格式化日期不含年份
如何创建某个日期的文本表示， 将区域设置考虑在内并且仅包含日期和月份（没有年份）？
以下代码给了我类似23/09/2010的内容
DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault()).format(date); 我想得到23/09
您可以使用正则表达式修剪所有y和之前和之后的任何非字母字符（如果有的话）。 这是一个启动示例：
public static void main(String[] args) throws Exception { for (Locale locale : Locale.getAvailableLocales()) { DateFormat df = getShortDateInstanceWithoutYears(locale); System.out.println(locale + ": " + df.format(new Date())); } } public static DateFormat getShortDateInstanceWithoutYears(Locale locale) { SimpleDateFormat sdf = (SimpleDateFormat) DateFormat.getDateInstance(DateFormat.SHORT, locale); sdf.applyPattern(sdf.toPattern().replaceAll("[^\\p{Alpha}]*y+[^\\p{Alpha}]*", "")); return sdf; }
您会看到此代码段也会针对所有区域设置对其进行测试。 它看起来适用于所有语言环境。
这适用于Android ，以防有人需要它：
int flags = DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_NO_YEAR; String monthAndDayText = DateUtils.formatDateTime(context, date, flags);
只想在模式中提供另一个修改删除年份，这适用于DateFormat.MEDIUM，即使在诸如pt_PT（d’de’MMM’de’yyyy）或lv_LV（y。’gada’d.MMM）之类的语言环境中也是如此。
public static DateFormat getMediumDateInstanceWithoutYears() { SimpleDateFormat sdf = (SimpleDateFormat) DateFormat.getDateInstance(DateFormat.MEDIUM); sdf.applyPattern(sdf.toPattern().replaceAll( "([^\\p{Alpha}']|('[\\p{Alpha}]+'))*y+([^\\p{Alpha}']|('[\\p{Alpha}]+'))*", "")); return sdf; }
我是这样做的：
DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault()); if (dateFormat instanceof SimpleDateFormat) { SimpleDateFormat simpleDateFormat = (SimpleDateFormat) dateFormat; String pattern = simpleDateFormat.toPattern(); // I modified the pattern here so that dd.MM.yyyy would result to dd.MM simpleDateFormat.applyPattern(modifiedPattern); ... etc }
以下是一个实用程序类，它为您提供不带年份的日期格式。 我使用以下代码列出了Java已知的所有日期格式。
Locale[] locales = SimpleDateFormat.getAvailableLocales(); for (int i = 0; i < locales.length; i++) { Locale locale = locales[i]; DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.FULL, locale); }
然后手动删除年份部分。 它返回两种日期格式，正常和缩写，即3月18日星期一对星期一，3月18日。
public class DateFormatWithoutYear { private static Map formats = new HashMap(); private static String DEFAULT_FORMAT = "EEEE, d MMMM"; static { formats.put("_af", "EEEE dd MMMM"); formats.put("_am", "EEEE, d MMMM"); formats.put("_az", "EEEE, d, MMMM"); formats.put("_be", "EEEE, d MMMM"); formats.put("_bg", "dd MMMM, EEEE"); formats.put("BG_bg", "dd MMMM, EEEE"); formats.put("_ca", "EEEE d MMMM"); formats.put("ES_ca", "EEEE d MMMM"); formats.put("_cs", "EEEE, d. MMMM"); formats.put("CZ_cs", "EEEE, d. MMMM"); formats.put("_da", "EEEE 'den' d. MMMM"); formats.put("DK_da", "EEEE 'den' d. MMMM"); formats.put("_de", "EEEE, d. MMMM"); formats.put("AT_de", "EEEE, dd. MMMM"); formats.put("BE_de", "EEEE, d. MMMM"); formats.put("CH_de", "EEEE, d. MMMM"); formats.put("DE_de", "EEEE, d. MMMM"); formats.put("LI_de", "EEEE, d. MMMM"); formats.put("LU_de", "EEEE, d. MMMM"); formats.put("_el", "EEEE, d MMMM"); formats.put("GR_el", "EEEE, d MMMM"); formats.put("_en", "EEEE, MMMM