找不到PHP名称空间PDO [英] PHP namespace PDO not found

问题描述

我面临的问题是我迄今为止无法解决的.我在app/db/mysql/database.php中创建了一个database class，其内容如下:

I'm facing an issue I unfortunatly could not resolve so far. I created a database class into app/db/mysql/database.php with the following content :

<?php
    namespace App\Database;
    use Symfony\Component\Yaml\Yaml;

    class Database{
        private static $connection = null;

        private function __construct( $host, $base, $user, $pass ){
            try{
                self::$connection = new PDO("mysql:host=$host;dbname=$base", $user, $pass);
            }catch(PDOException $e){
                die($e->getMessage());
            }
        }

        public static function get(){
            if( self::$connection !== null ){
                return self::$connection;
            }
            $yaml = Yaml::parse(file_get_contents(realpath('./app') . '/database.yml'));
            self::$connection = new Database( $yaml['host'], $yaml['base'], $yaml['user'], $yaml['pass'] );
        }
    }

使用作曲家，我正在自动加载此类:

Using composer, I'm autoloading this class :

{
    "autoload" : {
        "classmap" : [
            "app/libraries",
            "app/db"
        ]
    }
}

会生成autoload_classmap.php，例如:

return array(
    'App\\Database\\Database' => $baseDir . '/app/db/mysql/database.php',
    'App\\Libraries\\Parser' => $baseDir . '/app/libraries/Parser.php',
);

现在，当一切正常时，我总是收到与PDO相关的错误:

Now, when everything works fine, I'm always getting an error related to PDO :

Fatal error: Class 'App\Database\PDO' not found in /var/www/my_application/app/db/mysql/database.php on line 24

我认为问题出在namespace，因为当我将类放入索引页面时，我没有任何错误. PDO已安装并正常工作.

I think the problem comes from namespace because when I put the class into the index page, I don't have any error. PDO is installed and works.

推荐答案

问题已经过编辑，但是对于那些直接回答问题的人来说，就在这里.

您应该为方法中的对象使用正确的名称空间，或者使用"它们或为它们添加根名称空间；

You should be using correct namespaces for the objects in your methods, either "use" them or prefix them with the root namespace;

<?php
//... namespace etc...

use \PDO;

self::$connection = new PDO("mysql:host=$host;dbname=$base", $user, $pass);

或简单地

self::$connection = new \PDO("mysql:host=$host;dbname=$base", $user, $pass);

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