享元模式的设计思想是尽量复用已创建的对象，常用于工厂方法内部的优化
因此，享元模式就是通过工厂方法创建对象，在工厂方法内部，很可能返回缓存的实例，而不是新创建实例，从而实现不可变实例的复用
class student{
public $id;
public $name;
private $redis;
public function __construct($id, $name){
$this->id = $id;
$this->name = $name;
$redis = new \Redis();
$redis->connect('127.0.0.1', 6379);
$this->redis = $redis;
}
public function create(){
$cacheKey = 'student' . $this->id;
$tmpGet = $this->redis->get($cacheKey);
if(!$tmpGet){
echo 'create new student' . PHP_EOL;
$student = new student($this->id, $this->name);
$this->redis->set($cacheKey, serialize($student));
}else{
echo 'from cache' . PHP_EOL;
$student = unserialize($tmpGet);
echo $student->id . ' name is : ' . $student->name;
}
return $student;
}
}
$obj = new student(1, 'tom');
$result = $obj->create();
