Copying a file.Finding a path to it

Question

I want to copy file to another directory.I know this has been asked million times,I read tons of answers about this but I just can't seem to make it work.This is the code I am currently using:

copyFile(new File(getClass().getResource("/jars/TurnOffClient.jar").toString()),
   new File("C:\\Documents and Settings\\All Users\\Start Menu\\Programs\\Startup\\karioc.jar"));

And this is the method:

public static void copyFile(File sourceFile, File destFile) throws IOException {
    if(!destFile.exists()) {
        destFile.createNewFile();
    }

    FileChannel source = null;
    FileChannel destination = null;

    try {
        source = new FileInputStream(sourceFile).getChannel();
        destination = new FileOutputStream(destFile).getChannel();
        destination.transferFrom(source, 0, source.size());
    }
    finally {
        if(source != null) {
            source.close();
        }
        if(destination != null) {
            destination.close();
        }
    }
}

This is my dir: Directories http://imageshack.com/a/img820/6418/5g3m.png

////////////////////////////////////////////////////////////////////////////////////////// And this is the exception I get:

What do you think `getClass().getResource("/jars/TurnOffClient.jar")` does and why? — Sotirios Delimanolis, Jun 25 '14 at 22:34
The problem here is unique because he's trying to copy the file out of the JAR. — tbodt, Jun 25 '14 at 22:42
getClass gets you the path of where the class is in machine? — ESipalis, Jun 25 '14 at 22:55

tbodt · Accepted Answer · 2014-06-27T22:20:56.617

Standard ways to copy a file don't work because you are trying to copy the file out of the JAR. When you get a file out of a JAR, you can't get a File object for it. You can get a URL, and from that an InputStream.

An existing answer includes code to copy data from one input stream to another. Here it is, adapted for the file inside a JAR:

InputStream in = getClass().getResourceAsStream("/jars/TurnOffClient.jar");
OutputStream out = new FileOutputStream(new File("C:\\Documents and Settings\\All Users\\Start Menu\\Programs\\Startup\\karioc.jar"));

// Transfer bytes from in to out
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) != -1) {
    out.write(buf, 0, len);
}
in.close();
out.close();

your while loop should really be comparing to -1 (EOF) – Brett Okken Jun 26 '14 at 00:06 — Brett Okken, Jun 26 '14 at 00:06

score 0 · Answer 2 · edited May 23 '17 at 10:29

Have you tried using java.nio.Files.copy(); ? There's built in methods for doing this.

If that doesn't work then go ahead and transfer bytes from a file inputstream to an output file stream.

public void copy(File src, File dst) throws IOException {
    InputStream in = new FileInputStream(src);
    OutputStream out = new FileOutputStream(dst);

    // Transfer bytes from in to out
    byte[] buf = new byte[1024];
    int len;
    while ((len = in.read(buf)) > 0) {
        out.write(buf, 0, len);
    }
    in.close();
    out.close();
}

As described here: Standard concise way to copy a file in Java?

Copying a file.Finding a path to it

2 Answers2