CODEWITHSUNDEEP
javaunixextracttar
Dinessh
Dinessh

Reputation: 21

Runtime.getRuntime.exec() not working for the linux command "tar -xvf filename.tar"

I am trying to untar a file on a Unix machine, using a Java batch application.

Source Code:

String fileName = "x98_dms_12";
       
Runtime.getRuntime().exec("gunzip "+ fileName + ".tar.gz");
System.out.println(" Gunzip:"+"gunzip "+ fileName + ".tar.gz");

Runtime.getRuntime().exec("tar -xvf "+ fileName + ".tar");
System.out.println(" Extract:tar -xvf "+ fileName + ".tar");

Problem Description:

When I run the batch program it does not (completely) work. Only the gunzip command works, converting my fileName.tar.gz to fileName.tar. But the untar command does not seem to do anything, and there is no error or exception in my log or Unix console.

When I run the same commands in a Unix prompt they work fine.

Notes:

  1. The path of execution is correct because it converts my *.tar.gz to *.tar
  2. I cannot use "tar -zxvf fileName.tar.gz" since the attribute "z" does not work on my system.
  3. There is no error or exception thrown.

Please do help.

Upvotes: 1

Views: 4351

Answers (3)

Dinessh
Dinessh

Reputation: 21

The problem is the commands which we give is UNIX command so it wont work in windows environment. I had written a script file to overcome this problem thanks all for you help. The Runtime.getRuntime.exec() will take some time to execute the command given so after each exec() give thread.wait(3000) to complete the process and goto next thread.

Upvotes: 0

Perception
Perception

Reputation: 80603

A couple of things:

  • The tar command will expand a file relative to your working directory, which might need to be set for your Java Process objects
  • You should wait for the unzip process to complete before launching into the untar process
  • You should process the output streams from the processes.

Here is a working example that you can extend/adapt. It uses a separate class to deal with the process output streams:

class StreamGobbler implements Runnable {
    private final Process process;

    public StreamGobbler(final Process process) {
        super();
        this.process = process;
    }

    @Override
    public void run() {
        try {
            final BufferedReader reader = new BufferedReader(
                    new InputStreamReader(process.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }

            reader.close();
        } catch (final Exception e) {
            e.printStackTrace();
        }
    }
}

public void extractTarball(final File workingDir, final String archiveName)
        throws Exception {
    final String gzFileName = archiveName + ".tar.gz";
    final String tarFileName = archiveName + ".tar";

    final ProcessBuilder builder = new ProcessBuilder();
    builder.redirectErrorStream(true);
    builder.directory(workingDir);
    builder.command("gunzip", gzFileName);
    final Process unzipProcess = builder.start();

    new Thread(new StreamGobbler(unzipProcess)).start();
    if (unzipProcess.waitFor() == 0) {
        System.out.println("Unzip complete, now untarring");

        builder.command("tar", "xvf", tarFileName);
        final Process untarProcess = builder.start();
        new Thread(new StreamGobbler(untarProcess)).start();
        System.out.println("Finished untar process. Exit status "
                + untarProcess.waitFor());
    }
}

Upvotes: 2

fmodos
fmodos

Reputation: 4568

The code below will print the output of the command executed. Check if it returns any error.

Process p = Runtime.getRuntime().exec("tar -xvf "+ fileName + ".tar");  
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));  
String line = null;  
while ((line = br.readLine()) != null) {  
     System.out.println(line);  
}

Upvotes: 0

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