PHP中abstract种中有abstract方法是否最先执行abstract方法，然后才执行其他方法

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发布： 2016-06-13 12:54:59

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PHP中abstract类中有abstract方法是否最先执行abstract方法，然后才执行其他方法？
rt

<br />
abstract class Node {<br />
		private $debugMessages;<br />
		<br />
		public function __construct() {<br />
			$this->debugMessages = array();<br />
			$this->debug(__CLASS__.' constructor called.');<br />
		}<br />
		<br />
		public function __destruct() {<br />
			$this->debug(__CLASS__.' destructor called.');<br />
			$this->dumpDebug();<br />
		}<br />
		<br />
		protected function debug($msg) {<br />
			$this->debugMessages[] = $msg;<br />
		}<br />
		<br />
		private function dumpDebug() {<br />
			echo implode('<br />', $this->debugMessages);<br />
		}<br />
		<br />
		public abstract function getView();<br />
	}<br />
	<br />
	<br />
	class ForumTopic extends Node {<br />
		private $debugMessages;<br />
		<br />
		public function __construct() {<br />
			parent::__construct();<br />
			$this->debug(__CLASS__.' constructor called.');<br />
		}<br />
		<br />
		public function __destruct() {<br />
			$this->debug(__CLASS__.' destructor called.');<br />
			parent::__destruct();<br />
		}<br />
		<br />
		public function getView() {<br />
			return 'This is a view into '.__CLASS__.'<br />';<br />
		}<br />
	}<br />
	<br />
	$forum = new ForumTopic();<br />
	echo $forum->getView();<br />

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执行结果：
This is a view into ForumTopic
Node constructor called.
ForumTopic constructor called.
ForumTopic destructor called.
Node destructor called.

但没有new ForumTopic()怎么能够调用执行getView()？

php destructor constructor function class
------解决方案--------------------
执行顺序:
ForumTopic::__construct()
Node::__construct()
Node::debug()
ForumTopic::debug()
ForumTopic::getView()
ForumTopic::__destruct()
ForumTopic::debug()
Node::__destruct()
Node::debug()
Node::dumpDebug()
------解决方案--------------------
不知道你想说啥，哪个先调用就执行哪个。
你是先执行echo $forum->getView();所以先输出：This is a view into ForumTopic
在对象的销毁的时候，父类析构函数把$debugMessages中的所有数据打印出来了。就下面那样：
Node constructor called.
ForumTopic constructor called.
ForumTopic destructor called.
Node destructor called.

__CLASS__指是的当前类

get_class($obj)指的是实例$obj的类

------解决方案--------------------
如果你把
protected function debug($msg) {
            $this->debugMessages[] = $msg;
        }
改成
protected function debug($msg) {
           echo $msg;
        }
你就可以看到真正的执行顺序

------解决方案--------------------

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