如何在Symfony2服务类中访问Doctrine DBAL？

问题描述

我正在学习Symfony2（和OOP），并希望创建一个在我的应用程序中可用的服务。这个服务需要一个值foo，对数据库表进行检查，并返回值栏。

我有一个小课程

 命名空间Acme\TestBundle\Toolbox; 
 
 class StringToolbox 
 {
 public function lookupSomething（$ foo）
 {
 
 $ conn = $ this-> get（' database_connection'）; 
 $ sql =SELECT bar FROM bar_list WHERE foo =：foo; 
 $ stmt = $ conn-> prepare（$ sql）; 
 $ stmt-> bindValue（foo，$ foo）; 
 $ stmt-> execute（）; 
 
 
 return $ bar; 
} 
 
 
} 
  

我的设置是：

 服务：
工具箱：
类：Acme\TestBundle\Toolbox 
参数：[@database_connection] 
  

但是它会抛出一个错误，表示get（）方法未定义。我被卡住了 - 如何在服务中使用DBAL？谢谢！

解决方案

首先，你应该添加一个构造函数到你的课堂，并传入 @ doctrine.dbal。 ％connection_name％_connection service

 命名空间Acme\TestBundle\Toolbox; 
使用Doctrine\DBAL\Connection; 
 
 class StringToolbox 
 {
 / ** 
 * 
 * @var连接
 * / 
 private $ connection; 
 
 public function __construct（Connection $ dbalConnection）{
 $ this-> connection = $ dbalConnection; 
} 
 
 public function lookupSomething（$ foo）
 {
 
 $ sql =SELECT bar FROM bar_list WHERE foo =：foo; 
 $ stmt = $ this-> connection-> prepare（$ sql）; 
 $ stmt-> bindValue（foo，$ foo）; 
 $ stmt-> execute（）; 
 
 
 return $ bar; 
} 
 
 
} 
  

您的服务配置现在应该是这样的：

 参数：
 my_service_connection：默认
 
服务：
工具箱：
类：Acme\TestBundle\Toolbox\StringToolbox 
参数：[@ doctrine.dbal。％my_service_connection％_connection] 
  / pre> 
 
 
您使用此配置所说的内容是让我成为一个名为toolbox的服务，将接收doctrine.dbal.default_connection服务作为第一个构造函数
 
 
 
除了构造函数注入之外，还有其他注入方法，您应该阅读文档以了解所有可能性（Setter注入，工厂注入等），并更好地了解依赖注入如何工作
 
I'm learning Symfony2 (and OOP) and want to create a service that's available throughout my app.  This service takes a value foo, checks it against a database table, and returns a value bar.

I have a little class
namespace Acme\TestBundle\Toolbox;

class StringToolbox
{
    public function lookupSomething($foo)
   {

        $conn = $this->get('database_connection');
        $sql = "SELECT bar FROM bar_list WHERE foo = :foo";
        $stmt = $conn->prepare($sql);
        $stmt->bindValue("foo", $foo);
        $stmt->execute();


        return $bar;
    }


}
My settings are: 
services:
    toolbox:
       class:        Acme\TestBundle\Toolbox
        arguments:   [@database_connection]
But it throws an error saying that the get() method is undefined.  I'm stuck-- how can I use DBAL in the service?  Thanks! 
 解决方案 
First off you should add a constructor to your class and pass in the @doctrine.dbal.%connection_name%_connection service
namespace Acme\TestBundle\Toolbox;
use Doctrine\DBAL\Connection;

class StringToolbox
{
    /**
    *
    * @var Connection
    */
    private $connection;

    public function __construct(Connection $dbalConnection)  {
        $this->connection = $dbalConnection;
    }

    public function lookupSomething($foo)
    {

    $sql = "SELECT bar FROM bar_list WHERE foo = :foo";
    $stmt = $this->connection->prepare($sql);
    $stmt->bindValue("foo", $foo);
    $stmt->execute();


    return $bar;
    }


}
Your service configuration should now look like this:
parameters:
 my_service_connection: default

services:
 toolbox:
   class:        Acme\TestBundle\Toolbox\StringToolbox
    arguments:   [@doctrine.dbal.%my_service_connection%_connection]
What you are saying with this configuration is "make me a service named toolbox that will receive the doctrine.dbal.default_connection service as the first constructor argument"
There are other injection methods besides Constructor injection and you should read the http://symfony.com/doc/current/book/service_container.html documentation to get a grasp of all possibilities (Setter injection, Factory injection, etc) and to better understand how Dependency Injection works
                        
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