我有一个日期（字符串），格式为dd-mon-yyyy，我想将此日期与系统日期进行比较

Question

I have a date in(string) in dd-mon-yyyy format and I want to compare this date with system date.

eg. I have 12-OCT-2010 and I want to compere this with system date in same format

Answer 1

You can use the SystemDateFormat class to parse your String, for example

final DateFormat fmt = new SimpleDateFormat("dd-MMM-yyyy");
final Date input = fmt.parse("12-OCT-2010");
if (input.before(new Date()) {
     // do something
}

Note that SimpleDateFormat is not threadsafe, so needs to be wrapped in a ThreadLocal if you have more than one thread accessing your code.

You may also be interested in Joda , which provides a better date API

Answer 2

Use SimpleDateFormat http://download.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html

    SimpleDateFormat f = new SimpleDateFormat("dd-MMM-yyyy");
    String d = "12-OCT-2010";
    try {
        Date formatted = f.parse(d);
        Date sysDate = new Date();
        System.out.println(formatted);
        System.out.println(sysDate);
        if(formatted.before(sysDate)){
            System.out.println("Formatted Date is older");
        }
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

Answer 3

I would recommend using Joda Time. You can parse that String into a LocalDate object very simply, and then construct another LocalDate from the system clock. You can then compare these dates.

Answer 4

Using simpledateformat -

    String df = "dd-MMM-yyyy";
    SimpleDateFormat sdf = new SimpleDateFormat(df);
    Calendar cal = Calendar.getInstance();

    /* system date */
    String systemdate = sdf.format(cal.getTime());
    /* the date you want to compare in string format */
    String yourdate = "12-Oct-2010";
    Date ydate = null;
    try {
        ydate = sdf.parse(yourdate);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    yourdate = sdf.format(ydate);
    System.out.println(systemdate.equals(yourdate) ? "true" : "false");