Century 的日期格式

Question

I there a way to format dates which contain century in it to common format. Format date in cyymmdd to MM/dd/yyyy.

Example,

Convert 1140711 to o7/11/2014

Answer 1

If you are talking about converting a String in format:

1140711

to

07/11/2014

    DateFormat df1 = new SimpleDateFormat("yyddMM");
    DateFormat df2 = new SimpleDateFormat("dd/MM/yyyy");
    String dateString = "1140711";

    System.out.println(df2.format(df1.parse(dateString.substring(1, dateString.length()))));

Answer 2

As far as I know the only date-time-library which is capable of processing century fields is Joda-Time.

LocalDate date = DateTimeFormat.forPattern("CyyMMdd").parseLocalDate("1140711");
System.out.println("Century=" + date.getCenturyOfEra()); // 20
String usFormat = DateTimeFormat.forPattern("MM/dd/yyyy").print(date);
System.out.println(usFormat); // output: 07/11/2014

As you can see the input digit "1" for century is simply ignored because Joda-Time only evaluates the other fields to a valid date. Personally I would reject such a century input because we are in 21th of century with the century number 20, not 1. So Joda-Time has its limits here, but are you really sure that you have a century of 1 in your input, or is it just a typo?

Answer 3

I had to do the opposite thing, convert date to cyyMMdd.

    String centuryCharacterOfDateFormat(LocalDate valueDate) {
    int year = valueDate.getYear();
    int yearMinus1900 = year - 1900;

    if (yearMinus1900 < 0) {
        throw new PipRuntimeException("Invalid value date, because it is before 1900. " + valueDate);
    } else if (yearMinus1900 < 100) {
        return "0";
    } else {
        String strVal = String.valueOf(yearMinus1900);
        char hundredthChar = strVal.charAt(strVal.length() - 3);
        return String.valueOf(hundredthChar);
    }
}

You could use the similar logic to do the opposite conversion. To get year, you could add 1900 and hundreds of the first character.

Answer 4

In below method in example date string follow the century date format "CYYMMDD" where C for century, YY for year, MM for month and DD for day. Century values aredescribe below: if Century value is 0 then it will represent 20th century, years b/w 1900 to 1999. if Century value is 1 then it will represent 21st century, years b/w 2000 to 2999.

public LocalDate convertedDate () { String dateString = "1230124";

int century = Integer.parseInt(dateString.substring(0, 1));
int year = Integer.parseInt(dateString.substring(1, 3));
int month = Integer.parseInt(dateString.substring(3, 5));
int day = Integer.parseInt(dateString.substring(5, 7));

LocalDate ld= LocalDate.of((century + 19) * 100 + year, month, day);

System.out.printl**strong text**n("Converted Date : "+ld);

return ld; }