Question

I have a question related to conversion/formatting of date.

I have a date,say,workDate with a value, eg: 2011-11-27 00:00:00
From an input textbox, I receive a time value(as String) in the form “HH:mm:ss”, eg: “06:00:00”

My task is to create a new Date,say,newWorkDate, having the same year,month,date as workDate,and time to be the textbox input value.

So in this case, newWorkDate should be equal to 2011-11-27 06:00:00.
Can you help me figure out how this can be achieved using Java?

Here is what I have so far:

    SimpleDateFormat df = new SimpleDateFormat("HH:mm:ss");
    //Text box input is converted to Date format -what will be the default year,month and date set here?
     Date textBoxTime = df.parse(minorMandatoryShiftStartTimeStr);

     Date workDate = getWorkDate();
     int year = Integer.parseInt(DateHelper.getYYYYMMDD(workDate).substring(0, 4));
     int month = Integer.parseInt(DateHelper.getYYYYMMDD(workDate).substring(4, 6));
     int date = Integer.parseInt(DateHelper.getYYYYMMDD(workDate).substring(6, 8));

     Date newWorkDate = DateHelper.createDate(year, month, day);
    //not sure how to set the textBox time to this newWorkDate.

[UPDATE]: Thx for the help,guys!Here is the updated code based on all your suggestions..Hopefully this will work.:)

 String[] split = textBoxTime.split(":");
             int hour = 0;
               if (!split[0].isEmpty)){ 
               hour = Integer.parseInt(split[0]);}
             int minute = 0;
             if (!split[1].isEmpty()){
             minute = Integer.parseInt(split[1]);}
             int second = 0;
             if (!split[2].isEmpty()){
                second  = Integer.parseInt(split[2]);}

              Calendar cal=Calendar.getInstance();  
              cal.setTime(workDate); 
              cal.set(Calendar.HOUR, hour); 
              cal.set(Calendar.MINUTE, minute);  
              cal.set(Calendar.SECOND, second);  
              Date newWorkDate = cal.getTime(); 

Answer 1

A couple of hints:

1. Use a Calendar object to work with the dates. You can set the Calendar from a Date so the way you create the dates textBoxTime and workDate are fine.
2. Set the values of workDate from textBoxTime using the setXXX methods on Calendar class (make workDate a Calendar)
3. You can use SimpleDateFormat to format as well as parse. Use this to produce the desired output.

You should be able to do this with no string parsing and just a few lines of code.