如何用Java格式化日期范围？ [英] How do you format a date range in Java?

问题描述

我有两个日期-开始和结束。我想对它们进行格式化，以便在月份匹配的情况下将其折叠为类似 20-23 AUG的格式，而在月份结束时仍可以正确格式化，例如 20 SEP-1 OCT。

I have two dates - a start and an end. I'd like to format them so that if the months match, they collapse to something like "20-23 AUG" and still format correctly if they break over the end of the month, like "20 SEP - 1 OCT". Are there any libraries out there for accomplishing this, or would I have to hand code rules for displaying ranges of dates using individual DateFormats?

推荐答案

我对其他答案感到失望。 Joda time在GWT中无效，SimpleDateFormat也无效。无论如何，我已经知道GWT中的DateTimeFormat。主要问题是不建议使用日期对象的getMonth（）函数，因此似乎没有比较月和/或年的好方法。此解决方案不包括年份检查（可以通过更改monthFormatter轻松添加），但这对我的情况并不重要。

I was disappointed with the other answers. Joda time didn't work in GWT and neither does SimpleDateFormat. Anyway, I already knew about DateTimeFormat in GWT. The main issue is that date objects getMonth() function is deprecated, and there doesn't seem to be a good way to compare months and/or years. This solution doesn't include year checking (which could be easily added by changing the monthFormatter), but that's not important for my case.

public final class DateUtility
{
    public static final DateTimeFormat MONTH_FORMAT = DateTimeFormat.getFormat("MMM");
    public static final DateTimeFormat DAY_FORMAT = DateTimeFormat.getFormat("dd");
    public static final DateTimeFormat DAY_MONTH_FORMAT = DateTimeFormat.getFormat("dd MMM");

    public static final String DASH = " - ";

    /**
     * Returns a "collapsed" date range String representing the period of time
     * between two Date parameters. Example: August 19 as a {@code startDate}
     * and August 30 as an {@code endDate} will return "19 - 30 AUG", August 28
     * as a {@code startDate} and September 7 as an {@code endDate} will return
     * "28 AUG - 07 SEP". This means if you pass this two dates which cannot
     * collapse into a shorter form, then the longer form is returned.  Years
     * are ignored, and the start and end dates are not checked to ensure we
     * are not going backwards in time (Aug 10 - July 04 is not checked).
     * 
     * @param startDate
     *            the start Date in the range.
     * @param endDate
     *            the end Date in the range.
     * @return a String representation of the range between the two dates given.
     */
    public static String collapseDate(Date startDate, Date endDate) {
        String formattedDateRange;

        // Get a comparison result to determine if the Months are the same
        String startDateMonth = MONTH_FORMAT.format(startDate);
        String endDateMonth = MONTH_FORMAT.format(endDate);

        if (startDateMonth.equals(endDateMonth))
        {
            formattedDateRange = DAY_FORMAT.format(startDate) + DASH
                    + DAY_MONTH_FORMAT.format(endDate).toUpperCase();
        }
        else
        {
            // Months don't match, split the string across both months
            formattedDateRange = DAY_MONTH_FORMAT.format(startDate).toUpperCase()
                    + DASH + DAY_MONTH_FORMAT.format(endDate).toUpperCase();
        }
        return formattedDateRange;
    }
}

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