Slowly long search night, the moon hanging
__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)