Java 检查字符串并处理无效日期

当我遇到无效日期时，即2018-02-312018-11-31，我希望我的代码将其转换为该月的最后一天

我不知道如何检查传递的字符串中的值

以下是我目前的代码：

/**
     * If date comes back as invalid, i.e. 2018-11-31
     * convert it to have last day of given month.
     *  
     * @param nextFieldTypeDate
     * @return
     */
    public static LocalDate resolveInvalidDate(String nextFieldTypeDate) {
        LocalDate convertedDate = null;
        try {
            convertedDate = LocalDate.parse(nextFieldTypeDate);
        } catch(DateTimeException dte) {
            //convertedDate = convert date to have last day of the month
            DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM");
            String yearMonthString = nextFieldTypeDate.subSequence(0, 7).toString();
            YearMonth ym = YearMonth.parse(yearMonthString, fmt);
            convertedDate = ym.atEndOfMonth();
        } catch(Exception e) {
            logger.error(e.getMessage());
            throw new ConversionException("Unable to convert nextFieldTypeDate.", e);
        }
        return convertedDate;
    }

---

DatetimeFormatter

的

parseUnresolved

方法在解析时不试图理解解析的值。因此，它接受一个无效的日期，并允许您在尝试对解析的值进行

LocalDate

之前检查这些值

public static LocalDate resolveInvalidDate(String nextFieldTypeDate) {
    ParsePosition position = new ParsePosition(0);
    TemporalAccessor parsed = DateTimeFormatter.ISO_LOCAL_DATE
            .parseUnresolved(nextFieldTypeDate, position);
    if (position.getIndex() < nextFieldTypeDate.length()) {
        throw new IllegalArgumentException("Could not parse entire string");
    }
    YearMonth ym = YearMonth.from(parsed);
    int lastDayOfMonth = ym.lengthOfMonth();
    int parsedDayOfMOnth = parsed.get(ChronoField.DAY_OF_MONTH);
    if (parsedDayOfMOnth > lastDayOfMonth) { // invalid, must be adjusted to lasst day of month
        return ym.atEndOfMonth();
    } else {
        return ym.atDay(parsedDayOfMOnth);
    }
}

输出为：

因此，2月31日无效，已调整为2月28日，2018年是该月的最后一天。2月27日有效，并按原样返回

---

编辑：出于相关目的，人们可能会考虑更简单的

DateTimeFormatter.ISO\u LOCAL\u DATE.withResolverStyle（ResolverStyle.LENIENT）.parse（nextFieldTypeDate，LocalDate:：from）

。然而，这将

2018-02-31

变成

2018-03-03

，我知道这不是您想要的。

不是最干净的解决方案，但这应该可以：

public static LocalDate resolveInvalidDate(String nextFieldTypeDate) {
        LocalDate convertedDate = null;
        try {
            convertedDate = LocalDate.parse(nextFieldTypeDate);
        } catch(DateTimeException dte) {
            //convertedDate = convert date to have last day of the month
            Integer[] constituents = Arrays.stream(nextFieldTypeDate.split("-"))
                                           .map(constituentString -> Integer.valueOf(constituentString))
                                           .toArray(Integer::new);
            LocalDate defaultDate = LocalDate.of(constituents[0], constituents[1], 1);
            LocalDate convertedDate = LocalDate.of(defaultDate.getYear(), defaultDate.getMonth(), defaultDate.lengthOfMonth());
        } catch(Exception e) {
            logger.error(e.getMessage());
            throw new ConversionException("Unable to convert nextFieldTypeDate.", e);
        }
        return convertedDate;
    }

---

当我通过2018-14-25时，它在YearMonth ym=YearMonth.from（解析）上爆炸；是的。你想把14号调成12号吗？你可能想在你的问题中加上这个。不。我将它放在try-catch中，并在无效月份抛出异常

2018-02-28
2018-02-27

public static LocalDate resolveInvalidDate(String nextFieldTypeDate) {
        LocalDate convertedDate = null;
        try {
            convertedDate = LocalDate.parse(nextFieldTypeDate);
        } catch(DateTimeException dte) {
            //convertedDate = convert date to have last day of the month
            Integer[] constituents = Arrays.stream(nextFieldTypeDate.split("-"))
                                           .map(constituentString -> Integer.valueOf(constituentString))
                                           .toArray(Integer::new);
            LocalDate defaultDate = LocalDate.of(constituents[0], constituents[1], 1);
            LocalDate convertedDate = LocalDate.of(defaultDate.getYear(), defaultDate.getMonth(), defaultDate.lengthOfMonth());
        } catch(Exception e) {
            logger.error(e.getMessage());
            throw new ConversionException("Unable to convert nextFieldTypeDate.", e);
        }
        return convertedDate;
    }