Compare two dates in Java

Question

I need to compare two dates in java. I am using the code like this:

Date questionDate = question.getStartDate(); Date today = new Date();  if(today.equals(questionDate)){     System.out.println("Both are equals"); } 

This is not working. The content of the variables is the following:

• questionDate contains 2010-06-30 00:31:40.0
• today contains Wed Jun 30 01:41:25 IST 2010

How can I resolve this?

Answer 1

Date equality depends on the two dates being equal to the millisecond. Creating a new Date object using new Date() will never equal a date created in the past. Joda Time's APIs simplify working with dates; however, using the Java's SDK alone:

if (removeTime(questionDate).equals(removeTime(today))    ...  public Date removeTime(Date date) {         Calendar cal = Calendar.getInstance();       cal.setTime(date);       cal.set(Calendar.HOUR_OF_DAY, 0);       cal.set(Calendar.MINUTE, 0);       cal.set(Calendar.SECOND, 0);       cal.set(Calendar.MILLISECOND, 0);       return cal.getTime();  } 

Answer 2

I would use JodaTime for this. Here is an example - lets say you want to find the difference in days between 2 dates.

DateTime startDate = new DateTime(some_date);  DateTime endDate = new DateTime(); //current date Days diff = Days.daysBetween(startDate, endDate); System.out.println(diff.getDays()); 

JodaTime can be downloaded from here.