n00b Java question concerning file reading

[xospec1alk]

alrite i want my java program to read a text file line by line.

for example if the contents of the file were

something
or
other

it would take the 'something' and return it to a variable. then it would take 'or' and do the same thing, and then 'other' and i have no clue how many lines there will be, so whenever it detects enf of file i suppose.

any hlep would be appreciated

 

[Strafe]

You're talking about java.io which has some major revisions in JDK 1.4. I'm sure you can find some online resources, but if you want to be up to date, make sure the info reflects the changes in 1.4. Ivor Horton's Beginning Java 2 (for JDK 1.4) has a few good chapters on reading and writing files.

 

[wfay]

examples @ java.sun.com...
link

 

[manly]

This has nothing to do with new I/O (which has more to do with writing high performance network servers).

He just needs a BufferedReader that wraps a FileReader, and to call readLine() on the reader. Or InputStreams are okay if you don't need Unicode. I.e.

BufferedReader in = new BufferedReader(new FileReader("/tmp/data.txt"));
String s;

while ( (s = in.readLine()) != null) {
// Process s
}

As you can see, readLine() returns null at end-of-file. You'll have to put everything in a try/catch block.

 

[Strafe]

new I/O can apply to all streams, sure it's more complicated by why learn the old way?

 

[wfay]

Originally posted by: manly
This has nothing to do with new I/O (which has more to do with writing high performance network servers).

he might as well learn the NIO instead of old IO. if its not worth doing right, its not worth doing. 🙂

 

[manly]

Originally posted by: wfay

Originally posted by: manly
This has nothing to do with new I/O (which has more to do with writing high performance network servers).

he might as well learn the NIO instead of old IO. if its not worth doing right, its not worth doing. 🙂

No, because unless I'm mistaken java.io is not being deprecated, nor does it have any serious problems besides performance scalability in certain situations (hence the creation of New I/O). Use it if it's the right API for the job.

It would be a different matter if I was advising him to use AWT with the *old* event model.