d"); formats.put("AU_en", "EEEE, d MMMM"); formats.put("BE_en", "EEEE d MMMM"); formats.put("BW_en", "EEEE dd MMMM"); formats.put("BZ_en", "EEEE, MMMM d"); formats.put("CA_en", "EEEE, d MMMM"); formats.put("GB_en", "EEEE, d MMMM"); formats.put("HK_en", "EEEE, d MMMM"); formats.put("IE_en", "EEEE d MMMM"); formats.put("IN_en", "EEEE d MMMM"); formats.put("JM_en", "EEEE, MMMM d"); formats.put("MH_en", "EEEE, MMMM d"); formats.put("MT_en", "EEEE, d MMMM"); formats.put("NA_en", "EEEE, MMMM d"); formats.put("NZ_en", "EEEE, d MMMM"); formats.put("PH_en", "EEEE, MMMM d"); formats.put("PK_en", "EEEE, MMMM d"); formats.put("RH_en", "EEEE dd MMMM"); formats.put("SG_en", "EEEE, d MMMM"); formats.put("TT_en", "EEEE, MMMM d"); formats.put("US_en", "EEEE, MMMM d"); formats.put("VI_en", "EEEE, MMMM d"); formats.put("ZA_en", "EEEE dd MMMM"); formats.put("ZW_en", "EEEE dd MMMM"); formats.put("_es", "EEEE d 'de' MMMM"); formats.put("AR_es", "EEEE d 'de' MMMM"); formats.put("BO_es", "EEEE d 'de' MMMM"); formats.put("CL_es", "EEEE d 'de' MMMM"); formats.put("CO_es", "EEEE d 'de' MMMM"); formats.put("CR_es", "EEEE d 'de' MMMM"); formats.put("DO_es", "EEEE d 'de' MMMM"); formats.put("EC_es", "EEEE d 'de' MMMM"); formats.put("ES_es", "EEEE d 'de' MMMM"); formats.put("GT_es", "EEEE d 'de' MMMM"); formats.put("HN_es", "EEEE dd 'de' MMMM"); formats.put("MX_es", "EEEE d 'de' MMMM"); formats.put("NI_es", "EEEE d 'de' MMMM"); formats.put("PA_es", "EEEE d 'de' MMMM"); formats.put("PE_es", "EEEE d 'de' MMMM"); formats.put("PR_es", "EEEE d 'de' MMMM"); formats.put("PY_es", "EEEE d 'de' MMMM"); formats.put("SV_es", "EEEE d 'de' MMMM"); formats.put("US_es", "EEEE d 'de' MMMM"); formats.put("UY_es", "EEEE d 'de' MMMM"); formats.put("VE_es", "EEEE d 'de' MMMM"); formats.put("_et", "EEEE, d. MMMM"); formats.put("_eu", "EEEE, MMMM'ren' dd'a'"); formats.put("_fi", "cccc, d. MMMM"); formats.put("FI_fi", "cccc, d. MMMM"); formats.put("_fil", "EEEE, MMMM dd"); formats.put("PH_fil", "EEEE, MMMM dd"); formats.put("_fr", "EEEE d MMMM"); formats.put("BE_fr", "EEEE d MMMM"); formats.put("CA_fr", "EEEE d MMMM"); formats.put("CH_fr", "EEEE, d MMMM"); formats.put("FR_fr", "EEEE d MMMM"); formats.put("LU_fr", "EEEE d MMMM"); formats.put("MC_fr", "EEEE d MMMM"); formats.put("_gl", "EEEE dd MMMM"); formats.put("_iw", "EEEE, d בMMMM"); formats.put("IL_iw", "EEEE, d בMMMM"); formats.put("_hi", "EEEE, d MMMM"); formats.put("IN_hi", "EEEE, d MMMM"); formats.put("_hr", "EEEE, d. MMMM"); formats.put("HR_hr", "EEEE, d. MMMM"); formats.put("_hu", "MMMM d., EEEE"); formats.put("HU_hu", "MMMM d., EEEE"); formats.put("_hy", "EEEE, MMMM d"); formats.put("_in", "EEEE, dd MMMM"); formats.put("ID_in", "EEEE, dd MMMM"); formats.put("_it", "EEEE d MMMM"); formats.put("CH_it", "EEEE, d MMMM"); formats.put("IT_it", "EEEE d MMMM"); formats.put("_ja", "M月d日EEEE"); formats.put("JP_ja", "M月d日EEEE"); formats.put("_ka", "EEEE, MMMM dd"); formats.put("_kk", "EEEE, d MMMM"); formats.put("_ko", "M월 