设计模式-PHP实现单件模式的几种方式
单件模式是我们在开发中经常用到的一种设计模式,利用PHP5面向对象的特性,我们可以很容易的构建单件模式的应用,下面是单件模式在PHP中的几种实现方法:
class Stat{
static $instance = NULL;
static function getInstance(){
if(self::$instance == NULL){
self::$instance = new Stat();
}
return self::$instance;
}
private function __construct(){
}
private function __clone(){
}
function sayHi(){
return "The Class is saying hi to u
";
}
}
echo Stat::getInstance()->sayHi();
static $instance = NULL;
static function getInstance(){
if(self::$instance == NULL){
self::$instance = new Stat();
}
return self::$instance;
}
private function __construct(){
}
private function __clone(){
}
function sayHi(){
return "The Class is saying hi to u
![](https://www.cnblogs.com/Images/dot.gif)
}
}
echo Stat::getInstance()->sayHi();
这是一种最通常的方式,在一个getInstance方法中返回唯一的类实例。
对这里例子稍加修改,便可以产生一个通用的方法,只要叫道任何你想用到单件的类里,就可以了。
class Teacher{
function sayHi(){
return "The teacher smiling and said 'Hello
'";
}
static function getInstance(){
static $instance;
if(!isset($instance)){
$c = __CLASS__;
$instance = new $c;
}
return $instance;
}
}
echo Teacher::getInstance()->sayHi();
function sayHi(){
return "The teacher smiling and said 'Hello
![](https://www.cnblogs.com/Images/dot.gif)
}
static function getInstance(){
static $instance;
if(!isset($instance)){
$c = __CLASS__;
$instance = new $c;
}
return $instance;
}
}
echo Teacher::getInstance()->sayHi();
最后一种是提供一个singleton类,然后通过调用getInstance方法,可以为任何一个类生产出一个实例来。
class singleton{
function getInstance($class){
static $instances = array();
if(!array_key_exists($class,$instances)){
$instances[$class] = &new $class;
}
$instance = $instances[$class];
return $instance;
}
}
class People{
function sayHi(){
return 'Hello i am a people?';
}
}
echo "<br />";
echo singleton::getInstance('People')->sayHi();
function getInstance($class){
static $instances = array();
if(!array_key_exists($class,$instances)){
$instances[$class] = &new $class;
}
$instance = $instances[$class];
return $instance;
}
}
class People{
function sayHi(){
return 'Hello i am a people?';
}
}
echo "<br />";
echo singleton::getInstance('People')->sayHi();
通过这三种方法,我们可以很容易的应用单件模式,如果能够结合工厂模式,将使我们的编程变得更有条理和效率。