How to get a month as an integer from the given date and print as month name format (“MMM”)

I am new to Java and couldnt retrieve the month while using the below code instead month value is set to 0. Please advise the mistakes that i have done here.

*

for(int i=0;i<this.input.size();i++)
{
SimpleDateFormat sf = new SimpleDateFormat("dd/mm/yyyy");

Date purchasedate;
try {
String details = input.get(i);
String detailsarr = details.split(",");
purchasedate = sf.parse(detailsarr[1]);
Calendar cal = Calendar.getInstance();
cal.setTime(purchasedate);
int month = cal.get(Calendar.MONTH);


*
After getting the above month as an integer, Could you please advise if there is anyway to print the above month value as "MMM" format?

SimpleDateFormat

Date

Calendar

SimpleDateFormat

java.time

java.util.Date

java.util.Calendar

java.text.SimpleDateFormat

3 Answers
3

tl;dr

LocalDate.parse( // Represent a date-only value, without time-of-day and without time zone.
"23/01/2018" , // Tip: Use standard ISO 8601 formats rather than this localized format for data-exchange of date-time values.
DateTimeFormatter.ofPattern( "dd/MM/uuuu" )
) // Return a `LocalDate` object.
.getMonth() // Return a `Month` enum object representing the month of this date.
.getDisplayName( // Automatically localize, generating text of the name of this month.
TextStyle.SHORT , // Specify (a) how long or abbreviated, and (b) specify whether used in stand-alone or combo context linguistically (irrelevant in English).
Locale.US // Specify the human language and cultural norms to use in translation.
) // Returns a `String`.


See this code run live at IdeOne.com.

Jan

java.time

The modern approach uses the java.time classes that supplanted the terrible Date/Calendar/SimpleDateFormat classes.

Date

Calendar

SimpleDateFormat

Tip: When exchanging date-time values as text, use the ISO 8601 standard formats rather than using text meant for presentation to humans. For a date-only value, that would be YYYY-MM-DD such as 2018-01-23.

LocalDate

The LocalDate class represents a date-only value without time-of-day and without time zone.

LocalDate

DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd/MM/uuuu" ) ;
LocalDate ld = LocalDate.parse( "23/01/2018" , f ) ;


Month

Retrieve the month as a Month enum object.

Month

Month m = ld.getMonth() ;


Ask that Month enum to generate a String with text of the name of the month. The getDisplayName method can automatically localize for you. To localize, specify:

Month

String

getDisplayName

TextStyle

Locale

Code:

String output = m.getDisplayName( TextStyle.SHORT , Locale.US ) ;


Notice that we had no use of an integer number to represent the month. Using an enum object instead makes our code more self-documenting, ensures valid values, and provides type-safety.

So I strongly recommend passing around Month objects rather than mere int integer numbers. But if you insist, call Month.getMonthValue() to get a number. The numbering is sane, 1-12 for January-December, unlike the legacy classes.

Month

int

Month.getMonthValue()

int monthNumber = ld.getMonthValue() ;


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.

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.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

java.sql.*

Where to obtain the java.time classes?

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.

Interval

YearWeek

YearQuarter

DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("dd/MM/uuuu");

String dateStringFromInput = "29/08/2018";
LocalDate purchasedate = LocalDate.parse(dateStringFromInput, dateFormatter);

int monthNumber = purchasedate.getMonthValue();
System.out.println("Month number is " + monthNumber);


Running the above snippet gives this output:

Month number is 8

Note that contrary to Calendar LocalDate numbers the months the same way humans do, August is month 8. However to get the month formatted into a standard three letter abbreviation we don’t need the number first:

Calendar

LocalDate

Locale irish = Locale.forLanguageTag("ga");
DateTimeFormatter monthFormatter = DateTimeFormatter.ofPattern("MMM", irish);

String formattedMonth = purchasedate.format(monthFormatter);
System.out.println("Formatted month: " + formattedMonth);


Formatted month: Lún

Please supply your desired locale where I put Irish/Gaelic. Java knows the month abbreviations in a vast number of languages.

Apart from using the long outdated date and time classes, SimpleDateFormat, Date and Calendar, format pattern letters are case sensitive (this is true with the modern DateTimeFormatter too). To parse or format a month you need to use uppercase M (which you did correctly in your title). Lowercase m is for minute of the hour. SimpleDateFormat is troublesome here (as all too often): rather than telling you something is wrong through an exception it just tacitly defaults the month to January. Which Calendar in turn returns to you as month 0 because it unnaturally numbers the months from 0 through 11.

SimpleDateFormat

Date

Calendar

DateTimeFormatter

M

m

SimpleDateFormat

Calendar

java.time

Simple way of doing this is

Calendar cal = Calendar.getInstance();
Date d = cal.getTime();
SimpleDateFormat sdf = new SimpleDateFormat("MMM");
System.out.println(sdf.format(d));


In your case modify snippet like below:

SimpleDateFormat sf = new SimpleDateFormat("dd/mm/yyyy");
Date purchasedate;
try
String details = input.get(i);
String detailsarr = details.split(",");
purchasedate = sf.parse(detailsarr[1]);
SimpleDateFormat sdf = new SimpleDateFormat("MMM");
String month = sdf.format(purchasedate);



Jan

SimpleDateFormat

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