Memcached实战之简单留言板

落日映苍穹つ 2022-07-16 08:30 194阅读 0赞

# MyPdo.php #

<?php
    
    class MyPdo{
         
    
        private $pdo;
    
        function __construct()
        {
         
            $this->pdo = $this->getPdo();
        }
    
         /**
         * CreatePDO
         *
         * @return PDO
         */
        public function getPdo()
        {
         
            $dbms='mysql';
            $dbName='testdb';
            $user='root';
            $pwd='diligentyang';
            $host='localhost';
            $dsn="$dbms:host=$host;dbname=$dbName";
            try{
                $pdo=new PDO($dsn,$user,$pwd);
            }catch(Exception $e){
                echo $e->getMessage().'<br>';
                exit();
            }
            $pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
            $pdo->exec("set names utf8");
            return $pdo;
        }
    
         /**
         * Execute SQL
         *
         * @param string $sql  Sql
         * @param string $mode Mode
         *
         * @return mixed
         */
        function query($sql = "", $mode = "array")
        {
         
            $sql = trim($sql);
            if ($sql == "") {
                $this->showErrors("the mothe query neet at least one param!");
            }
            $query = $this->pdo->query($sql);
    
            if (!$query) {
                $this->showErrors("the sql string is false");
            }
            if (strpos(strtolower($sql), "select") ===false) {
                return $query;
            }
    
            switch ($mode) {
            case 'array' :
                $res = $query->fetchAll(PDO::FETCH_ASSOC);
                break;
            case 'object' :
                $res = $query->fetchObject();
                break;
            case 'count':
                $res = $query->rowCount();
                break;
            default:
                $this->showErrors("SQLERROR: please check your second param!");
            }
            return $res;
        }
        /**
        * 提示错误
        *
        * @param string $str 错误提示内容
        */
        public function showErrors($str)
        {
         
            echo "<h1>$str<h1/>";
            exit();
        }
    
    
    
    }

# ShowMessage.php #

<?php
    include("MyPdo.php");
    //连接Memcached服务器
    $m = new Memcached();
    $m->addServer('127.0.0.1',11211);
    //获取Memcached中的list
    $res = $m->get("list");
    //如果没有数据，则从数据库中查出，并放入Memcached中，如果有数据则直接输出
    if(!$res){
        $MyPdo = new MyPdo();
        $res = $MyPdo->query("select * from message","array");
        $m->set('list',$res,0,3600);
    }
    foreach($res as $val){
        echo $val['title']."-------".$val['content']."<br>";
    }
    ?>
    
    <a href="AddMessage.php">添加留言</a>

# AddMessage.php #

# CheckAdd.php #

<?php
    include("MyPdo.php");
    
    //连接Memcached服务器
    $m = new Memcached();
    $m->addServer('127.0.0.1',11211);
    
    $title = $_POST['title'];
    $content = $_POST['content'];
    
    $MyPdo = new MyPdo();
    $res = $MyPdo->query("insert into message(title,content) values('$title','$content')");
    if($res){
        //如果insert语句执行成功则清除Memcache中的缓存
        $m->delete("list");
    }
    
    header("location:ShowMessage.php");

运行结果如下所示：

![示例][20161011210108990]

![示例][20161011210143678]

注：此例子只是简单实现了，留言列表和添加留言功能，需要注意的是，如果对数据库的数据有了添加或修改，需要清除缓存，然后重新缓存一下，已保证数据显示同步。

[20161011210108990]: /images/20220716/21914e43b58146559b32ad69c976b6dc.png
[20161011210143678]: /images/20220716/729c859a340449bb968dfcd223c14ebf.png