PHP Magic Method __construct __destruct (i)

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__construct ()-this method is called each time a new object is created

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

<?php/** * Clear understanding of __construct () __destruct */class Example {public    static $link;    This method is loaded automatically when the class is instantiated __construct public    function __construct ($localhost, $username, $password, $db) {        self::$ link = mysql_connect ($localhost, $username, $password);        if (Mysql_errno ()) {die            (' ERROR: '. mysql_error ());        }        Mysql_set_charset (' UTF8 ');        mysql_select_db ($DB);    }    /**     * Link the database by __construct and execute the SQL statement     ... *////        when the class needs to be deleted or destroyed this class is automatically loaded __destruct this method public    function __destruct () {        echo ' <pre> ';        Var_dump (self:: $link);        Mysql_close (self:: $link);        Var_dump (self:: $link);    }} $mysql = new Example (' localhost ', ' root ', ' root ', ' test ');

Results:

Resource (2) of type (MySQL link) resource (2) of type (Unknown)

　　

PHP Magic Method __construct __destruct (i)