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PHP magic method __construct __destruct (1), phpdestruct
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PHP magic method __construct __destruct (1), phpdestruct_PHP tutorial

Jul 13, 2016 am 10:13 AM
Underline

PHP magic method __construct __destruct (1), phpdestruct

Slowly looking for the night, the bright moon hangs high in the sky

__construct() - This method is called first every time a new object is created

__destruct() - All references to the object are deleted or executed when the object is explicitly destroyed

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<?php

 

/**

 * 清晰的认识__construct() __destruct

 */

class Example {

 

    public static $link;

    //在类实例化的时候自动加载__construct这个方法

    public function __construct($localhost, $username, $password, $db) {

        self::$link = mysql_connect($localhost, $username, $password);

        if (mysql_errno()) {

            die('错误:' . mysql_error());

        }

        mysql_set_charset('utf8');

        mysql_select_db($db);

    }

 

    /**

     * 通过__construct链接好数据库然后执行sql语句......

     */

     

    //当类需要被删除或者销毁这个类的时候自动加载__destruct这个方法

    public function __destruct() {

        echo '<pre class="brush:php;toolbar:false">';

        var_dump(self::$link);

        mysql_close(self::$link);

        var_dump(self::$link);

    }

 

}

 

$mysql = new Example('localhost', 'root', 'root', 'test');

Copy after login

Result:

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resource(2) of type (mysql link)

resource(2) of type (Unknown)

Copy after login

 

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