Php 如何使用Symfony对Csv进行编码

我使用的是serializer组件的symfony，这里有一个将序列化和对象转换为JSON格式的示例，接下来：

    $encoders = array(new XmlEncoder(), new JsonEncoder());
    $normalizers = array(new ObjectNormalizer());

    $person = new \AppBundle\Entity\Person();
    $person->setName('foo');
    $person->setAge(99);
    $person->setSportsman(false);

    // return new JsonResponse($person); // empty

    $serializer = new Serializer($normalizers, $encoders);

    /**
     * 1 param - object to be serialized
     * 2 param - proper encoder, in this case JsonEncoder
     * @var [type]
     */
    $jsonContent = $serializer->serialize($person, 'json');

    return new Response($jsonContent);

上面的示例返回如下内容：

{"id":null,"age":99,"name":"foo","sportsman":false}

---

但是我想知道如何做同样的事情，从Symfony 3.2开始，CSV和YAML编码器被添加到了

CSV

，而不是

JSON

// instantiation, when using it as a component
use Symfony\Component\Serializer\Serializer;
use Symfony\Component\Serializer\Encoder\CsvEncoder;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;

$serializer = new Serializer([new ObjectNormalizer()], [new CsvEncoder()]);

// instantiation, when using it inside the Symfony framework
$serializer = $container->get('serializer');

// encoding contents in CSV format
$serializer->encode($data, 'csv');

// decoding CSV contents
$data = $serializer->decode(file_get_contents('data.csv'), 'csv');

---

您可以在那里找到更多信息：

自Symfony 3.2以来添加了CSV和YAML编码器

// instantiation, when using it as a component
use Symfony\Component\Serializer\Serializer;
use Symfony\Component\Serializer\Encoder\CsvEncoder;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;

$serializer = new Serializer([new ObjectNormalizer()], [new CsvEncoder()]);

// instantiation, when using it inside the Symfony framework
$serializer = $container->get('serializer');

// encoding contents in CSV format
$serializer->encode($data, 'csv');

// decoding CSV contents
$data = $serializer->decode(file_get_contents('data.csv'), 'csv');

---

您可以在那里找到更多信息：

？？？？？我尝试了相同的代码，但得到了一个空数组。第一个$serializer变量的用途是什么？我尝试了相同的代码，但得到了一个空数组。第一个$serializer变量的用途是什么？