uncompress files from a tar using apache commons - prob is duplicate entry

Question

Scenario: Uncompress a tar file using Apache commons.

Problem: The tar i am using is a build tar which gets deployed into a web server. This tar contains duplicate entries like below.

1. appender_class.xml
2. APPENDER_CLASS.xml

when extracting using the below code only appender_class.xml is extracted but i want both the files how can i do that ? Renaming in fly is fine but how can i accomplish that?

public static void untar(File[] files) throws Exception {
        String path = files[0].toString();
        File tarPath = new File(path);
        TarEntry entry;
        TarInputStream inputStream = null;
        FileOutputStream outputStream = null;
        try {
            inputStream = new TarInputStream(new FileInputStream(tarPath));
            while (null != (entry = inputStream.getNextEntry())) {
                int bytesRead;
                System.out.println("tarpath:" + tarPath.getName());
                System.out.println("Entry:" + entry.getName());
                String pathWithoutName = path.substring(0, path.indexOf(tarPath.getName()));
                System.out.println("pathname:" + pathWithoutName);
                if (entry.isDirectory()) {
                    File directory = new File(pathWithoutName + entry.getName());
                    directory.mkdir();
                    continue;
                }
                byte[] buffer = new byte[1024];
                outputStream = new FileOutputStream(pathWithoutName + entry.getName());
                while ((bytesRead = inputStream.read(buffer, 0, 1024)) > -1) {
                    outputStream.write(buffer, 0, bytesRead);
                }
                System.out.println("Extracted " + entry.getName());
            }
    }

Answer 1

Try opening your FileOutputstream like this instead:

File outputFile = new File(pathWithoutName + entry.getName());
for(int i = 2; outputFile.exists(); i++) {
    outputFile = new File(pathWithoutName + entry.getName() + i);
}
outputStream = new FileOutputStream(outputFile);

It should generate a file called APPENDER_CLASS.xml2 if it encounters a previously created file called APPENDER_CLASS.xml. If a APPENDER_CLASS.xml2 exists it will create a APPENDER_CLASS.xml3, ad infinitum.

File.exists() takes case sensitivity into account (windows filenames are case insensitive, whereas unix, linux and mac are case sensitive). Thus with the above code on case insensitive filesystems the file would be renamed and on case sensitive filesystems the file would not be renamed.