d일 EEEE"); formats.put("KR_ko", "M월 d일 EEEE"); formats.put("_lt", "'m'. MMMM d 'd'., EEEE"); formats.put("LT_lt", "'m'. MMMM d 'd'., EEEE"); formats.put("_lv", "EEEE, d. MMMM"); formats.put("LV_lv", "EEEE, d. MMMM"); formats.put("_mk", "EEEE, dd MMMM"); formats.put("_ms", "EEEE, d MMMM"); formats.put("_nb", "EEEE d. MMMM"); formats.put("NO_nb", "EEEE d. MMMM"); formats.put("_nl", "EEEE d MMMM"); formats.put("BE_nl", "EEEE d MMMM"); formats.put("NL_nl", "EEEE d MMMM"); formats.put("_pl", "EEEE, d MMMM"); formats.put("PL_pl", "EEEE, d MMMM"); formats.put("_ps", "EEEE د MMMM d"); formats.put("_pt", "EEEE, d 'de' MMMM"); formats.put("BR_pt", "EEEE, d 'de' MMMM"); formats.put("PT_pt", "EEEE, d 'de' MMMM"); formats.put("_rm", "EEEE, d. MMMM"); formats.put("_ro", "EEEE, d MMMM"); formats.put("RO_ro", "EEEE, d MMMM"); formats.put("_ru", "EEEE, d MMMM"); formats.put("RU_ru", "EEEE, d MMMM"); formats.put("UA_ru", "EEEE, d MMMM"); formats.put("_sk", "EEEE, d. MMMM"); formats.put("SK_sk", "EEEE, d. MMMM"); formats.put("_sl", "EEEE, dd. MMMM"); formats.put("SI_sl", "EEEE, dd. MMMM"); formats.put("_sr", "EEEE, dd. MMMM"); formats.put("BA_sr", "EEEE, dd. MMMM"); formats.put("CS_sr", "EEEE, dd. MMMM"); formats.put("CYRL_sr", "EEEE, dd. MMMM"); formats.put("CYRL_sr", "EEEE, dd. MMMM"); formats.put("CYRL_sr", "EEEE, dd. MMMM"); formats.put("CYRL_sr", "EEEE, dd. MMMM"); formats.put("CYRL_sr", "EEEE, dd. MMMM"); formats.put("CYRL_sr", "EEEE, dd. MMMM"); formats.put("LATN_sr", "EEEE, dd. MMMM"); formats.put("LATN_sr", "EEEE, dd. MMMM"); formats.put("LATN_sr", "EEEE, dd. MMMM"); formats.put("LATN_sr", "EEEE, dd. MMMM"); formats.put("LATN_sr", "EEEE, dd. MMMM"); formats.put("LATN_sr", "EEEE, dd. MMMM"); formats.put("ME_sr", "EEEE, dd. MMMM"); formats.put("RS_sr", "EEEE, dd. MMMM"); formats.put("YU_sr", "EEEE, dd. MMMM"); formats.put("_sv", "EEEE'en' 'den' d:'e' MMMM"); formats.put("FI_sv", "EEEE'en' 'den' d:'e' MMMM"); formats.put("SE_sv", "EEEE'en' 'den' d:'e' MMMM"); formats.put("_sw", "EEEE, d MMMM"); formats.put("_th", "EEEEที่ d MMMM G"); formats.put("TH_th", "EEEEที่ d MMMM G"); formats.put("_tr", "d MMMM EEEE"); formats.put("TR_tr", "d MMMM EEEE"); formats.put("_uk", "EEEE, d MMMM"); formats.put("UA_uk", "EEEE, d MMMM"); formats.put("_uz", "EEEE, MMMM dd"); formats.put("_vi", "EEEE, 'ngày' dd MMMM"); formats.put("VN_vi", "EEEE, 'ngày' dd MMMM"); formats.put("_zh", "M月d日EEEE"); formats.put("CN_zh", "M月d日EEEE"); formats.put("HK_zh", "M月d日EEEE"); formats.put("HANS_zh", "M月d日EEEE"); formats.put("HANS_zh", "M月d日EEEE"); formats.put("HANS_zh", "M月d日EEEE"); formats.put("HANS_zh", "M月d日EEEE"); formats.put("HANT_zh", "M月d日EEEE"); formats.put("HANT_zh", "M月d日EEEE"); formats.put("HANT_zh", "MM月dd日EEEE"); formats.put("HANT_zh", "M月d日EEEE"); formats.put("MO_zh", "MM月dd日EEEE"); formats.put("SG_zh", "M月d日EEEE"); formats.put("TW_zh", "M月d日EEEE"); formats.put("_zu", "EEEE dd MMMM"); } public static String getLongFormatWithoutYear(Locale locale) { if (locale != null) { String key = locale.getCountry() + "_" + locale.getLanguage(); String format = formats.get(key); if (format != null) { return format; } } return DEFAULT_FORMAT; } public static String getShortFormatWithoutYear(Locale locale) { String longFormat = getLongFormatWithoutYear(locale); return longFormat.replaceAll("E+", "E").replaceAll("MMMM", "MMM"); } }
