php魔术方法（一）

PHP中的魔术方法

1.__get

用途：读取私有的成员属性,传入一个参数

例子：

<?php

Class Person
{
	private $_name = '花花';
	private $_age = 18;
	private $_sex = '女';
	
	public function __get($name)
	{
		$allowVars = ['_name','_age'];
		if (in_array($name,$allowVars)) {
			
			return $this->$name;
		}
	}
	
}
$p = new Person();
echo $p->_name;
echo $p->_age;
echo $p->_sex;

输出结果为

花花18

2.__set

用途：修改和设置私有的成员属性，两个参数（属性名，值）

例子：

<?php


Class Person
{
<span style="white-space:pre">	</span>private $_name = '花花';
<span style="white-space:pre">	</span>private $_age = 18;
<span style="white-space:pre">	</span>private $_sex = '女';

<span style="white-space:pre">	</span>public function __get($name)
<span style="white-space:pre">	</span>{
<span style="white-space:pre">		</span>return $this->$name;
<span style="white-space:pre">	</span>}
<span style="white-space:pre">	</span>public function __set($key,$value)
<span style="white-space:pre">	</span>{
<span style="white-space:pre">		</span>return $this->$key = $value;
<span style="white-space:pre">	</span>}

}
$p = new Person();
$p->_name = '小布';
echo $p->_name;

输出结果为

小布

注意：使用set方法时需要配合使用get方法

3.__unset

用途：删除和销毁私有成员属性时触发，一个参数

例子：

<?php


Class Person
{
<span style="white-space:pre">	</span>private $_name = '花花';
<span style="white-space:pre">	</span>private $_age = 18;
<span style="white-space:pre">	</span>private $_sex = '女';

<span style="white-space:pre">	</span>public function __get($name){
<span style="white-space:pre">		</span>return $this->$name;
<span style="white-space:pre">	</span>}

<span style="white-space:pre">	</span>public function __unset($name)
<span style="white-space:pre">	</span>{
<span style="white-space:pre">		</span>unset($this->$name);
<span style="white-space:pre">	</span>}

}
$p = new Person();
unset($p->_name);
echo $p->_name;

输出结果为

空

4.__isset

用途：删除和销毁私有成员属性时触发，一个参数

例子：

<?php


Class Person
{
<span style="white-space:pre">	</span>private $_name = '花花';
<span style="white-space:pre">	</span>private $_age = 18;
<span style="white-space:pre">	</span>private $_sex = '女';

<span style="white-space:pre">	</span>public function __isset($name)
<span style="white-space:pre">	</span>{
<span style="white-space:pre">		</span>if (isset($this->$name)) {
<span style="white-space:pre">		</span>echo '设置过';
<span style="white-space:pre">		</span>} else {
<span style="white-space:pre">		</span>echo '未设置过';
<span style="white-space:pre">		</span>}
<span style="white-space:pre">	</span>}

}
$p = new Person();
isset($p->_name);
isset($p->_home);

输出结果为

设置过 未设置过

3.__construct

用途：实例化一个对象时自动执行，参数自己规定

例子：

<?php


Class Person
{
<span style="white-space:pre">	</span>private $_name;
<span style="white-space:pre">	</span>private $_age;
<span style="white-space:pre">	</span>private $_sex;
<span style="white-space:pre">	</span>
<span style="white-space:pre">	</span>public function __construct($name,$age,$sex)
<span style="white-space:pre">	</span>{
<span style="white-space:pre">		</span>$this->_name = $name;
<span style="white-space:pre">		</span>$this->_age = $age;
<span style="white-space:pre">		</span>$this->_sex = $sex;
<span style="white-space:pre">	</span>}
<span style="white-space:pre">	</span>public function __get($name)
<span style="white-space:pre">	</span>{
<span style="white-space:pre">		</span>return $this->$name;
<span style="white-space:pre">	</span>}
<span style="white-space:pre">	</span>
}
$p = new Person('花花',18,'女');
echo $p->_name;
echo $p->_age;

输出结果为

<span style="font-size:12px;">花花18</span>