DateFormat:带点的月份缩写

Question

我有一个日期格式模式: MMM yyyy

并希望:如果月份名称很短,则在名称后面打印一个点.但如果月份名称不短,则不添加任何点.

例:

• 2010年5月应打印:( May 2010无点) - 5月只有3个字母,因此不需要点,因为它不是缩写.
• 2100年12月应打印:( Dec. 2010带点) - 12月长度超过3个字母,因此需要一个点,因为它是缩写.

这是可能的模式,还是我需要通过"手"实现它？

Answer 1

你可以做的是DateFormatSymbols在你的格式化程序中使用一个自定义,在其中你用一个包含"May"而不是"May"的短数字数组覆盖它.

更新:对不起,我得到了最后一点错误,当然它应该是相反的,短暂的月份最初是"Jan","Feb"等,你应该用"Jan.","Feb."替换它们.每个月除了五月.

Answer 2

我已经实现了biziclop 解决方案. - 有用.

如果有人被插入,这里是:

import static org.junit.Assert.assertEquals;

import java.text.DateFormat;
import java.text.DateFormatSymbols;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;

import org.junit.Test;

public class DateFormatTest {

    /** The locale where the tests are for. */
    private static final Locale locale = Locale.ENGLISH;

    /**
     * Add a dot to all abbricated short months.
     *
     * @param dateFormatSymbols
     * @return
     */
    private final DateFormatSymbols addDotToAbbricationMonths(final DateFormatSymbols dateFormatSymbols) {

        String[] shortMonths = dateFormatSymbols.getShortMonths();
        for (int i = 0; i < shortMonths.length; i++) {
            if (dateFormatSymbols.getMonths()[i].length() > shortMonths[i].length()) {
                shortMonths[i] += '.';
            }
        }
        dateFormatSymbols.setShortMonths(shortMonths);

        return dateFormatSymbols;
    }

    /** pattern under test. */
    final DateFormat format = new SimpleDateFormat("MMM yyyy", addDotToAbbricationMonths(new DateFormatSymbols(locale)));

    /** Scenario: May is only 3 letters long, so there is no dot needed, because it is not an abbreviation. */
    @Test
    public void testShortEnought() {
        Date firstMay = new GregorianCalendar(2010, Calendar.MAY, 1).getTime();

        assertEquals("May 2010", format.format(firstMay));
    }

    /** Scenario: December is more than 3 letters long, so there is a dot needed, because it an abbreviation. */
    @Test
    public void testToLong() {
        Date firstDecember = new GregorianCalendar(2010, Calendar.DECEMBER, 1).getTime();

        assertEquals("Dec. 2010", format.format(firstDecember));
    }

    /** Scenario: if the DateFormatSymbols are changed for this special, it should not influence the other formatter. */
    @Test
    public void noInfluence() {
        Date firstDecember = new GregorianCalendar(2010, Calendar.DECEMBER, 1).getTime();

        assertEquals("Dec 2010", new SimpleDateFormat("MMM yyyy", locale).format(firstDecember));
    }
}