PHP自定义异常：如何实现收集数据后的消息延迟格式化？

当前自定义Exception每次添加缺失数据时都会立即更新错误消息，存在不必要的重复计算。要实现仅在调用getMessage()时才动态生成最终错误消息的效果，可通过重写Exception类的getMessage()方法来实现，核心思路是将消息格式化逻辑延迟到方法调用时执行。

优化后的实现代码 #

class MissingAdjustmentDataException extends \Exception
{
    private $missingRedemptionAdjustment = [];
    private $missingPlatformAdjustment = [];

    // 重写getMessage方法，延迟生成错误消息
    public function getMessage(): string
    {
        $messageParts = ['Missing Adjustment data:'];
        
        // 处理RedemptionAdjustment缺失日期
        if (!empty($this->missingRedemptionAdjustment)) {
            $formattedDates = array_map(function(\DateTime $date) {
                return $date->format('Y-m-d');
            }, $this->missingRedemptionAdjustment);
            $messageParts[] = sprintf('RedemptionAdjustment: %s', implode(',', $formattedDates));
        }
        
        // 处理PlatformAdjustment缺失日期（修复原代码循环错误）
        if (!empty($this->missingPlatformAdjustment)) {
            $formattedDates = array_map(function(\DateTime $date) {
                return $date->format('Y-m-d');
            }, $this->missingPlatformAdjustment);
            $messageParts[] = sprintf('PlatformAdjustment: %s', implode(',', $formattedDates));
        }
        
        // 无缺失数据时返回默认提示
        if (count($messageParts) === 1) {
            return 'No missing adjustment data.';
        }
        
        return implode(' ', $messageParts);
    }

    public function inError(): bool
    {
        return !empty($this->missingRedemptionAdjustment) || !empty($this->missingPlatformAdjustment);
    }

    public function addMissingRedemptionAdjustment(\DateTime $dateTime): void
    {
        $this->missingRedemptionAdjustment[] = clone $dateTime;
        // 移除原有的即时更新消息逻辑
    }

    public function addMissingPlatformAdjustment(\DateTime $dateTime): void
    {
        $this->missingPlatformAdjustment[] = clone $dateTime;
        // 移除原有的即时更新消息逻辑
    }
}

关键优化点 #

• 移除了原updateMessage方法，将消息生成逻辑移到重写的getMessage()中，仅在方法被调用时执行格式化
• 修复原代码bug：处理PlatformAdjustment缺失数据时错误循环RedemptionAdjustment数组的问题
• 使用array_map简化日期格式化代码，替代冗余的foreach循环
• add*方法仅负责收集数据，不再触发消息计算，避免重复执行格式化逻辑
• 动态拼接消息内容，无缺失数据时返回友好提示

使用方式（与原逻辑一致） #

$missing = new MissingAdjustmentDataException();        

$testDate = $period->getPreviousPeriod()->getEnd();
$z = 0;
while ($testDate <= $period->getEnd() && $z < 500) {
    if (!in_array($testDate, array_column($activationRedemptionAdjustmentDays, 'effective'))) {
        $missing->addMissingRedemptionAdjustment($testDate);
    }
    if (!in_array($testDate, array_column($platformAdjustmentDays, 'effective'))) {
        $missing->addMissingPlatformAdjustment($testDate);
    }
    $testDate->add(new \DateInterval('P1D'));
    $z++;
}

// 仅当调用getMessage时才生成最终错误消息
if ($missing->inError()) {
    echo $missing->getMessage();
}

内容的提问来源于stack exchange，提问作者jdog