I’ve date format like Apr 1 2022 12:00:00:000AM and looking to convert it into 20220401 (yyyyMMdd).How can we convert the Date format
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
public class Demo {
public static void main(String[] args) {
String value = "Apr 1 2022 12:00:00:000AM";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM d yyyy hh:mm:ss.SSSa");
LocalDateTime dateTime = LocalDateTime.parse(value, formatter);
System.out.println(dateTime);
}
}
When run this code giving me below error
Exception in thread "main" java.time.format.DateTimeParseException: Text 'Apr 1 2022 12:00:00:000AM' could not be parsed at index 4
at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
at java.time.LocalDateTime.parse(LocalDateTime.java:492)
at Demo.main(Demo.java:10)
EDIT-1
As per Basil Bourque suggestions, still below is not working
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
public class Demo {
public static void main(String[] args) {
String value = "Apr 1 2022 12:00:00:000AM".replace( " " , " " ) ;
Locale locale = new Locale.Builder().setLanguage("en").setRegion("US").build();
DateTimeFormatter formatter =
DateTimeFormatter.
ofPattern("MMM d yyyy hh:mm:ss.SSSa")
.withLocale( locale ) ;
LocalDateTime dateTime = LocalDateTime.parse(value, formatter);
System.out.println(dateTime);
}
}
Still the same error
Exception in thread "main" java.time.format.DateTimeParseException: Text 'Apr 1 2022 12:00:00:000AM' could not be parsed at index 19
6
tl;dr
- Your defined formatting pattern fails to match your input, in multiple ways.
- Always specify a
Localewhen parsing localized text. - Where possible, use only ISO 8601 standard formats to exchange date-time values textually.
SPACE character
You have two SPACE characters between your first two parts. Replace with a single SPACE.
String value = "Apr 1 2022 12:00:00:000AM".replace( " " , " " ) ;
Alternatively, you may indicate an optional SPACE in your formatting pattern with square brackets: [ ].
COLON character
Your formatting pattern says to expect a FULL STOP (.) character between second and the AM/PM. But your input string has a COLON (:) there.
Change your formatting pattern to match your input.
Locale
Specify a Locale explicitly rather than implicitly relying upon the JVM’s current default.
Locale locale = new Locale( "en" , "US" ) ; // In Java 19+, use `Locale.of`.
DateTimeFormatter formatter =
DateTimeFormatter
.ofPattern("MMM d yyyy hh:mm:ss:SSSa");
.withLocale( locale ) ;
The Locale specifies the human language and the cultural norms to be used in localization. This includes the spelling of the month name, and the use of punctuation.
Generating text
To generate text in your desired, extract a LocalDate to focus on the date without the time of day.
LocalDate ld = myLocalDateTime.toLocalDate() ;
Then define a formatter for your format.
No need to define a custom formatter in your case. Your desired formatter complies with the “basic” form of the ISO 8601 standard format that minimizes punctuation. Java provides a constant for that particular format: BASIC_ISO_DATE.
String output = ld.format( DateTimeFormatter.BASIC_ISO_DATE ) ;
Example code
String input = "Apr 1 2022 12:00:00:000AM".replace( " " , " " ) ;
Locale locale =new Locale( "en" , "US" ) ; // In Java 19+, use `Locale.of`.
DateTimeFormatter formatter =
DateTimeFormatter
.ofPattern("MMM d yyyy hh:mm:ss:SSSa")
.withLocale( locale );
LocalDateTime ldt = LocalDateTime.parse( input , formatter ) ;
LocalDate ld = ldt.toLocalDate();
String output = ld.format( DateTimeFormatter.BASIC_ISO_DATE ) ;
System.out.println( output ) ;
See this code run at Ideone.com.
ISO 8601
Avoid parsing text in custom formats, and avoid parsing localized text.
The international standard ISO 8601 defines clear, simple, reliable formats for exchanging date-time values as text. These are easily read by machine as well as by humans across cultures.
The java.time classes use ISO 8601 by default when parsing/generating text.
The ideal solution is to educate the publisher of your data about the benefits of using ISO 8601.
Your input should be: 2022-04-01T00:00.
3
You have several errors in your DateTimeFormatter.
- There are two spaces between the month and the day. That’s why Java is giving you the following error:
java.time.format.DateTimeParseException: Text ‘Apr 1 2022 12:00:00:000AM’ could not be parsed at index 4
-
As @Basil has written in his answer, you better pass a
Localeto parse correctly your date, sinceAprwon’t be parsed if you’re on a different system like the Italian one, for example, which accepts onlyapr. -
Lastly, you have a colon (
:) to separate seconds and milliseconds, while your value contains a dot (.).
This is the fixed version of your code:
public class Demo {
public static void main(String[] args) {
String value = "Apr 1 2022 12:00:00:000AM";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM d yyyy hh:mm:ss:SSSa", Locale.US);
LocalDateTime dateTime = LocalDateTime.parse(value, formatter);
System.out.println(dateTime);
}
}
Disclaimer: I made changes only to your DateTimeFormatter supposing that you would have to abide to this specific format. However, if you are constructing the values to parse, make sure to not add extra white spaces and use standard symbols to separate each group.
8