Writing object in text file

Question

I am trying to write an object(Transaction) in text file. The Transaction object contains card no, amount, date. I need to write the object in text file as below with some gaps.

 Card no      Amount      Date

  12335       900.00     29/09/2010

I have used ObjectOutputStream to write the object in the file. But I couldn't able to give the gaps in this case.

How to write the transaction object in a file with some gaps, so that it can be aligned with header?

Any help is appreciated

You can't serialise an object in this way, you need to write the "text" represented by the text to a text file, using maybe something like `String#format` — MadProgrammer, Oct 01 '13 at 04:08
Deserialization will give you the same object you serialized. Read this post http://stackoverflow.com/questions/11653374/whats-the-difference-between-serialization-and-simply-store-the-object-on-disk — Sunil Manheri, Oct 01 '13 at 04:13

score 0 · Answer 1 · answered Oct 01 '13 at 03:52

0

Why are you concerned about gaps in ObjectOutputStream. Its mainly used for writing to file and recreating objects back. If you want to use it to write it to a file in a human readable format suggest you to use normal file output stream and not object output stream.

answered Oct 01 '13 at 03:52

Akhil K Nambiar

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Thank you for your quick reply. In normal file output stream how to provide gaps and write it in a file at single stretch? – Ramya Oct 01 '13 at 03:56
@Ramya hope this link helps http://www.tutorialspoint.com/java/java_filewriter_class.htm – Akhil K Nambiar Oct 01 '13 at 03:59
Using filewriter I was able to write the object with out gaps. How to specify the position to write the object in this position. – Ramya Oct 01 '13 at 04:09

score 0 · Answer 2 · answered Oct 01 '13 at 04:18

I have no idea what your Transaction object looks like. But this should provide some clues. Note System.out.printf(). You can substitute your own output streams. I threw in extra stuff on the Calendar object just so you can get a sense of it...

private class Transaction {
    public int cardno;
    public BigDecimal amt;
    public Date someDate;
}

public void zz2() {
    Transaction t = new Transaction();
    t.cardno = 12335;
    t.amt = new BigDecimal("900.00");

    Calendar cal = GregorianCalendar.getInstance(TimeZone.getTimeZone("GMT"));
    cal.set( Calendar.YEAR,        2013 );
    cal.set( Calendar.MONTH,       9);  // zero offset so 9 = Oct              
    cal.set( Calendar.DATE,        1 ); // NOT zero offset...                  
    cal.set( Calendar.HOUR_OF_DAY, (15) );  // 3PM                             
    cal.set( Calendar.MINUTE,      30 );
    cal.set( Calendar.SECOND,      44 );
    cal.set( Calendar.MILLISECOND, 700 );

    t.someDate = cal.getTime();

    DateFormat df = new SimpleDateFormat("MM/dd/yyyy");

    String s = df.format(t.someDate);

    System.out.println("Card no      Amount      Date");
    System.out.printf ("%6d %12s   %10s\n",
                      t.cardno,
                      t.amt,
                      s);
}

score 0 · Answer 3 · answered Oct 09 '13 at 06:45

0

Maybe I'm missing something, but have you tried using tabs (escaped in a string to "\t") in the positions you need the gaps?

System.out.println("Card no\tAmount\tDate");

Similarily for the println statement where you're outputting the values.

answered Oct 09 '13 at 06:45

Vegard

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Writing object in text file

3 Answers3