检查日期字符串是否包含年份

Question

I have two Strings

String withYear = "12/04/1988"

String withoutYear = "10/04"

The date format is MM/dd/yyyy

I am trying to determine whether a string contains a year or not .

Here is my code so far :

Calendar c= Calendar.getInstance();
c.setTime(dt.parse(withYear)); //dt is a SimpleDateFormat 'MM/dd/yyyy'
c.get(Calendar.YEAR) // = 1988

c.setTime(dt.parse(withoutYear));
c.get(Calendar.YEAR);// = 1970

Answer 1

I think the easiest way to do this is to forget about making Date/Calendar objects altogether. You can simply check the String to see how many sections it has:

public static boolean containsYear(String dateStr){
    return dateStr.split("/").length == 3;
}

Answer 2

Your code is working perfectly, when you call dt.parse(withoutYear), the year is set automatically to the Epoch year (1970).

From SimpleDateFormat: http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html

This parsing operation uses the calendar to produce a Date. All of the calendar's date-time fields are cleared before parsing, and the calendar's default values of the date-time fields are used for any missing date-time information. For example, the year value of the parsed Date is 1970 with GregorianCalendar if no year value is given from the parsing operation. (emphasis mine)

If you don't expect any valid year values as 1970 then you can assume all dates with year==1970 were specified without a year.

A more complete solution would be to subclass GregorianCalendar and make the default value for field YEAR = -1;

Answer 3

        String data[] = withYear.split("/");
        String year =null ;
        if(data.length==3){
            year = data[2] ;
            System.out.println(year);
        }

Answer 4

If you want, you can use YodaTime, its very easy to deal with time/dates, more about it here Yoda time getYear() . You can try to parse your String and then getYear().

Hope this helps.