How to get current date and time

[Sharma Vinit]

hi friends,

I wish to use the current year in my program but unable to figure out a way to do this.There's no direct method in the Java docs.

How can i retrieve the current month and year in my program?

Thanks

[pankaj patil]

make use of Calendar class in the java.util package
or make use of Date from the java.util package

java.util.Date()

[Pramod P Deore]

you can also use

  Calendar toDay = Calendar.getInstance();
int year = toDay.get(Calendar.YEAR);  

[Sharma Vinit]

hey guys

how can i compare a date with current date. I have to check the joining date of a student which is received from front end as a string.The joining date should not be greater than today's date.

I have tried the following. Its working but i think there must be a better way out

     String validateDOJ(String doj){

      if(doj.isEmpty() || doj.equals(null))
            return "Empty DOJ.";

        StringTokenizer st = new StringTokenizer(doj, "/"); //the date is passed as dd/mm/yyyy

        int day = Integer.parseInt(st.nextToken());
        int month = Integer.parseInt(st.nextToken());
        int year = Integer.parseInt(st.nextToken());
 
        Calendar today = Calendar.getInstance();
        int currentYear = today.get(Calendar.YEAR);
        int currentMonth = today.get(Calendar.MONTH) + 1;   // since system months start from 0
        int currentDay = today.get(Calendar.DAY_OF_MONTH);
      
        if(year > currentYear)
            return "Invalid joining year(DOJ year cannot be a future year)";
        
        if(year == currentYear){
         
            if(month > currentMonth){
                               return "Invalid month in current year(DOJ month cannot be a future month in same year)";
            }

            if(month == currentMonth){
                                if(day > currentDay){
                                        return "Invalid day in current month(DOJ day cannot be a future day in same month and year)";
                }
            }
        }
       
        return "correct date";
    }

[Jesper de Jong]

Please UseCodeTags when you post source code.

That looks a lot more complicated than it needs to be...

You can use class java.text.SimpleDateFormat to parse a string into a Date object. Then you can use the methods after() or before() of class Date to check if the date is before or after another date.

[pankaj patil]

Look for Date comparison code in java

visit below mention link
http://www.roseindia.net/java/example/java/util/CompareDate.shtml

[Pradeep Katipamula]

Sharma Vinit wrote:
I have tried the following. Its working but i think there must be a better way out

Here's the code.

public boolean validateDOJ(String dateString) throws ParseException { 
    SimpleDateFormat sdf = new SimpleDateFormat("dd/mm/yyyy");
    Calendar today = Calendar.getInstance();
    Date doj = sdf.parse(dateString);
    return today.getTime().after(doj);
}

Hope this is wat you wanted. I;ve returned a boolean, if you really need to send a string please modify.

Pradeep

[Campbell Ritchie]

That doesn't look good. You are either returning true or throwing a checked Exception.

[Rob Spoor]

DateFormat.parse(String, ParsePosition) returns null when the string is invalid. That can be used:

public boolean validateDOJ(String dateString)
{    
    DateFormat sdf = new SimpleDateFormat("dd/mm/yyyy"); 
    Date doj = sdf.parse(dateString, new ParsePosition(0));
    return doj != null && doj.getTime() < System.currentTimeMillis();
}

Not only does this code not throw an exception, it also doesn't create an unnecessary Calendar (and Date from getTime()) object. You can improve this code slightly by checking if the entire String is used in parsing:

public boolean validateDOJ(String dateString)
{    
    DateFormat sdf = new SimpleDateFormat("dd/mm/yyyy"); 
    ParsePosition pos = new ParsePosition(0)
    Date doj = sdf.parse(dateString, pos);
    return doj != null && doj.getTime() < System.currentTimeMillis() && pos.getIndex() == dateString.length();
}

If the parse position's index is not directly at the end of the String there is something else in the String as well. This will occur if the passed String is something like "20/05/2010abc". The added check will make the method return false if that's the case.