How can I add files to a Jar file?

Question

I want to add a series of files previously extracted from other files(already done) to a jar. These files will be overwriting files inside the JAR. What is the most efficien

Answer 1

If someone needs a programmatically answer, here it is.

private static void createJar(File source, JarOutputStream target) {
    createJar(source, source, target);
}

private static void createJar(File source, File baseDir, JarOutputStream target) {
    BufferedInputStream in = null;

    try {
        if (!source.exists()) {
            throw new IOException("Source directory is empty");
        }
        if (source.isDirectory()) {
            // For Jar entries, all path separates should be '/'(OS independent)
            String name = source.getPath().replace("\\", "/");
            if (!name.isEmpty()) {
                if (!name.endsWith("/")) {
                    name += "/";
                }
                JarEntry entry = new JarEntry(name);
                entry.setTime(source.lastModified());
                target.putNextEntry(entry);
                target.closeEntry();
            }
            for (File nestedFile: source.listFiles()) {
                createJar(nestedFile, baseDir, target);
            }
            return;
        }

        String entryName = baseDir.toPath().relativize(source.toPath()).toFile().getPath().replace("\\", "/");
        JarEntry entry = new JarEntry(entryName);
        entry.setTime(source.lastModified());
        target.putNextEntry(entry); in = new BufferedInputStream(new FileInputStream(source));

        byte[] buffer = new byte[1024];
        while (true) {
            int count = in .read(buffer);
            if (count == -1)
                break;
            target.write(buffer, 0, count);
        }
        target.closeEntry();
    } catch (Exception ignored) {

    } finally {
        if ( in != null) {
            try { in .close();
            } catch (Exception ignored) {
                throw new RuntimeException(ignored);
            }
        }
    }
}