Detailed explanation of how to define PHP namespace namespace

This article mainly introduces the definition method of PHPnamespace, and analyzes the definition method and related methods of php namespace namespace and sub-namespace in detail in the form of examples.Notes, friends in need can refer to the following

The examples in this article describe the definition method of PHP namespace namespace. Share it with everyone for your reference. The details are as follows:

Define the namespace

For the naming of the space, I don’t want to explain it in words here. A better explanation is to use Example to prove:

For example:

The following code is the file in "test.php":

namespace Test;
class Test{
    public function Ttest(){
     echo "这是Test里面的测试方法"."<br>";
    }
}

Next I will Access in three different ways. I wrote these three access programs in a file named "index.php":

Method 1:

namespace Index;
require 'test.php';
$T=new \Test\Test();
$T->Ttest();

The result is:

This is the test method in Test

Method 2:

namespace Index;
namespace Test;
require 'test.php';
$T=new Test();
$T->Ttest();

The result obtained is:

This is the test method in Test

Method 3:

namespace Index;
require 'test.php';
use Test\Test;
$T=new Test();
$T->Ttest();

The result obtained For:

This is the test method in Test

Note: The namespace Index can be written or not. This is just the space name of the index.php file. The results obtained by these three methods are the same.

Define sub-namespaces

Definition:

Much like the relationship between directories and files, PHP namespaces also allow the specification of hierarchical namespaces The name. Therefore, namespace names can be defined in a hierarchical manner.

The example is as shown below. This is my customized project directory:

one.php

namespace projectOne\one;
class Test{
    public function test(){
     return "this is a test program";
    }
}

In order to access one.php The test() method under the Test class, my code in Two is as follows:

Two.php

namespace projectOne\one;
require '../projectOne/One.php';
$O=new Test();
echo $O->test();

Output: this is a test program

defined in the same file Multiple namespaces, they access each other

test.php

namespace projectOne\one{
    class test{
      public function hello(){
        return "helloworld";
      }
    }
}
namespace projectOne\Two{
    class project{
      public function world2(){
        return "welcome to china";
      }
    }
    class project2 extends \projectOne\one\test{
      public function wo(){
        return "this is my test function ,it is name wo";
      }
    }
}
namespace projectOne\Two{
    $p=new project2();
    echo $p->wo()."<br>";
    echo $p->hello();
}

output: this is my test function ,it is name wo
helloworld

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