如何将 2019 年 10 月 9 日 12:00:00:000AM 的日期字符串格式化为 dd/MM/yyyy

Question

I have date formatted as Oct 9 2019 12:00:00:000AM . I want to change its format to 09/10/2019 .

So far here is what i tried:

    SimpleDateFormat outs= new SimpleDateFormat("dd/MM/yyyy");
    String newDate= outs.format(invoiceEntity.getTidate()); // where invoiceEntitygetTidate() is the date

But i get error

*java.lang.IllegalArgumentException:

Cannot format given Object as a Date*.

Answer 1

Use Java 8 date time API, you can parse the input string into LocalDate using DateTimeFormatter and then parse it to required format string

String date = "Oct 9 2019 12:00:00:000AM";

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM d yyyy hh:mm:ss:SSSa");

LocalDate local = LocalDate.parse(date,formatter);

System.out.println(local.format(DateTimeFormatter.ofPattern("dd/MM/yyy")));

Or if you have java.util.Date object, convert to java.time classes (specifically, Instant ) and proceed to get your LocalDate object.

Date utilDate = new Date();

String output = utilDate.toInstant()
                        .atZone(ZoneId.systemDefault())
                        .toLocalDate()
                        .format(DateTimeFormatter.ofPattern("dd/MM/yyyy"));

System.out.println(output);

Answer 2

Java 8 introduced new APIs for Date and Time to address the shortcomings of the older java.util.Date and java.util.Calendar.

Issues with the Existing Date/Time APIs

1. Thread Safety – The Date and Calendar classes are not thread safe
2. APIs Design and Ease of Understanding – The Date and Calendar APIs are poorly designed with inadequate methods to perform day-to-day operations.
3. onedDate and Time – Developers had to write additional logic to handle timezone logic with the old APIs, whereas with the new APIs, handling of timezone can be done with Local and ZonedDate/Time APIs.

Fr more idea please refer here

You can use the JAVA 8 Date API feature for converting the date. Example is given below.

String oldDate = "Oct 9 2019 12:00:00:000AM";

// mentioning the input date format
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM d yyyy hh:mm:ss:SSSa");

//converting the date
LocalDate localDate = LocalDate.parse(oldDate,formatter);

//Final date formatted 
String formattedDate=localDate.format(DateTimeFormatter.ofPattern("dd/MM/yyy"));

System.out.println("Old Date :- "+ oldDate);
System.out.println("New Date :- "+formattedDate);

Output

Old Date:- Oct 9 2019 12:00:00:000AM

New Date:- 09/10/2019