PHP面向对象之后期静态绑定功能介绍_php实例
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2022-05-29 11:02:28
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本文将对PHP后期静态绑定功能进行介绍,它主要用于解决在继承范围内引用静态调用的类。
class Person
{
public static function status()
{
self::getStatus();
}
protected static function getStatus()
{
echo "Person is alive";
}
}
class Deceased extends Person
{
protected static function getStatus()
{
echo "Person is deceased";
}
}
Deceased::status(); //Person is alive
class Person
{
public static function status()
{
static::getStatus();
}
protected static function getStatus()
{
echo "Person is alive";
}
}
class Deceased extends Person
{
protected static function getStatus()
{
echo "Person is deceased";
}
}
Deceased::status(); //Person is deceased
首先来看下面这个例子:
复制代码 代码如下:
class Person
{
public static function status()
{
self::getStatus();
}
protected static function getStatus()
{
echo "Person is alive";
}
}
class Deceased extends Person
{
protected static function getStatus()
{
echo "Person is deceased";
}
}
Deceased::status(); //Person is alive
很明显,结果不是我们预期的,这是因为self::取决于定义时所在的类,而不是运行中的类。为了解决这个问题,你可能会在继承类中重写status()方法,更好的解决方案是PHP 5.3后添加了后期静态绑定的功能。
复制代码 代码如下:
class Person
{
public static function status()
{
static::getStatus();
}
protected static function getStatus()
{
echo "Person is alive";
}
}
class Deceased extends Person
{
protected static function getStatus()
{
echo "Person is deceased";
}
}
Deceased::status(); //Person is deceased
可见,static::不在指向当前所在的类,实际上,它是在运行中计算的,强制获取最终类的所有属性。
因此,建议,以后不要再使用self::,使用static::