php 找出静态类中是否存在方法
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Find out if a method exists in a static class
提问by Tyler Carter
I want to check is a function exists in a library that I am creating, which is static. I've seen function and method_exists, but haven't found a way that allows me to call them in a relative context. Here is a better example:
我想检查我正在创建的库中是否存在一个函数，它是静态的。我见过 function 和 method_exists，但还没有找到一种方法可以让我在相对上下文中调用它们。这是一个更好的例子：
class myClass{
function test1()
{
if(method_exists("myClass", "test1"))
{
echo "Hi";
}
}
function test2()
{
if(method_exists($this, "test2"))
{
echo "Hi";
}
}
function test3()
{
if(method_exists(self, "test3"))
{
echo "Hi";
}
}
}
// Echos Hi
myClass::test1();
// Trys to use 'self' as a string instead of a constant
myClass::test3();
// Echos Hi
$obj = new myClass;
$obj->test2();
I need to be able to make test 3 echo Hi if the function exists, without needing to take it out of static context. Given the keyword for accessing the class should be 'self', as $this is for assigned classes.
如果该函数存在，我需要能够使 test 3 echo Hi，而无需将其从静态上下文中取出。鉴于访问类的关键字应该是“self”，因为 $this 用于分配的类。
回答by gapple
static::classis available since PHP 5.5, and will return the "Late Static Binding" class name:
static::class自 PHP 5.5 起可用，并将返回“ Late Static Binding”类名：
class myClass {
public static function test()
{
echo static::class.'::test()';
}
}
class subClass extends myClass {}
subClass::test() // should print "subClass::test()"
get_called_class()does the same, and was introduced in PHP 5.3
get_called_class()做同样的事情，并在 PHP 5.3 中引入
class myClass {
public static function test()
{
echo get_called_class().'::test()';
}
}
class subClass extends myClass {}
subClass::test() // should print "subClass::test()"
The get_class()function, which as of php 5.0.0 does not require any parameters if called within a class will return the name of the class in which the function was declared (e.g., the parent class):
该get_class()函数，从 php 5.0.0 开始，如果在类中调用，则不需要任何参数，将返回声明该函数的类的名称（例如，父类）：
class myClass {
public static function test()
{
echo get_class().'::test()';
}
}
class subClass extends myClass {}
subClass::test() // prints "myClass::test()"
The __CLASS__magic constantdoes the same [link].
该__CLASS__魔术不断做同样[链接]。
class myClass {
public static function test()
{
echo __CLASS__.'::test()';
}
}
class subClass extends myClass {}
subClass::test() // prints "myClass::test()"
回答by hobodave
Update:
更新：
Ahh, apologies. I was temporarily blind :) You'll want to use the magic constant __CLASS__
啊，抱歉。我暂时失明了 :) 你会想要使用魔法常量 __CLASS__
e.g.
例如
if (method_exists(__CLASS__, "test3")) { echo "Hi"; }
回答by sxn
for all situations… the best usage would be…
对于所有情况……最好的用法是……
if method_exist(…) && is_callable(…)
For testing example:
对于测试示例：
class Foo {
public function PublicMethod() {}
private function PrivateMethod() {}
public static function PublicStaticMethod() {}
private static function PrivateStaticMethod() {}
}
$foo = new Foo();
$callbacks = array(
array($foo, 'PublicMethod'),
array($foo, 'PrivateMethod'),
array($foo, 'PublicStaticMethod'),
array($foo, 'PrivateStaticMethod'),
array('Foo', 'PublicMethod'),
array('Foo', 'PrivateMethod'),
array('Foo', 'PublicStaticMethod'),
array('Foo', 'PrivateStaticMethod'),
);
foreach ($callbacks as $callback) {
var_dump($callback);
var_dump(method_exists($callback[0], $callback[1])); // 0: object / class name, 1: method name
var_dump(is_callable($callback));
echo str_repeat('-', 40), "n";
}
Source here
来源在这里
