PHPのお勉強！

PHP TOP
PHP 8.4.2 Released!

    Exception::__construct

    (PHP 5, PHP 7, PHP 8)

    Exception::__construct — 例外を作成する

    説明

    public Exception::__construct(string $message = "", int $code = 0, ?Throwable $previous = null)

    例外を作成します。

    パラメータ

    message

    スローする例外メッセージ。

    code

    例外コード。

    previous

    以前に使われた例外。例外の連結に使用します。

    注意: Exception クラスのコンストラクタをサブクラス側から呼ぶと、 $code と $message が設定済みの場合はデフォルトの引数を無視します。

    注意

    注意:

    message は、バイナリセーフ ではありません。

    Found A Problem?

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes 2 notes

    up
    45
    talksonweb at gmail dot com
    11 years ago
    For those that haven't done exception chaining. Here's an example.

    This allows you to add the previous exception to the next one and give yourself detailed information in the end as to what happened. This is useful in larger applications.

    <?php
    function theDatabaseObj(){
    if(     database_object ){
    return     database_object;
    }
    else{
    throw new     DatabaseException("Could not connect to the database");
    }
    }

    function     updateProfile( $userInfo ){
    try{
    $db = theDatabaseObj();
    $db->updateProfile();
    }
    catch(     DatabaseException $e ){
    $message = "The user :" . $userInfo->username . " could not update his profile information";
    /* notice the '$e'. I'm adding the previous exception to this exception. I can later get a detailed view of
    where the problem began. Lastly, the number '12' is an exception code. I can use this for categorizing my
    exceptions or don't use it at all. */
    throw new MemberSettingsException($message,12,$e);
    }
    }

    try{
    updateProfile( $userInfo );
    }
    catch(     MemberSettingsException $e ){
    // this will give all information we have collected above.
    echo $e->getTraceAsString();
    }
    ?>
    up
    1
    mattsch at gmail dot com
    11 years ago
    Be aware that while $previous is quite useful in providing exception chaining and better traceability, none of the internal php exceptions (e.g. PDOException, ReflectionException, etc) are called internally within php with $previous in mind.

    So if your code throws an exception, recovers from it, then catches one of these internal php exceptions, recovers from it and throws another exception, you will not know the first exception that was thrown when calling getPrevious.

    See: https://bugs.php.net/bug.php?id=63873
    ＋add a note
    To Top