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Instructions for using class-level constants in php5.5_PHP Tutorial

WBOYOriginal: 2016-07-13 17:16:421031browse

I studied php5.5 yesterday and found that there is a new feature called class-level constants. Let me briefly share my study notes with you.

Not long ago, PHP released the first stable version of 5.5, which introduced a class-level constant named `CLASS`. This constant is valid for all classes and returns the full name of the class.

The code is as follows

代码如下	复制代码
namespace vendorpackage; class Foo { // ... } var_dump(Foo::CLASS); //上面脚本输出 string(18) "vendorpackageFoo".

Copy code

namespace vendorpackage;
class Foo
{
// ...
}
var_dump(Foo::CLASS);
//The above script outputs string(18) "vendorpackageFoo".

代码如下	复制代码
namespace vendorpackage; class Foo { // ... } var_dump(__NAMESPACE__ . 'Foo');

Why use it

Why should we use such a constant? Of course it is not just to get the full name of the class like the example above. We can also achieve the same effect using __NAMESPACE__, and php5.3 can be used:

The code is as follows

Copy code

代码如下	复制代码
use vendorpackageFoo; class FooTest extends PHPUnit_Framework_TestCase { public function testBarCanBeProcessed() { $bar = $this->getMock('vendorpackageBar'); $foo = new Foo; $foo->process($bar); // ... } }

namespace vendorpackage;
class Foo
{
// ...
}
var_dump(__NAMESPACE__ . 'Foo');

代码如下	复制代码
use vendorpackageFoo; use vendorpackageBar; class FooTest extends PHPUnit_Framework_TestCase { public function testBarCanBeProcessed() { $bar = $this->getMock(Bar::CLASS); $foo = new Foo; $foo->process($bar); // ... } }

However, when you need to fully qualify the name, the namespace references the class namespace alias... then it gets interesting

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