这里的主要困难是在某些语言环境中，月份和日期的顺序是不同的。 我解决它的方式与此处提供的方式不同，并希望它适用于所有情况。
Date dateObject = ...; String dayMonthDateString = getDayMonthDateString(dateObject, Locale.GERMANY); Log.i("customDate", "dayMonthDateString = " + dayMonthDateString); private String getDayMonthDateString(Date date, Locale locale) { try { boolean dayBeforeMonth = defineDayMonthOrder(locale); SimpleDateFormat newDateFormat; if (dayBeforeMonth) { newDateFormat = new SimpleDateFormat("dd/MM", locale); } else { newDateFormat = new SimpleDateFormat("MM/dd", locale); } return newDateFormat.format(date); } catch (ParseException e) { e.printStackTrace(); } return null; } private boolean defineDayMonthOrder(Locale locale) throws ParseException { String day = "10"; String month = "11"; String year = "12"; String calendarDate = day + "." + month + "." + year; SimpleDateFormat format = new SimpleDateFormat("dd.MM.yy"); Date date = format.parse(calendarDate); String localizedDate = SimpleDateFormat.getDateInstance(SimpleDateFormat.SHORT, locale).format(date); int indexOfDay = localizedDate.indexOf(day); int indexOfMonth = localizedDate.indexOf(month); return indexOfDay < indexOfMonth; }
使用com.ibm.icu库：
import com.ibm.icu.text.DateFormat; DateFormat.getPatternInstance(DateFormat.MONTH_DAY, locale).format(date);
如果您使用Android，您可能可以使用getBestDateTimePattern ，并将所有要允许的字段放在那里。 它应该根据当前语言环境自动输入正确的顺序和特殊字符。
可悲的是，它需要API 18+。
编辑：遗憾的是，这似乎是一个不太好的选择。 我在这里写过： http ： //code.google.com/p/android/issues/detail？id = 171591
所以，这就是我所做的：
public static String convertDateToString(Context context, Locale locale, final Date date, boolean alsoShowYearIfPossible) { if (date == null) return ""; String defaultDateFormat; if (locale != null) { defaultDateFormat = ((SimpleDateFormat) DateFormat.getDateInstance(DateFormat.SHORT, locale)).toLocalizedPattern(); } else defaultDateFormat = getDefaultDateFormat(context); if (alsoShowYearIfPossible) return new SimpleDateFormat(defaultDateFormat, Locale.getDefault()).format(date); //need removal of year String removedYearFormat = defaultDateFormat.replaceAll("[^{mdMD}]*y+[^{mdMD}]*", ""); String result = new SimpleDateFormat(removedYearFormat, Locale.getDefault()).format(date); //Log.d("AppLog", locale + ": \"" + defaultDateFormat + "\" => \"" + removedYearFormat + "\" =>" + result); return result; } private static String getDefaultDateFormat(final Context context) { String dateFormatString = Settings.System.getString(context.getContentResolver(), Settings.System.DATE_FORMAT); if (TextUtils.isEmpty(dateFormatString)) { // if device date format is available , use device date order,and if not