java.util.Date format conversion yyyy-mm-dd to mm-dd-yyyy

Question

I have a java.util.Date in the format yyyy-mm-dd . I want it to be in the format mm-dd-yyyy

Below is the sample util I tried out for this conversion:

// Setting the pattern
SimpleDateFormat sm = new SimpleDateFormat("mm-dd-yyyy");
// myDate is the java.util.Date in yyyy-mm-dd format
// Converting it into String using formatter
String strDate = sm.format(myDate);
//Converting the String back to java.util.Date
Date dt = sm.parse(strDate);

Still the output I am getting is not in the format mm-dd-yyyy .

Kindly let me know how to format a java.util.Date from yyyy-mm-dd to mm-dd-yyyy

Answer 1

Date is a container for the number of milliseconds since the Unix epoch ( 00:00:00 UTC on 1 January 1970).

It has no concept of format.

Java 8+

LocalDateTime ldt = LocalDateTime.now();
System.out.println(DateTimeFormatter.ofPattern("MM-dd-yyyy", Locale.ENGLISH).format(ldt));
System.out.println(DateTimeFormatter.ofPattern("yyyy-MM-dd", Locale.ENGLISH).format(ldt));
System.out.println(ldt);

Outputs...

05-11-2018
2018-05-11
2018-05-11T17:24:42.980

Java 7-

You should be making use of the ThreeTen Backport

Original Answer

For example...

Date myDate = new Date();
System.out.println(myDate);
System.out.println(new SimpleDateFormat("MM-dd-yyyy").format(myDate));
System.out.println(new SimpleDateFormat("yyyy-MM-dd").format(myDate));
System.out.println(myDate);

Outputs...

Wed Aug 28 16:20:39 EST 2013
08-28-2013
2013-08-28
Wed Aug 28 16:20:39 EST 2013

None of the formatting has changed the underlying Date value. This is the purpose of the DateFormatter s

Updated with additional example

Just in case the first example didn't make sense...

This example uses two formatters to format the same date. I then use these same formatters to parse the String values back to Date s. The resulting parse does not alter the way Date reports it's value.

Date#toString is just a dump of it's contents. You can't change this, but you can format the Date object any way you like

try {
    Date myDate = new Date();
    System.out.println(myDate);

    SimpleDateFormat mdyFormat = new SimpleDateFormat("MM-dd-yyyy");
    SimpleDateFormat dmyFormat = new SimpleDateFormat("yyyy-MM-dd");

    // Format the date to Strings
    String mdy = mdyFormat.format(myDate);
    String dmy = dmyFormat.format(myDate);

    // Results...
    System.out.println(mdy);
    System.out.println(dmy);
    // Parse the Strings back to dates
    // Note, the formats don't "stick" with the Date value
    System.out.println(mdyFormat.parse(mdy));
    System.out.println(dmyFormat.parse(dmy));
} catch (ParseException exp) {
    exp.printStackTrace();
}

Which outputs...

Wed Aug 28 16:24:54 EST 2013
08-28-2013
2013-08-28
Wed Aug 28 00:00:00 EST 2013
Wed Aug 28 00:00:00 EST 2013

Also, be careful of the format patterns. Take a closer look at SimpleDateFormat to make sure you're not using the wrong patterns ;)

Answer 2

SimpleDateFormat("MM-dd-yyyy");

instead of

SimpleDateFormat("mm-dd-yyyy");

because MM points Month , mm points minutes

SimpleDateFormat sm = new SimpleDateFormat("MM-dd-yyyy");
String strDate = sm.format(myDate);

Answer 3

'M' (Capital) represent month & 'm' (Simple) represent minutes

Some example for months

'M' -> 7  (without prefix 0 if it is single digit)
'M' -> 12

'MM' -> 07 (with prefix 0 if it is single digit)
'MM' -> 12

'MMM' -> Jul (display with 3 character)

'MMMM' -> December (display with full name)

Some example for minutes

'm' -> 3  (without prefix 0 if it is single digit)
'm' -> 19
'mm' -> 03 (with prefix 0 if it is single digit)
'mm' -> 19

Answer 4

tl;dr

LocalDate.parse( 
    "01-23-2017" , 
    DateTimeFormatter.ofPattern( "MM-dd-uuuu" )
)

Details

I have a java.util.Date in the format yyyy-mm-dd

As other mentioned, the Date class has no format. It has a count of milliseconds since the start of 1970 in UTC. No strings attached.

java.time

The other Answers use troublesome old legacy date-time classes, now supplanted by the java.time classes.

If you have a java.util.Date , convert to a Instant object. TheInstant class represents a moment on the timeline in UTC with a resolution of nanoseconds (up to nine (9) digits of a decimal fraction).

Instant instant = myUtilDate.toInstant();

Time zone

The other Answers ignore the crucial issue of time zone. Determining a date requires a time zone. For any given moment, the date varies around the globe by zone. A few minutes after midnight in Paris France is a new day, while still “yesterday” in Montréal Québec.

Define the time zone by which you want context for your Instant .

ZoneId z = ZoneId.of( "America/Montreal" );

Apply the ZoneId to get a ZonedDateTime .

ZonedDateTime zdt = instant.atZone( z );

LocalDate

If you only care about the date without a time-of-day, extract a LocalDate .

LocalDate localDate = zdt.toLocalDate();

To generate a string in standard ISO 8601 format, YYYY-MM-DD, simply call toString . The java.time classes use the standard formats by default when generating/parsing strings.

String output = localDate.toString();

2017-01-23

If you want a MM-DD-YYYY format, define a formatting pattern.

DateTimeFormatter f = DateTimeFormatter.ofPattern( "MM-dd-uuuu" );
String output = localDate.format( f );

Note that the formatting pattern codes are case-sensitive. The code in the Question incorrectly used mm (minute of hour) rather than MM (month of year).

