PHP SplObjectStorage使用实例

PHP SPL SplObjectStorage是用来存储一组对象的，特别是当你需要唯一标识对象的时候。
PHP SPL SplObjectStorage类实现了Countable,Iterator,Serializable,ArrayAccess四个接口。可实现统计、迭代、序列化、数组式访问等功能。

看下面一个简单的例子：

class A {  public $i;  public function __construct($i) {    $this->i = $i;  }} $a1 = new A(1);$a2 = new A(2);$a3 = new A(3);$a4 = new A(4); $container = new SplObjectStorage(); //SplObjectStorage::attach 添加对象到Storage中$container->attach($a1);$container->attach($a2);$container->attach($a3); //SplObjectStorage::detach 将对象从Storage中移除$container->detach($a2); //SplObjectStorage::contains用于检查对象是否存在Storage中var_dump($container->contains($a1)); //truevar_dump($container->contains($a4)); //false //遍历$container->rewind();while($container->valid()) {  var_dump($container->current());  $container->next();}