PHP析构方法 __destruct() 不触发的两个解决办法-php教程

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本篇文章次要给各人引见PHP 析构办法 __destruct() 没有触发的两个处理方法。

有时分正在 PHP 里类轮回援用时,会招致 __destruct() 没有触发的成绩,先上成绩代码:

<?php
class Proxy
{
    private $object;
 
    public function __construct($object)
    {
        $this->object = $object;
    }
 
    public function __destruct()
    {
        var_dump('__destruct:Proxy');
    }
}
 
class Test
{
    private $proxy;
 
    public function __construct()
    {
        $this->proxy = new Proxy($this);
    }
 
    public function __destruct()
    {
        var_dump('__destruct:Test');
    }
}
 
$test = new Test;
unset($test);
 
echo 'no __destruct, wait 3s', PHP_EOL;
 
sleep(3);
 
echo '__destruct now:', PHP_EOL;

如上代码,运转unset($test)时,没有会触发__destruct(),由于有了轮回援用。

再看上面的处理办法1的代码:

<?php
class Proxy
{
    private $object;
 
    public function __construct($object)
    {
        $this->object = $object;
    }
 
    public function __destruct()
    {
        var_dump('__destruct:Proxy');
    }
}
 
class Test
{
    private $proxy;
 
    public function __construct()
    {
        $this->proxy = new Proxy($this);
    }
 
    public function __destruct()
    {
        var_dump('__destruct:Test');
    }
 
    public function close()
    {
        $this->proxy = null;
    }
}
 
$test = new Test;
$test->close();
 
echo '__destruct now:', PHP_EOL;
 
unset($test);
 
sleep(3);
 
echo 'no operation', PHP_EOL;

下面的代码,正在unset以前,将Test类中的proxy设为null,而后再unset,就能够触发__destruct()了。

当然,你也能够手动gc(处理办法2):

<?php
class Proxy
{
    private $object;
 
    public function __construct($object)
    {
        $this->object = $object;
    }
 
    public function __destruct()
    {
        var_dump('__destruct:Proxy');
    }
}
 
class Test
{
    private $proxy;
 
    public function __construct()
    {
        $this->proxy = new Proxy($this);
    }
 
    public function __destruct()
    {
        var_dump('__destruct:Test');
    }
}
 
$test = new Test;
unset($test);
 
echo '__destruct now:', PHP_EOL;
gc_collect_cycles();
 
sleep(3);
 
echo 'no operation', PHP_EOL;

心愿对需求的冤家有所协助!

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