Use the same DateTimeFormatter object for parsing. The java.time classes are thread-safe, so you can keep this object around and reuse it repeatedly even across threads.

LocalDate localDate = LocalDate.parse( "01-23-2017" , f );

---

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date , Calendar , & SimpleDateFormat .

The Joda-Time project, now in maintenance mode , advises migration to the java.time classes.

To learn more, see the Oracle Tutorial . And search Stack Overflow for many examples and explanations. Specification is JSR 310 .

Where to obtain the java.time classes?

• Java SE 8 and SE 9 and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport .
• Android
  • The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
  • See How to use ThreeTenABP… .

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval , YearWeek , YearQuarter , and more .

Answer 5

Please change small "mm" month to capital "MM" it will work.for reference below is the sample code.

        Date myDate = new Date();
        SimpleDateFormat sm = new SimpleDateFormat("MM-dd-yyyy");
       
        String strDate = sm.format(myDate);
        
        Date dt = sm.parse(strDate);
        System.out.println(strDate);

Answer 6

It is simple use below codes.

final Date todayDate = new Date();

System.out.println(todayDate);

System.out.println(new SimpleDateFormat("MM-dd-yyyy").format(todayDate));

System.out.println(new SimpleDateFormat("yyyy-MM-dd").format(todayDate));

System.out.println(todayDate);

Answer 7

You may get day, month and year and may concatenate them or may use MM-dd-yyyy format as given below.

Date date1 = new Date();
String mmddyyyy1 = new SimpleDateFormat("MM-dd-yyyy").format(date1);
System.out.println("Formatted Date 1: " + mmddyyyy1);



Date date2 = new Date();
Calendar calendar1 = new GregorianCalendar();
calendar1.setTime(date2);
int day1   = calendar1.get(Calendar.DAY_OF_MONTH);
int month1 = calendar1.get(Calendar.MONTH) + 1; // {0 - 11}
int year1  = calendar1.get(Calendar.YEAR);
String mmddyyyy2 = ((month1<10)?"0"+month1:month1) + "-" + ((day1<10)?"0"+day1:day1) + "-" + (year1);
System.out.println("Formatted Date 2: " + mmddyyyy2);



LocalDateTime ldt1 = LocalDateTime.now();  
DateTimeFormatter format1 = DateTimeFormatter.ofPattern("MM-dd-yyyy");  
String mmddyyyy3 = ldt1.format(format1);  
System.out.println("Formatted Date 3: " + mmddyyyy3);  



LocalDateTime ldt2 = LocalDateTime.now();
int day2 = ldt2.getDayOfMonth();
int mont2= ldt2.getMonthValue();
int year2= ldt2.getYear();
String mmddyyyy4 = ((mont2<10)?"0"+mont2:mont2) + "-" + ((day2<10)?"0"+day2:day2) + "-" + (year2);
System.out.println("Formatted Date 4: " + mmddyyyy4);



LocalDateTime ldt3 = LocalDateTime.of(2020, 6, 11, 14, 30); // int year, int month, int dayOfMonth, int hour, int minute
DateTimeFormatter format2 = DateTimeFormatter.ofPattern("MM-dd-yyyy");  
String mmddyyyy5 = ldt3.format(format2);   
System.out.println("Formatted Date 5: " + mmddyyyy5); 



Calendar calendar2 = Calendar.getInstance();
calendar2.setTime(new Date());
int day3  = calendar2.get(Calendar.DAY_OF_MONTH); // OR Calendar.DATE
int month3= calendar2.get(Calendar.MONTH) + 1;
int year3 = calendar2.get(Calendar.YEAR);
String mmddyyyy6 = ((month3<10)?"0"+month3:month3) + "-" + ((day3<10)?"0"+day3:day3) + "-" + (year3);
System.out.println("Formatted Date 6: " + mmddyyyy6);



Date date3 = new Date();
LocalDate ld1 = LocalDate.parse(new SimpleDateFormat("yyyy-MM-dd").format(date3)); // Accepts only yyyy-MM-dd
int day4  = ld1.getDayOfMonth();
int month4= ld1.getMonthValue();
int year4 = ld1.getYear();
String mmddyyyy7 = ((month4<10)?"0"+month4:month4) + "-" + ((day4<10)?"0"+day4:day4) + "-" + (year4);
System.out.println("Formatted Date 7: " + mmddyyyy7);



Date date4 = new Date();
int day5   = LocalDate.parse(new SimpleDateFormat("yyyy-MM-dd").format(date4)).getDayOfMonth();
int month5 = LocalDate.parse(new SimpleDateFormat("yyyy-MM-dd").format(date4)).getMonthValue();
int year5  = LocalDate.parse(new SimpleDateFormat("yyyy-MM-dd").format(date4)).getYear();
String mmddyyyy8 = ((month5<10)?"0"+month5:month5) + "-" + ((day5<10)?"0"+day5:day5) + "-" + (year5);
System.out.println("Formatted Date 8: " + mmddyyyy8);



Date date5 = new Date();
int day6   = Integer.parseInt(new SimpleDateFormat("dd").format(date5));
int month6 = Integer.parseInt(new SimpleDateFormat("MM").format(date5));
int year6  = Integer.parseInt(new SimpleDateFormat("yyyy").format(date5));
String mmddyyyy9 = ((month6<10)?"0"+month6:month6) + "-" + ((day6<10)?"0"+day6:day6) + "-" + (year6);`enter code here`
System.out.println("Formatted Date 9: " + mmddyyyy9);

Answer 8

see these..

formatting date

DateTimeFormatter

parsing date

Instant with zone