我认为使用trait来存储对象到数组的转换逻辑是一个不错的想法。举个简单的例子:

trait ArrayAwareTrait
{
    /**
     * Return list of Entity's parameters
     * @return array
     */
    public function toArray()
    {
        $props = array_flip($this->getPropertiesList());
        return array_map(
            function ($item) {
                if ($item instanceof \DateTime) {
                    return $item->format(DATE_ATOM);
                }
                return $item;
            },
            array_filter(get_object_vars($this), function ($key) use ($props) {
                return array_key_exists($key, $props);
            }, ARRAY_FILTER_USE_KEY)
        );
    }


    /**
     * @return array
     */
    protected function getPropertiesList()
    {
        if (method_exists($this, '__sleep')) {
            return $this->__sleep();
        }
        if (defined('static::PROPERTIES')) {
            return static::PROPERTIES;
        }
        return [];
    }
}

class OrderResponse
{
    use ArrayAwareTrait;

    const PROP_ORDER_ID = 'orderId';
    const PROP_TITLE = 'title';
    const PROP_QUANTITY = 'quantity';
    const PROP_BUYER_USERNAME = 'buyerUsername';
    const PROP_COST_VALUE = 'costValue';
    const PROP_ADDRESS = 'address';

    private $orderId;
    private $title;
    private $quantity;
    private $buyerUsername;
    private $costValue;
    private $address;

    /**
     * @param $orderId
     * @param $title
     * @param $quantity
     * @param $buyerUsername
     * @param $costValue
     * @param $address
     */
    public function __construct(
        $orderId,
        $title,
        $quantity,
        $buyerUsername,
        $costValue,
        $address
    ) {
        $this->orderId = $orderId;
        $this->title = $title;
        $this->quantity = $quantity;
        $this->buyerUsername = $buyerUsername;
        $this->costValue = $costValue;
        $this->address = $address;
    }

    /**
     * @inheritDoc
     */
    public function __sleep()
    {
        return [
            static::PROP_ORDER_ID,
            static::PROP_TITLE,
            static::PROP_QUANTITY,
            static::PROP_BUYER_USERNAME,
            static::PROP_COST_VALUE,
            static::PROP_ADDRESS,
        ];
    }

    /**
     * @return mixed
     */
    public function getOrderId()
    {
        return $this->orderId;
    }

    /**
     * @return mixed
     */
    public function getTitle()
    {
        return $this->title;
    }

    /**
     * @return mixed
     */
    public function getQuantity()
    {
        return $this->quantity;
    }

    /**
     * @return mixed
     */
    public function getBuyerUsername()
    {
        return $this->buyerUsername;
    }

    /**
     * @return mixed
     */
    public function getCostValue()
    {
        return $this->costValue;
    }

    /**
     * @return string
     */
    public function getAddress()
    {
        return $this->address;
    }
}

$orderResponse = new OrderResponse(...);
var_dump($orderResponse->toArray());

我使用这个(需要递归解决适当的关键字):

    /**
     * This method returns the array corresponding to an object, including non public members.
     *
     * If the deep flag is true, is will operate recursively, otherwise (if false) just at the first level.
     *
     * @param object $obj
     * @param bool $deep = true
     * @return array
     * @throws \Exception
     */
    public static function objectToArray(object $obj, bool $deep = true)
    {
        $reflectionClass = new \ReflectionClass(get_class($obj));
        $array = [];
        foreach ($reflectionClass->getProperties() as $property) {
            $property->setAccessible(true);
            $val = $property->getValue($obj);
            if (true === $deep && is_object($val)) {
                $val = self::objectToArray($val);
            }
            $array[$property->getName()] = $val;
            $property->setAccessible(false);
        }
        return $array;
    }

用法示例，代码如下:

class AA{
    public $bb = null;
    protected $one = 11;

}

class BB{
    protected $two = 22;
}


$a = new AA();
$b = new BB();
$a->bb = $b;

var_dump($a)

将打印这个:

array(2) {
  ["bb"] => array(1) {
    ["two"] => int(22)
  }
  ["one"] => int(11)
}

