reading from a file in java

sixpack's little hat

The following code is part of a bigger application.Compiles and runs fine but whenever i try to open a file with the JFileChooser i get an ioException.Specifically the one on line 49.

catch (IOException ioException) {
JOptionPane.showMessageDialog(this, "Error Opening File",
"Error", JOptionPane.ERROR_MESSAGE);
}


Can't see what problem is ...
Quite possibly something stupid/obvious as i'm fairly new to java.

Draupnir

youre gonna need to show the code for opening the file for anyone to now why its firing an error, just post up the try block which is linked to that catch

OfflerCrocGod

Emm do you mean a HeadlessException? that's what the Java site says it throws.

Draupnir

sorry bout that, i got your code there now, I reckon for a start you should remove the return statement from line 34.

but i think your main problem is that your FileInputStream should be a FileOutputStream. give that a go

Draupnir

dosent a headless exception actually relate to graphical displays? im pretty sure the problem is the input streams should be output streams, then i reckon it will work, if what you are trying to do is open the files.

OfflerCrocGod

How about making fileName a set file just for testing purposes?, hard code it to be a file you know you can get to. Ignore what I sayd above^^ I'm half asleep.

Draupnir

pity the chap who had the problem aint around so he could try it out.

OfflerCrocGod

Originally posted by Draupnir
dosent a headless exception actually relate to graphical displays?

Yep it does:D, damn, you beat me to it!, I'm going to bed before I make any bigger a fool of myself.

sixpack's little hat

Its definitely supposed to be an ObjectInputStream. The commented code for output was just to see would it open a file when it was for output,which it did.

System.out.println(fileName);

does print out the directory/file i select with the JFileChooser but for some reason it doesn't open this file hence the ioException.

sixpack's little hat

changing the ioException catch to ..

catch (IOException ioException) {
JOptionPane.showMessageDialog(this, "Error Opening File"
+ ioException.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
}


the error message says "invalid stream header".

googled it but didn't find anything that helped.

Draupnir

if you wanna open a file, the output stream does the trick not the input stream, of this i am certain

Lu[ifer

surely an output stream is used for writing to a file, and an input stream is used for reading from a file.

Hobbes

does ioException.getMessage() print the stacktrace?

or try ioException.printStackTrace()

Show you exactly the problem line.