使用名称空间时找不到PHP类 [英] PHP class not found when using namespace

问题描述

我是这个命名空间的新手.

I am new with this namespace thing.

我的基本目录中有2个类(单独的文件)，例如目录src/中的class1.php和class2.php.

I have 2 classes(separate files) in my base directory, say class1.php and class2.php inside a directory src/.

class1.php

namespace \src\utility\Timer;

class Timer{
    public static function somefunction(){

    }
}

class2.php

namespace \src\utility\Verification;
use Timer;

class Verification{
     Timer::somefunction();
}

执行class2.php时，出现致命错误

PHP致命错误:在path/to/class2.php中找不到类"Timer" ***行

PHP Fatal error: Class 'Timer' not found in path/to/class2.php at line ***

我在SO上的某处读到了我需要为此创建Autoloader的信息.如果是这样，我该如何创建一个，如果不是，那么还有什么问题呢?

I read somewhere on SO, that I need to create Autoloaders for this. If so, how do I approach into creating one, and if not, then what else is the issue?

更新

我创建了一个自动加载器，它将在我的PHP脚本顶部require所有必需的文件. 因此，现在class2.php最终会像这样.

I created an Autoloader which will require all the required files on top of my php script. So, now the class2.php would end up like this.

namespace \src\utility\Verification;
require '/path/to/class1.php'
use Timer;
//or use src\utility\Timer ... both doesn't work.

class Verification{
     Timer::somefunction();
}

这也不起作用，它表明找不到该类.但是，如果我删除所有的namespaces和use.一切正常.

This also does not work, and it shows that class not found. But, if I remove all the namespaces, and use's. Everything works fine.

推荐答案

我们可以通过两种方式解决名称空间问题

We can solve the namespace problem in two ways

1)我们可以只使用名称空间并要求

2)我们可以使用Composer并进行自动加载！

第一种方式(命名空间和要求)

Class1.php(计时器类)

Class1.php (Timer Class)

namespace Utility;

class Timer
   {
    public static function {}
   }

Class2.php(验证类)

Class2.php (Verification Class)

namespace Utility;
require "Class1.php";

//Some interesting points to note down!
//We are not using the keyword "use" 
//We need to use the same namespace which is "Utility" 
//Therefore, both Class1.php and Class2.php has "namespace Utility"

//Require is usually the file path!
//We do not mention the class name in the require " ";
//What if the Class1.php file is in another folder?
//Ex:"src/utility/Stopwatch/Class1.php"  

//Then the require will be "Stopwatch/Class1.php"
//Your namespace would be still "namespace Utility;" for Class1.php

class Verification
   {
     Timer::somefunction();
   }

第二种方式(使用Composer和自动加载方式)

制作 composer.json 文件.根据您的示例"src/Utility" 我们需要在src文件夹之前创建一个composer.json文件.示例:在名为myApp的文件夹中，您将拥有composer.json文件和src文件夹.

Make composer.json file. According to your example "src/Utility" We need to create a composer.json file before the src folder. Example: In a folder called myApp you will have composer.json file and a src folder.

   {
     "autoload": {
     "psr-4": {
        "Utility\\":"src/utility/"
        }
     }   
   }

现在转到该文件夹​​，在有composer.json文件的文件夹位置中打开您的终端.现在输入终端！

Now go to that folder open your terminal in the folder location where there is composer.json file. Now type in the terminal!

   composer dump-autoload

这将创建一个供应商文件夹.因此，如果您有一个名为"MyApp"的文件夹 您将看到供应商文件夹，src文件夹和composer.json文件

This will create a vendor folder. Therefore if you have a folder named "MyApp" you will see vendor folder, src folder and a composer.json file

Timer.php(计时器类)

Timer.php(Timer Class)

namespace Utility;

class Timer
     {
      public static function somefunction(){}
     }

Verification.php(验证类)

Verification.php (Verification Class)

namespace Utility; 
require "../../vendor/autoload.php"; 
use Utility\Timer; 

class Verification
  {
     Timer::somefunction(); 
  }

当您具有复杂的文件夹结构时，此方法将更强大！！

This method is more powerful when you have a complex folder structure!!

这篇关于使用名称空间时找不到PHP类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！