Java Network File Transfer Tool -- /dev/random

Java Network File Transfer Tool

Overview

This is a program that allows transferring files over a network from the client to the server. It is part of my prep work for a P2P app I'm slowly working on. It tries to do everything 'correctly', such as buffered socket connections transfer and writing of large blocks at a time, etc. So it is larger than you'd think for a relatively simple task.

Downloads

fileTransClient.java -- The network client code that sends the file to the server
fileTransServer.java -- The network server code that receives files from clients
fileTrans.tar.gz -- Tarball of all the code together with a simple makefile

Conclusion

Works just fine, I eventually need to make it symmetrical to use for the final program(IE if either can act as a server the can communicate both ways). It should be able to handle files up to 2TB, I've tested about 2GB files.

Update

Someone wrote in and pointed out a bug with certain files being transferred(The server was closing before the client). Turns out that Java signs byte values, so any bytes being converted with the MSB as 1 were actually subtracting from the total value, making the server expect a smaller file size. Since Java has no concept of signed vs. unsigned, you have to mask the value and convert to type with more bits. For example:

byte b = 211; // Binary is 11010011
int i = (int)(b);
System.out.println("Value: " + i);

will spit out: Value: -45
So you have to first do a mask each time you are converting a byte:

byte b = 211;
int i = (int)( b & 0xFF );
System.out.println("Value: " + i);

Now you get what you'd expect: Value: 211

Comments(0) 2008-12-19 23:54:25

Add your comment:

Name:

Captcha) 53 - nothing + 4 =

Hardware

Math

Woodwork

Other

- Galvanic Etching Of Brass
Search

projects

no problem can withstand the assault of sustained thinking