1.說明

1.適配器模式： 可以將截然不同的函數(shù)接口封裝成統(tǒng)一的API
2.實(shí)際應(yīng)用舉例，PHP的數(shù)據(jù)庫操作有mysql, mysqli, pdo3種，可以用適配器模式統(tǒng)一成一致。類似的場景還有cache適配器，就是將memcache，redis，file，apc等不同的緩存函數(shù)統(tǒng)一成一致的
3.下面的例子可以幫助你對付各種數(shù)據(jù)庫鏈接功能，mysql mysqli, pdo隨便選，操作都抽象為統(tǒng)一的接口客戶端不需要修改一行數(shù)據(jù)庫鏈接方式

2.創(chuàng)建一個(gè)接口

interface IDatabase{    function connect($host, $user, $passwd, $dbname);    function query($sql);    function close();}

3.Mysql封裝

html' target='_blank'>class MySQL implements IDatabase{    protected $conn;    function connect($host, $user, $passwd, $dbname)    {        $conn = mysql_connect($host, $user, $passwd);        mysql_select_db($dbname, $conn);        $this->conn = $conn;    }    function query($sql)    {        $res = mysql_query($sql, $this->conn);        return $res;    }    function close()    {        mysql_close($this->conn);    }}

4.MySqli封裝

class MySQLi implements IDatabase{    protected $conn;    function connect($host, $user, $passwd, $dbname)    {        $conn = mysqli_connect($host, $user, $passwd, $dbname);        $this->conn = $conn;    }    function query($sql)    {        return mysqli_query($this->conn, $sql);    }    function close()    {        mysqli_close($this->conn);    }}

5.PDO封裝

class PDO implements IDatabase{    protected $conn;    function connect($host, $user, $passwd, $dbname)    {        $conn = new PDO('mysql:host=$host;dbname=$dbname', $user, $passwd);        $this->conn = $conn;    }    function query($sql)    {        return $this->conn->query($sql);    }    function close()    {        unset($this->conn);    }}

6.實(shí)例調(diào)用，（統(tǒng)一接口調(diào)用）

$db = new PDO();$db->connect('127.0.0.1', 'root', 'root', 'test');$db->query('show databases');$db->close();$db = MySQLi ();$db->connect('127.0.0.1', 'root', 'root', 'test');$db->query('show databases');$db->close();$db = MySQl PDO();$db->connect('127.0.0.1', 'root', 'root', 'test');$db->query('show databases');$db->close();

PHP編程

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