请问下面if 判断 如何优化？

Question

如何进一步优化下面的if判断，大神帮帮我

private String handlerRepoTradeVariety(BigDecimal days) {
        if (days.compareTo(BigDecimal.valueOf(1d)) == 0) {
            return DataDictionary.PLEDGE_REPO_TRADE_VARIETY_OR001;
        }
        if (days.compareTo(BigDecimal.valueOf(1d)) > 0
                && days.compareTo(BigDecimal.valueOf(7d)) <= 0) {
            return DataDictionary.PLEDGE_REPO_TRADE_VARIETY_OR007;
        }
        if (days.compareTo(BigDecimal.valueOf(7d)) > 0
                && days.compareTo(BigDecimal.valueOf(14d)) <= 0) {
            return DataDictionary.PLEDGE_REPO_TRADE_VARIETY_OR014;
        }
        if (days.compareTo(BigDecimal.valueOf(14d)) > 0
                && days.compareTo(BigDecimal.valueOf(21d)) <= 0) {
            return DataDictionary.PLEDGE_REPO_TRADE_VARIETY_OR021;
        }
        if (days.compareTo(BigDecimal.valueOf(21d)) > 0
                && days.compareTo(BigDecimal.valueOf(30d)) <= 0) {
            return DataDictionary.PLEDGE_REPO_TRADE_VARIETY_OR1M;
        }
        if (days.compareTo(BigDecimal.valueOf(30)) > 0
                && days.compareTo(BigDecimal.valueOf(60)) <= 0) {
            return DataDictionary.PLEDGE_REPO_TRADE_VARIETY_OR2M;
        }
        if (days.compareTo(BigDecimal.valueOf(60)) > 0
                && days.compareTo(BigDecimal.valueOf(90)) <= 0) {
            return DataDictionary.PLEDGE_REPO_TRADE_VARIETY_OR3M;
        }
        return StringUtils.EMPTY;
    }

Answer 1

1、if（）中的判断代码建议封装到独立的方法中，通过合适的命名，便于阅读；
2、考虑使用设计模式优化，比如简单工厂模式