问题
I know this will give me the day of the month as a number (11, 21, 23):
SimpleDateFormat formatDayOfMonth = new SimpleDateFormat(\"d\");
But how do you format the day of the month to include an ordinal indicator, say 11th, 21st or 23rd?
回答1:
// https://github.com/google/guava
import static com.google.common.base.Preconditions.*;
String getDayOfMonthSuffix(final int n) {
checkArgument(n >= 1 && n <= 31, "illegal day of month: " + n);
if (n >= 11 && n <= 13) {
return "th";
}
switch (n % 10) {
case 1: return "st";
case 2: return "nd";
case 3: return "rd";
default: return "th";
}
}
The table from @kaliatech is nice, but since the same information is repeated, it opens the chance for a bug. Such a bug actually exists in the table for 7tn, 17tn, and 27tn (this bug might get fixed as time goes on because of the fluid nature of StackOverflow, so check the version history on the answer to see the error).
回答2:
There is nothing in JDK to do this.
static String[] suffixes =
// 0 1 2 3 4 5 6 7 8 9
{ "th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th",
// 10 11 12 13 14 15 16 17 18 19
"th", "th", "th", "th", "th", "th", "th", "th", "th", "th",
// 20 21 22 23 24 25 26 27 28 29
"th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th",
// 30 31
"th", "st" };
Date date = new Date();
SimpleDateFormat formatDayOfMonth = new SimpleDateFormat("d");
int day = Integer.parseInt(formatDateOfMonth.format(date));
String dayStr = day + suffixes[day];
Or using Calendar:
Calendar c = Calendar.getInstance();
c.setTime(date);
int day = c.get(Calendar.DAY_OF_MONTH);
String dayStr = day + suffixes[day];
Per comments by @thorbjørn-ravn-andersen, a table like this can be helpful when localizing:
static String[] suffixes =
{ "0th", "1st", "2nd", "3rd", "4th", "5th", "6th", "7th", "8th", "9th",
"10th", "11th", "12th", "13th", "14th", "15th", "16th", "17th", "18th", "19th",
"20th", "21st", "22nd", "23rd", "24th", "25th", "26th", "27th", "28th", "29th",
"30th", "31st" };
回答3:
private String getCurrentDateInSpecificFormat(Calendar currentCalDate) {
String dayNumberSuffix = getDayNumberSuffix(currentCalDate.get(Calendar.DAY_OF_MONTH));
DateFormat dateFormat = new SimpleDateFormat(" d'" + dayNumberSuffix + "' MMMM yyyy");
return dateFormat.format(currentCalDate.getTime());
}
private String getDayNumberSuffix(int day) {
if (day >= 11 && day <= 13) {
return "th";
}
switch (day % 10) {
case 1:
return "st";
case 2:
return "nd";
case 3:
return "rd";
default:
return "th";
}
}
回答4:
Question is little old. As this question is very noisy so posting what I did solved with static method as a util. Just copy, paste and use it!
public static String getFormattedDate(Date date){
Calendar cal=Calendar.getInstance();
cal.setTime(date);
//2nd of march 2015
int day=cal.get(Calendar.DATE);
if(!((day>10) && (day<19)))
switch (day % 10) {
case 1:
return new SimpleDateFormat("d'st' 'of' MMMM yyyy").format(date);
case 2:
return new SimpleDateFormat("d'nd' 'of' MMMM yyyy").format(date);
case 3:
return new SimpleDateFormat("d'rd' 'of' MMMM yyyy").format(date);
default:
return new SimpleDateFormat("d'th' 'of' MMMM yyyy").format(date);
}
return new SimpleDateFormat("d'th' 'of' MMMM yyyy").format(date);
}
For testing purose
Example: calling it from main method!
Date date = new Date();
Calendar cal=Calendar.getInstance();
cal.setTime(date);
for(int i=0;i<32;i++){
System.out.println(getFormattedDate(cal.getTime()));
cal.set(Calendar.DATE,(cal.getTime().getDate()+1));
}
Output:
22nd of February 2018
23rd of February 2018
24th of February 2018
25th of February 2018
26th of February 2018
27th of February 2018
28th of February 2018
1st of March 2018
2nd of March 2018
3rd of March 2018
4th of March 2018
5th of March 2018
6th of March 2018
7th of March 2018
8th of March 2018
9th of March 2018
10th of March 2018
11th of March 2018
12th of March 2018
13th of March 2018
14th of March 2018
15th of March 2018
16th of March 2018
17th of March 2018
18th of March 2018
19th of March 2018
20th of March 2018
21st of March 2018
22nd of March 2018
23rd of March 2018
24th of March 2018
25th of March 2018
回答5:
String ordinal(int num)
{
String[] suffix = {"th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th"};
int m = num % 100;
return String.valueOf(num) + suffix[(m > 3 && m < 21) ? 0 : (m % 10)];
}
回答6:
I should like to contribute the modern answer. The SimpleDateFormat class was OK to use when the question was asked 8 years ago, but you should avoid it now as it is not only long outdated, but also notoriously troublesome. Use java.time instead.
