包含多个if条件的重构代码

如何解决包含多个if条件的重构代码

以下是我为保存UrlEntity编写的一些代码：

public UrlEntity saveUrlEntity(String longUrl,LocalDate dateAdded) {

    int urlLength = longUrl.length();
    if (urlLength >= Constants.MAX_LONG_URL_LENGTH) {
        throw new LongUrlLengthExceededException("URL with length " + urlLength + " exceeds the max length of " + Constants.MAX_LONG_URL_LENGTH + " characters");
    } else {

        List<UrlEntity> urlEntity = urlRepository.findByLongUrl(longUrl);
        if (urlEntity.size() > 0) {
            return urlEntity.get(0);
        } else {
            final String shortUrl = urlShorten.shortenURL(longUrl);
            if (urlRepository.findFirstByShortUrl(shortUrl).isPresent()) {
                logger.error("A short short URL collision occured for long URL: " + longUrl + " with generated short URL" + shortUrl);
                throw new ShortUrlCollisionException("A short URL collision occured");
            } else {
                logger.info("Shortened URL: " + shortUrl);

                final UrlEntity urlEntityToSave = new UrlEntity(dateAdded,longUrl,shortUrl);

                return urlRepository.save(urlEntityToSave);
            }
        }
    }
}

以上代码存在于服务类中，看起来不必要地复杂。我正在尝试进行重构，以使意图很明确。这是我编写的基本重构：

public UrlEntity saveUrlEntity(String longUrl,LocalDate dateAdded) {

    int urlLength = longUrl.length();
    if (urlLength >= Constants.MAX_LONG_URL_LENGTH) {
        throw new LongUrlLengthExceededException("URL with length " + urlLength + " exceeds the max length of " + Constants.MAX_LONG_URL_LENGTH + " characters");
    } else {
        List<UrlEntity> urlEntity = urlRepository.findByLongUrl(longUrl);
        if (urlEntity.size() > 0) {
            return urlEntity.get(0);
        } else {
            return saveUrlEntityValue(longUrl,dateAdded);
        }
    }
}

private UrlEntity saveUrlEntityValue(String longUrl,LocalDate dateAdded){
    final String shortUrl = urlShorten.shortenURL(longUrl);
    if (urlRepository.findFirstByShortUrl(shortUrl).isPresent()) {
        logger.error("A short short URL collision occured for long URL: " + longUrl + " with generated short URL" + shortUrl);
        throw new ShortUrlCollisionException("A short URL collision occured");
    } else {
        logger.info("Shortened URL: " + shortUrl);

        final UrlEntity urlEntityToSave = new UrlEntity(dateAdded,shortUrl);

        return urlRepository.save(urlEntityToSave);
    }
}

此重构不会显着改善代码。是否存在用于重构方法saveUrlEntity的代码模式或惯用方式？我正在使用Java11

解决方法

这是非常主观的，但是...由于您的大多数if语句都是保护/短路子句，它们是throw或return，因此无需使用{ {1}}。我认为这一简单的更改使代码更具可读性。

else

我还建议将public UrlEntity saveUrlEntity(String longUrl,LocalDate dateAdded) { final int urlLength = longUrl.length(); if (urlLength >= Constants.MAX_LONG_URL_LENGTH) { throw new LongUrlLengthExceededException("URL with length " + urlLength + " exceeds the max length of " + Constants.MAX_LONG_URL_LENGTH + " characters"); } final List<UrlEntity> urlEntity = urlRepository.findByLongUrl(longUrl); if (urlEntity.size() > 0) { return urlEntity.get(0); } final String shortUrl = urlShorten.shortenURL(longUrl); if (urlRepository.findFirstByShortUrl(shortUrl).isPresent()) { logger.error("A short short URL collision occured for long URL: " + longUrl + " with generated short URL" + shortUrl); throw new ShortUrlCollisionException("A short URL collision occured"); } logger.info("Shortened URL: " + shortUrl); final UrlEntity urlEntityToSave = new UrlEntity(dateAdded,longUrl,shortUrl); return urlRepository.save(urlEntityToSave); } 替换为urlEntity.size() > 0。

该方法似乎确实在做几件事，这违反了单一责任原则；您可能想考虑将其更好地实现。

,

如果使用throw new或return，则不需要else条件，因为该方法以类似方式结束

public UrlEntity saveUrlEntity(String longUrl,LocalDate dateAdded) {

    int urlLength = longUrl.length();
    if (urlLength >= Constants.MAX_LONG_URL_LENGTH) {
        throw new LongUrlLengthExceededException("URL with length " + urlLength + " exceeds the max length of " + Constants.MAX_LONG_URL_LENGTH + " characters");
    }
    
    List<UrlEntity> urlEntity = urlRepository.findByLongUrl(longUrl);
    if (urlEntity.size() > 0) {
        return urlEntity.get(0);
    }
    
    final String shortUrl = urlShorten.shortenURL(longUrl);
    if (urlRepository.findFirstByShortUrl(shortUrl).isPresent()) {
        logger.error("A short short URL collision occured for long URL: " + longUrl + " with generated short URL" + shortUrl);
        throw new ShortUrlCollisionException("A short URL collision occured");
    }
    
    logger.info("Shortened URL: " + shortUrl);
    final UrlEntity urlEntityToSave = new UrlEntity(dateAdded,shortUrl);
    return urlRepository.save(urlEntityToSave);
}