available ,use default final char[] dateFormatOrder = android.text.format.DateFormat.getDateFormatOrder(context); if (dateFormatOrder.length == 0) dateFormatString = DEFAULT_DATE_FORMAT; else { // construct the date format based on the device date order final StringBuilder sb = new StringBuilder(); for (int i = 0; i < dateFormatOrder.length; ++i) { final char c = dateFormatOrder[i]; switch (Character.toLowerCase(c)) { case 'y': sb.append("yyyy"); break; case 'm': sb.append("MM"); break; case 'd': sb.append("dd"); break; } if (i != dateFormatOrder.length - 1) sb.append('-'); } dateFormatString = sb.toString(); } } return dateFormatString; }
此代码适用于Android 5.0.2上可用的任何区域设置。
以下是如何在语言环境中检查它的示例：
Date date = new Date(); for (Locale locale : Locale.getAvailableLocales()) { SimpleDateFormat sdf = (SimpleDateFormat) DateFormat.getDateInstance(DateFormat.SHORT, locale); String localizedDatePattern = sdf.toLocalizedPattern(); convertDateToString(this,locale,date,false); }
尽管Andrzej Pronobis的答案非常好，但是对于ZH local来说它并不起作用。 我最终手动从本地化模式中删除了一年。 此function针对SHORT，MEDIUM，LONG和FULL格式的所有本地人进行了测试。
public String removeYearFromPattern(String pattern) throws SCException { int yPos = 0; while (yPos < pattern.length() && pattern.charAt(yPos) != 'y' && pattern.charAt(yPos) != 'Y') { if (pattern.charAt(yPos) == '\'') { yPos++; while (yPos < pattern.length() && pattern.charAt(yPos) != '\'') yPos++; } yPos++; } if (yPos >= pattern.length()) throw new IllegalArgumentException("Did not find year in pattern"); String validPatternLetters = "EMd"; // go forward int endPos = yPos; while (endPos < pattern.length() && validPatternLetters.indexOf(pattern.charAt(endPos)) == -1) { endPos++; if (endPos < pattern.length() && pattern.charAt(endPos) == '\'') { endPos++; while (endPos < pattern.length() && pattern.charAt(endPos) != '\'') endPos++; } } if (endPos != pattern.length()) validPatternLetters += ','; // go backward int startPos = yPos; while (startPos >= 0 && validPatternLetters.indexOf(pattern.charAt(startPos)) == -1) { startPos--; if (startPos >= 0 && pattern.charAt(startPos) == '\'') { startPos--; while (startPos >= 0 && pattern.charAt(startPos) != '\'') startPos--; } } startPos++; String yLetters = pattern.substring(startPos, endPos); return pattern.replace(yLetters, " ").trim(); }
可以使用此代码测试此function
for (Locale locale : Locale.getAvailableLocales()) { SimpleDateFormat df = (SimpleDateFormat) DateFormat.getDateInstance(DateFormat.FULL, locale); String dfPattern = "?"; String newPattern = "?"; try { dfPattern = df.toPattern(); newPattern = removeYearFromPattern(dfPattern); df.applyPattern(newPattern); } catch (IllegalArgumentException e) { Log.e(TAG, "Error removing year for " + locale + ": " + e.getMessage()); } Log.d(TAG, locale + ": old " + dfPattern + "; new " + newPattern + "; result " + df.format(new Date())); }
我知道它不像正则表达式那么优雅，但它更快一点，适用于所有当地人（如果我能够识别）。
要么
SimpleDateFormat dateFormat = new SimpleDateFormat("EEE MMM d'); dateFormat.format(date);