Edit
DateTimeFormatterBuilder.appendText(TemporalField, Map<Long, String>) is great for this purpose. Using it we build a formatter that does the work for us:
Map<Long, String> ordinalNumbers = new HashMap<>(42);
ordinalNumbers.put(1L, "1st");
ordinalNumbers.put(2L, "2nd");
ordinalNumbers.put(3L, "3rd");
ordinalNumbers.put(21L, "21st");
ordinalNumbers.put(22L, "22nd");
ordinalNumbers.put(23L, "23rd");
ordinalNumbers.put(31L, "31st");
for (long d = 1; d <= 31; d++) {
ordinalNumbers.putIfAbsent(d, "" + d + "th");
}
DateTimeFormatter dayOfMonthFormatter = new DateTimeFormatterBuilder()
.appendText(ChronoField.DAY_OF_MONTH, ordinalNumbers)
.appendPattern(" MMMM")
.toFormatter();
LocalDate date = LocalDate.of(2018, Month.AUGUST, 30);
for (int i = 0; i < 6; i++) {
System.out.println(date.format(dayOfMonthFormatter));
date = date.plusDays(1);
}
The output from this snippet is:
30th August 31st August 1st September 2nd September 3rd September 4th September
Old answer
This code is shorter, but IMHO not so elegant.
// ordinal indicators by numbers (1-based, cell 0 is wasted)
String[] ordinalIndicators = new String[31 + 1];
Arrays.fill(ordinalIndicators, 1, ordinalIndicators.length, "th");
ordinalIndicators[1] = ordinalIndicators[21] = ordinalIndicators[31] = "st";
ordinalIndicators[2] = ordinalIndicators[22] = "nd";
ordinalIndicators[3] = ordinalIndicators[23] = "rd";
DateTimeFormatter dayOfMonthFormatter = DateTimeFormatter.ofPattern("d");
LocalDate today = LocalDate.now(ZoneId.of("America/Menominee")).plusWeeks(1);
System.out.println(today.format(dayOfMonthFormatter)
+ ordinalIndicators[today.getDayOfMonth()]);
Running this snippet just now I got
23rd
One of the many features of java.time is that it’s straightforward and reliable to get the day of month as an int, which is obviously needed for picking the right suffix from the table.
I recommend you write a unit test too.
PS A similar formatter can also be used for parsing a date string containing ordinal numbers like 1st, 2nd, etc. That was done in this question: Java - Parse date with optional seconds.
Link: Oracle tutorial: Date Time explaining how to use java.time.
回答7:
If you try to be aware of i18n the solution get even more complicated.
The problem is that in other languages the suffix may depend not only on the number itself, but also on the noun it counts. For example in Russian it would be "2-ой день", but "2-ая неделя" (these mean "2nd day", but "2nd week"). This is not apply if we formatting only days, but in a bit more generic case you should be aware of complexity.
I think nice solution (I didn't have time to actually implement) would be to extend SimpleDateFormetter to apply Locale-aware MessageFormat before passing to the parent class. This way you would be able to support let say for March formats %M to get "3-rd", %MM to get "03-rd" and %MMM to get "third". From outside this class looks like regular SimpleDateFormatter, but supports more formats. Also if this pattern would be by mistake applied by regular SimpleDateFormetter the result would be incorrectly formatted, but still readable.
回答8:
Many of the examples here will not work for 11, 12, 13. This is more generic and will work for all case.
switch (date) {
case 1:
case 21:
case 31:
return "" + date + "st";
case 2:
case 22:
return "" + date + "nd";
case 3:
case 23:
return "" + date + "rd";
default:
return "" + date + "th";
}
回答9:
I can't be satisfied by the answers calling for a English-only solution based on manual formats. I've been looking for a proper solution for a while now and I finally found it.
You should be using RuleBasedNumberFormat. It works perfectly and it's respectful of the Locale.
回答10:
There is a simpler and sure way of doing this. The function you'll need to use is getDateFromDateString(dateString); It basically removes the st/nd/rd/th off of a date string and simply parses it. You can change your SimpleDateFormat to anything and this will work.
public static final SimpleDateFormat sdf = new SimpleDateFormat("d");
public static final Pattern p = Pattern.compile("([0-9]+)(st|nd|rd|th)");
private static Date getDateFromDateString(String dateString) throws ParseException {
return sdf.parse(deleteOrdinal(dateString));
}
private static String deleteOrdinal(String dateString) {
Matcher m = p.matcher(dateString);
while (m.find()) {
dateString = dateString.replaceAll(Matcher.quoteReplacement(m.group(0)), m.group(1));
}
return dateString;
}
回答11:
Only issue with the solution provided by Greg is that it does not account for number greater than 100 with the "teen" numbers ending. For example, 111 should be 111th, not 111st. This is my solution:
/**
* Return ordinal suffix (e.g. 'st', 'nd', 'rd', or 'th') for a given number
*
* @param value
* a number
* @return Ordinal suffix for the given number
*/
public static String getOrdinalSuffix( int value )
{
int hunRem = value % 100;
int tenRem = value % 10;
if ( hunRem - tenRem == 10 )
{
return "th";
}
switch ( tenRem )
{
case 1:
return "st";
case 2:
return "nd";
case 3:
return "rd";
default:
return "th";
}
}
回答12:
Here is an approach that updates a DateTimeFormatter pattern with the correct suffix literal if it finds the pattern d'00', e.g. for day of month 1 it would be replaced with d'st'. Once the pattern has been updated it can then just be fed into the DateTimeFormatter to do the rest.
