PHP singleton mode sample sharing, PHP mode sample sharing _php Tutorial

PHP singleton mode sample sharing, PHP pattern sample sharing

The singleton mode is primarily used for database connections, ensuring that the database has only one instance of a class and provides this instance to the entire system. This prevents new operations from consuming resources while avoiding too many connection information in the database.

There are three points: 1. There must be only one instance. 2. This instance must be created automatically. 3. This instance must be provided to the system as a whole.

Copy the Code code as follows:
<?
Class mysql{
Privete static $instance;//Save Instance
The constructor is declared private, preventing the object from being created directly
Privete function __construct () {
Instantiation of
}
A singleton method that determines if it has been instantiated and instantiates only once
public static function getinstance () {
if (!isset (self:: $instance)) {
Self:: $instance = new self ();
}
Return self:: $instance;
}
Prevent cloning objects
Private Function __clone () {
Trigger_error ("not allow to clone.");
}
function Test () {
echo "Test";
}
}
$conn = Mysql::getinstance ();
$conn->test ();
?>

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