Difficulty writing multiple lines in a Java file

Question

I am writing to a .dat file in Java that will produce results in binary. I am using randmAccessFile to get these results.

I can get my code to work for 1 line, but when I put it into a for loop to create 10 lines of code, I get an Exception.

Here is my code so far:

public static void main (String [] args) throws IOException
{ 
    DateFormat df = new SimpleDateFormat("dd-MM-yy-HH");
    Date date = new Date();
    System.out.println(df.format(date));

    File fileName = new File(df.format(date) + ".dat");
    RandomAccessFile raf = new RandomAccessFile(fileName, "rw");

    for(int i = 0; i < 10; i++)
    {   
        raf.writeLong(Calendar.getInstance(TimeZone.getTimeZone("UTC")).getTimeInMillis());
        raf.writeInt(10);
        raf.writeInt(2);
        raf.write((byte)1);
        raf.writeInt(3);
        raf.close();    
    }
}

If the for loop was taken out, the code will work but trying to run it as is produces the following results;

04-11-13-15
Exception in thread "main" java.io.IOException: Stream Closed
    at java.io.RandomAccessFile.write0(Native Method)
    at java.io.RandomAccessFile.write(Unknown Source)
    at java.io.RandomAccessFile.writeLong(Unknown Source)
    at com.davranetworks.seleniumtests.Example.main(Example.java:28)

Can anyone explain what I am suddenly doing wrong and be able to send me in the right direction?

just seen it and after moving it outside of the loop, it works now — Dan
– Dan, Commented Nov 4, 2013 at 15:58
If your question is answered, please mark an answer as accepted. — Nicky McCurdy
– Nicky McCurdy, Commented Nov 4, 2013 at 16:20

Jayesh · Accepted Answer · 2013-11-04 16:00:14Z

1

Your For Loop will go from 1 to 10.

consider for 1st pass 0

it will execute below lines along with last line which is closing RandomAcessFile raf.

  raf.writeLong(Calendar.getInstance(TimeZone.getTimeZone("UTC")).getTimeInMillis());
        raf.writeInt(10);
        raf.writeInt(2);
        raf.write((byte)1);
        raf.writeInt(3);
        raf.close();

Now for pass 1 it tries to again execute above 6 lines but in first line only it will throw the exception as file is closed and you are trying to operate on that.

answered Nov 4, 2013 at 16:00

Jayesh

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Dan · Accepted Answer · 2013-11-04 15:57:33Z

0

I figured it out, just put the raf.close() outside of the for loop

answered Nov 4, 2013 at 15:57

Dan

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