private static String[] suffixes = {"th", "st", "nd", "rd"};
private static String updatePatternWithDayOfMonthSuffix(TemporalAccessor temporal, String pattern) {
String newPattern = pattern;
// Check for pattern `d'00'`.
if (pattern.matches(".*[d]'00'.*")) {
int dayOfMonth = temporal.get(ChronoField.DAY_OF_MONTH);
int relevantDigits = dayOfMonth < 30 ? dayOfMonth % 20 : dayOfMonth % 30;
String suffix = suffixes[relevantDigits <= 3 ? relevantDigits : 0];
newPattern = pattern.replaceAll("[d]'00'", "d'" + suffix + "'");
}
return newPattern;
}
It does require that the original pattern is updated just prior to every formatting call, e.g.
public static String format(TemporalAccessor temporal, String pattern) {
DateTimeFormatter formatter = DateTimeFormatter.ofPattern(updatePatternWithDayOfMonthSuffix(temporal, pattern));
return formatter.format(temporal);
}
So this is useful if the formatting pattern is defined outside of Java code, e.g. a template, where as if you can define the pattern in Java then the answer by @OleV.V. might be more appropriate
回答13:
I wrote my self a helper method to get patterns for this.
public static String getPattern(int month) {
String first = "MMMM dd";
String last = ", yyyy";
String pos = (month == 1 || month == 21 || month == 31) ? "'st'" : (month == 2 || month == 22) ? "'nd'" : (month == 3 || month == 23) ? "'rd'" : "'th'";
return first + pos + last;
}
and then we can call it as
LocalDate localDate = LocalDate.now();//For reference
int month = localDate.getDayOfMonth();
DateTimeFormatter formatter = DateTimeFormatter.ofPattern(getPattern(month));
String date = localDate.format(formatter);
System.out.println(date);
the output is
December 12th, 2018
回答14:
In kotlin you can use like this
fun changeDateFormats(currentFormat: String, dateString: String): String {
var result = ""
try {
val formatterOld = SimpleDateFormat(currentFormat, Locale.getDefault())
formatterOld.timeZone = TimeZone.getTimeZone("UTC")
var date: Date? = null
date = formatterOld.parse(dateString)
val dayFormate = SimpleDateFormat("d", Locale.getDefault())
var day = dayFormate.format(date)
val formatterNew = SimpleDateFormat("hh:mm a, d'" + getDayOfMonthSuffix(day.toInt()) + "' MMM yy", Locale.getDefault())
if (date != null) {
result = formatterNew.format(date)
}
} catch (e: ParseException) {
e.printStackTrace()
return dateString
}
return result
}
private fun getDayOfMonthSuffix(n: Int): String {
if (n in 11..13) {
return "th"
}
when (n % 10) {
1 -> return "st"
2 -> return "nd"
3 -> return "rd"
else -> return "th"
}
}
set like this
txt_chat_time_me.text = changeDateFormats("SERVER_DATE", "DATE")
回答15:
If you need this on Android you can check out this answer
It's internationalized solution, though. And you don't need to reinvent the bicycle ;)
回答16:
The following method can be used to get the formatted string of the date which is passed in to it. It'll format the date to say 1st,2nd,3rd,4th .. using SimpleDateFormat in Java. eg:- 1st of September 2015
public String getFormattedDate(Date date){
Calendar cal=Calendar.getInstance();
cal.setTime(date);
//2nd of march 2015
int day=cal.get(Calendar.DATE);
switch (day % 10) {
case 1:
return new SimpleDateFormat("d'st' 'of' MMMM yyyy").format(date);
case 2:
return new SimpleDateFormat("d'nd' 'of' MMMM yyyy").format(date);
case 3:
return new SimpleDateFormat("d'rd' 'of' MMMM yyyy").format(date);
default:
return new SimpleDateFormat("d'th' 'of' MMMM yyyy").format(date);
}
回答17:
The following is a more efficient answer to the question rather than hard-coding the style.
To change the day to ordinal number you need to use the following suffix.
DD + TH = DDTH result >>>> 4TH
OR to spell the number add SP to the format
DD + SPTH = DDSPTH result >>> FOURTH
Find my completed answer in this question.
回答18:
public String getDaySuffix(int inDay)
{
String s = String.valueOf(inDay);
if (s.endsWith("1"))
{
return "st";
}
else if (s.endsWith("2"))
{
return "nd";
}
else if (s.endsWith("3"))
{
return "rd";
}
else
{
return "th";
}
}
来源：https://stackoverflow.com/questions/4011075/how-do-you-format-the-day-of-the-month-to-say-11th-21st-or-23rd-ordinal