如何在PHP中使用带有命名空间的类?

问题描述：

我尝试创建具有以下结构的应用程序:

I try to create app with structure as below:

App
 +--src
      Example.php
 +--vendor
    --
 composer.json
 composer.lock
 index.php

在Example.php设置了 namespace Example 的位置，然后在 index.php 中使用它.但它不起作用.

Where Example.php set namespace Example then use it inside index.php. but it not working.

Example.php

<?php namespace Example

class Example {
    public function __construct()
    {
        echo 'constructed';
    }
}

index.php

<?php use Example\Example;

$example = new Example;

echo 'here ok';

但是当我在浏览器中运行它时，它的错误:

but when I runing it in browser, its error:

我怎么了，有什么帮助吗?

What am I wrong, any help?

答

由于您尚未发布 composer.json 所包含的内容，因此至少必须将其保存在 autoload中:

Since you haven't posted what your composer.jsoncontains yet, at least you must have it in your autoload:

{
    "autoload": {
        "psr-4": {
            "Example\\": "src"
        }
    }
}

在您的 index.php 中，您需要从composer中自动加载:

In your index.php, you need to require the autoload from composer:

require_once 'vendor/autoload.php'; // add the autoloader

use Example\Example;

$example = new Example;

echo 'here ok';

最后，您需要运行composer来反映您的更改:

Lastly, you need to run composer to reflect your changes:

php composer dump-autoload