PHP magic method __construct __destruct (1), phpdestruct_PHP tutorial

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

<?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');

Result:

resource(2) of type (mysql link)
resource(2) of type (Unknown)

　

http://www.bkjia.com/PHPjc/916824.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/916824.htmlTechArticlePHP magic method __construct __destruct (1), phpdestruct slowly looking for the night, the bright moon hanging high in the sky __construct() - Call this method __destruct() first every time you create a new object - All the objects...