包含多个if条件的java重构代码

s1ag04yj 于 2021-07-05 发布在 Java

关注(0)|答案(2)|浏览(311)

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);
            }
        }
    }
}

上面的代码存在于服务类中，看起来非常复杂。我正在尝试重构，以使意图明确。这是我写的一个基本重构：

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, longUrl, shortUrl);

        return urlRepository.save(urlEntityToSave);
    }
}

这种重构并没有实质性地改进代码。有没有代码模式或惯用的方法来重构方法 saveUrlEntity ? 我在用 Java11

Java spring spring-boot design-patterns refactoring

来源：https://stackoverflow.com/questions/63729967/refactoring-code-that-contains-multiple-if-conditions

2条答案

按热度按时间

fwzugrvs1#

这很主观，但是。。。因为你大部分时间 if 语句是保护/短路子句 throw 或者 return ，无需使用 else . 我认为这个简单的改变使代码更具可读性。

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);
}

我也建议更换 urlEntity.size() > 0 与 !urlEntity.isEmpty() .
这种方法似乎确实在做几件事，这违反了单一责任原则；你也许应该好好考虑一下。

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xhv8bpkk2#

如果你使用 throw new 或者 return 您不需要else条件，因为方法的结尾是

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, longUrl, shortUrl);
    return urlRepository.save(urlEntityToSave);
}

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包含多个if条件的java重构代码

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