PHP中安全访问嵌套stdClass对象属性的教程

array (size=2)
'raw' =>
object(stdClass)[6]
  public 'actionCodeDescription' => string 'processing.error.203' (length=20)
  public 'params' =>
    object(stdClass)[7]
      public 'respCode_desc' => string 'Transaction rejected' (length=83)

class Order
{
    public $raw;

    function __construct($obj)
    {
        $this->raw = $obj;
    }

    // 用于获取消息的公共方法
    public function getCibMessage()
    {
        $obj = $this->raw; // 简化对原始对象的引用

        // 检查 'params' 属性是否存在，并且 'params' 对象中 'respCode_desc' 属性是否存在
        if (isset($obj->params) && isset($obj->params->respCode_desc)) {
            // 如果存在，则返回 'respCode_desc' 的值
            return $obj->params->respCode_desc;
        } else {
            // 否则，回退到返回 'actionCodeDescription' 的值
            return $obj->actionCodeDescription;
        }
    }

    // 可选：方便调试时输出对象内容
    public function __toString()
    {
        return json_encode($this->raw, JSON_PRETTY_PRINT);
    }
}

<?php

class Order
{
    public $raw;

    function __construct($obj)
    {
        $this->raw = $obj;
    }

    public function getCibMessage()
    {
        $obj = $this->raw;

        if (isset($obj->params) && isset($obj->params->respCode_desc)) {
            return $obj->params->respCode_desc;
        } else {
            return $obj->actionCodeDescription;
        }
    }

    public function __toString()
    {
        return json_encode($this->raw, JSON_PRETTY_PRINT);
    }
}

// 模拟一个包含完整嵌套结构的 stdClass 对象
$dataWithParams = json_decode('{
    "actionCodeDescription": "processing.error.203",
    "params": {
        "respCode_desc": "Transaction rejected by payment gateway"
    }
}');

// 模拟一个缺少 params 或 respCode_desc 的 stdClass 对象
$dataWithoutParams = json_decode('{
    "actionCodeDescription": "processing.success.100"
}');

$dataEmptyParams = json_decode('{
    "actionCodeDescription": "processing.warning.300",
    "params": {}
}');

// 创建 Order 实例并测试
$order1 = new Order($dataWithParams);
echo "Order 1 Message: " . $order1->getCibMessage() . PHP_EOL; // 预期输出: Transaction rejected by payment gateway

$order2 = new Order($dataWithoutParams);
echo "Order 2 Message: " . $order2->getCibMessage() . PHP_EOL; // 预期输出: processing.success.100

$order3 = new Order($dataEmptyParams);
echo "Order 3 Message: " . $order3->getCibMessage() . PHP_EOL; // 预期输出: processing.warning.300

// 打印完整的原始数据（使用 __toString 方法）
echo "\nOrder 1 Raw Data:\n" . $order1 . PHP_EOL;

?>