从第一个谷歌点击“PHP对象到assoc数组”，我们有:

function object_to_array($data)
{
    if (is_array($data) || is_object($data))
    {
        $result = [];
        foreach ($data as $key => $value)
        {
            $result[$key] = (is_array($value) || is_object($value)) ? object_to_array($value) : $value;
        }
        return $result;
    }
    return $data;
}

来源是codesnippets.joyent.com。

与json_decode和json_encode的解决方案相比，这个解决方案似乎更快。下面是一个随机的基准测试(使用简单的时间测量):

$obj = (object) [
    'name'    =>'Mike',
    'surname' =>'Jovanson',
    'age'     =>'45',
    'time'    =>1234567890,
    'country' =>'Germany',
];

##### 100 000 cycles ######
* json_decode(json_encode($var))   : 4.15 sec
* object_to_array($var)            : 0.93 sec

我在Laravel Collections中测试了它，这工作得很好。

function objectToArray($data)
{
    if (is_array($data) || is_object($data))
    {
        $result = [];
        foreach ($data as $key => $value)
        {
            $result[$key] = (is_array($data) || is_object($data)) ? objectToArray($value) : $value;
        }
        return $result;
    }
    return $data;
}

这里我创建了一个objectToArray()方法，它也适用于递归对象，比如当$objectA包含$objectB时，$objectB再次指向$objectA。

另外，我使用ReflectionClass将输出限制为公共属性。如果你不需要，就把它扔掉。

    /**
     * Converts given object to array, recursively.
     * Just outputs public properties.
     *
     * @param object|array $object
     * @return array|string
     */
    protected function objectToArray($object) {
        if (in_array($object, $this->usedObjects, TRUE)) {
            return '**recursive**';
        }
        if (is_array($object) || is_object($object)) {
            if (is_object($object)) {
                $this->usedObjects[] = $object;
            }
            $result = array();
            $reflectorClass = new \ReflectionClass(get_class($this));
            foreach ($object as $key => $value) {
                if ($reflectorClass->hasProperty($key) && $reflectorClass->getProperty($key)->isPublic()) {
                    $result[$key] = $this->objectToArray($value);
                }
            }
            return $result;
        }
        return $object;
    }

为了识别已经使用的对象，我在这个(抽象)类中使用了一个受保护的属性，名为$this->usedObjects。如果找到一个递归嵌套对象，它将被字符串**recursive**替换。否则会因为无限循环而失败。

下面是将PHP对象转换为关联数组的递归PHP函数:

// ---------------------------------------------------------
// ----- object_to_array_recursive --- function (PHP) ------
// ---------------------------------------------------------
// --- arg1: -- $object  =  PHP Object         - required --
// --- arg2: -- $assoc   =  TRUE or FALSE      - optional --
// --- arg3: -- $empty   =  '' (Empty String)  - optional --
// ---------------------------------------------------------
// ----- Return: Array from Object --- (associative) -------
// ---------------------------------------------------------

function object_to_array_recursive($object, $assoc=TRUE, $empty='')
{
    $res_arr = array();

    if (!empty($object)) {

        $arrObj = is_object($object) ? get_object_vars($object) : $object;

        $i=0;
        foreach ($arrObj as $key => $val) {
            $akey = ($assoc !== FALSE) ? $key : $i;
            if (is_array($val) || is_object($val)) {
                $res_arr[$akey] = (empty($val)) ? $empty : object_to_array_recursive($val);
            }
            else {
                $res_arr[$akey] = (empty($val)) ? $empty : (string)$val;
            }
            $i++;
        }
    }
    return $res_arr;
}

// ---------------------------------------------------------
// ---------------------------------------------------------

使用的例子:

// ---- Return associative array from object, ... use:
$new_arr1 = object_to_array_recursive($my_object);
// -- or --
// $new_arr1 = object_to_array_recursive($my_object, TRUE);
// -- or --
// $new_arr1 = object_to_array_recursive($my_object, 1);


// ---- Return numeric array from object, ... use:
$new_arr2 = object_to_array_recursive($my_object, FALSE);