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Homephp教程php手册PHP里的单例类写法实例,PHP类写法实例

PHP里的单例类写法实例,PHP类写法实例

PHP里的单实例类在进行数据交换,节省内存上还是很有意义的。写个简单例子。
类1,单实例类本身:

class UTIL {
  private static $instance;
  public function get() {
    if (!self::$instance) {
      self::$instance = new UTIL();
    }
    return self::$instance;
  }
  public $number = 10;
  public function change($num) {
    $this->number += $num;
  }
  public function getNum() {
    return $this->number;
  }
}

类2,使用前述单实例类的应用类:

class SINGLEA {
  private $numInst;
  function __construct() {
    $this->numInst = UTIL::get();
  }
  public function change($num) {
    $this->numInst->change($num);
  }
  public function getNum() {
    return $this->numInst->getNum();
  }
}

类3,同类2:

class SINGLEB {
  private $numInst;
  function __construct() {
    $this->numInst = UTIL::get();
  }
  public function change($num) {
    $this->numInst->change($num);
  }
  public function getNum() {
    return $this->numInst->getNum();
  }
}

最后是调用的地方:

$instA = new SINGLEA();
$instA->change(100);
var_dump('SINGLEA CHANGED: ');
var_dump($instA->getNum());
$instB = new SINGLEB();
$instB->change(-510);
var_dump('SINGLEB CHANGED: ');
var_dump($instB->getNum());

最后的显示结果:

string'SINGLEA CHANGED: ' (length=17)
int110
string'SINGLEB CHANGED: ' (length=17)
int-400

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