Question about DataOutputStream

[Pojahn_M]

I have created a binary file with DataOutputStream. It contains some binary text.
I want to append text to the end of this file. How to do it?
If I was using RandomAccessFile, I could just move the pointer to the end, but here I dont know how to.

[sunde887]

You can have an underlying fileoutputstream which uses the append constructor, check the java 6 Apis.

[Norm]

Look at the FileOutputStream's constructor. It has a parameter to append output to the end of the file.

[Pojahn_M]

I get exception. I dont see how. First, I print these to a binary file:

		String f = "ttest.txt";

		FileOutputStream sout = new FileOutputStream (f);
		BufferedOutputStream poo = new BufferedOutputStream (sout);
		DataOutputStream fout = new DataOutputStream (poo);

		fout.writeInt (10);
		fout.writeInt (23215);
		fout.writeChar ('A');
		fout.writeLong (60000950);

		fout.close ();
		sout.close ();
		poo.close ();

Then I append a string the the end of the file in a new program, which I ran after the program above:

		FileOutputStream sout = new FileOutputStream (f, true);
		BufferedOutputStream poo = new BufferedOutputStream (sout);
		DataOutputStream fout = new DataOutputStream (poo);

		fout.writeUTF ("hej"); //This string should be at the end of ttest.txt

		//Time to read all this:
		
		FileInputStream fi = new FileInputStream (f);
		BufferedInputStream foo = new BufferedInputStream (fi);
		DataInputStream fin = new DataInputStream (foo);

		System.out.println (fin.readInt ());
		System.out.println (fin.readInt ());
		System.out.println (fin.readChar ());
		System.out.println (fin.readLong ());
		System.out.println (fin.readUTF ()); //This should read the appended text(hej), but I get exception
		fin.close ();
		foo.close ();
		fi.close ();

[Norm]

I get exception

Please copy and paste here the full text of the error message.

Did you close the file before trying to read it?

[Pojahn_M]

http://img225.imageshack.us/img225/561/quickc.jpg

[Norm]

Did you close the file before trying to read it?

[Pojahn_M]

What do you mean by close the file? If you mean close the stream, then yes, I have
fout.close ();
sout.close ();
poo.close ();
btw its a runtime exception.

[Norm]

What about after this:
fout.writeUTF ("hej"); //This string should be at the end of ttest.txt

[Pojahn_M]

shit man, I cant believe I make mistakes like that!!!!
anyway, thanks. Works now.

[Tolls]

As a note, you only need to close the DataStreams. They'll close the streams they are wrapping.