rtime>123</rtime><rip>123</rip></user><user><id>7</id><username>tianqi</username><rtime>123</rtime><rip>123</rip></user><user><id>8</id><username>zhaoba</username><rtime>123</rtime><rip>123</rip></user><user><id>9</id><username>lisi</username><rtime>123</rtime><rip>123</rip></user><user><id>10</id><username>wangwu</username><rtime>123</rtime><rip>123</rip></user><user><id>11</id><username>zhaoliu</username><rtime>123</rtime><rip>123</rip></user><user><id>12</id><username>tianqi</username><rtime>123</rtime><rip>123</rip></user><user><id>13</id><username>zhaoba</username><rtime>123</rtime><rip>123</rip></user></users></root>
存入的是数组
<?php header("content-type:text/html;charset=utf-8"); //1.定义一个缓存文件名称 $cachefile = "./cache/4.data.php"; //2.声明缓存文件的生命周期 $cache_lifetime = 30; //判断缓存文件是否存在，并且是否过期，如果缓存文件存在，并且没有过期，直接读取缓存文件，否则查询数据库，更新缓存文件 if(file_exists($cachefile)&&time()-filemtime($cachefile)<=$cache_lifetime){ //读取缓存文件 $data = include $cachefile; }else{ echo "select data...."; //查询数据库 try{ $pdo = new PDO("mysql:host=localhost;dbname=psd1412","root","root",array(PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION)); $pdo->exec("set names utf8"); $stmt = $pdo->prepare("select * from cms_user"); $stmt->execute(); $data = $stmt->fetchAll(PDO::FETCH_ASSOC); //将数组写入到缓存文件当中 $str = "<?php\nreturn ".var_export($data,true).";"; file_put_contents($cachefile,$str); }catch(PDOException $e){ echo $e->getMessage(); } } //遍历数据 echo "<table border='1' width='500'>"; echo "<tr>"; echo "<th>ID</th>"; echo "<th>username</th>"; echo "<th>rtime</th>"; echo "<th>rip</th>"; echo "</tr>"; foreach($data as $user){ echo "<tr>"; echo "<td>".$user['id']."</td>"; echo "<td>".$user['username']."</td>"; echo "<td>".date("Y-m-d H:i:s",$user['rtime'])."</td>"; echo "<td>".long2ip($user['rip'])."</td>"; echo "</tr>"; } echo "</table>";
存入的是html格式
<?php header("content-type:text/html;charset=utf-8"); //1.缓存文件名称 $cachefile = "./cache/5.php.html"; //2.缓存的生命周期 $cache_lifetime = 30; //判断缓存文件是否存在，并且是否过期，如果缓存文件存在，并且没有过期，直接加载缓存文件即可，否则，读取数据库，并且更新数据 if(file_exists($cachefile)&&time()-filemtime($cachefile)<=$cache_lifetime){ include $cachefile; }else{ //查询数据库 try{ $pdo = new PDO("mysql:host=localhost;dbname=psd1412","root","root",array(PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION)); $pdo->exec("set names utf8"); $stmt = $pdo->prepare("select * from cms_user"); $stmt->execute(); $data = $stmt->fetchAll(PDO::FETCH_ASSOC); }catch(PDOException $e){ echo $e->getMessage(); } //遍历数据,拼接字符串，写入缓存文件 $html = "<table border='1' width='500'>"; $html .= "<tr>"; $html .= "<th>ID</th>"; $html .= "<th>username</th>"; $html .= "<th>rtime</th>"; $html .= "<th>rip</th>"; $html .= "</tr>"; foreach($data as $user){ $html .= "<tr>"; $html .= "<td>".$user['id']."</td>"; $html .= "<td>".$user['username']."</td>"; $html .= "<td>".date("Y-m-d H:i:s",$user['rtime'])."</td>"; $html .= "<td>".long2ip($user['rip'])."</td>"; $html .= "</tr>"; } $html .= "</table>"; file_put_contents($cachefile,$html); echo $html; }
