尝试从Java运行gsutils永远不会返回

Question

I try to download folders from Google storage on the cloud.

I run from a process of a user that have permissions (when i run from regular terminal on mac it works)

I have this code:

public void runCommand() {
    final Process p;
    try {
        p = Runtime.getRuntime().exec(
            "gsutil -m cp -r gs://my_bucket/705/201609040613/output/html_pages file:/Users/eladb/WorkspaceQa/GsClient/build/resources/main/downloads/");

        new Thread(new Runnable() {
        public void run() {
            BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line = null;

            try {
                while ((line = input.readLine()) != null)
                    System.out.println(line);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }).start();

    p.waitFor();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

but the new thread never returns.

stuck on line:

while ((line = input.readLine()) != null)

Is there any way to download these folders from google cloud otherwise?

Answer 1

This manual copying of stdout data is error prone (you would have to forcefully close the stream to terminate the sub thread) and thankfully, unnecessary since Java 7 :

public void runCommand() {
    try {
        new ProcessBuilder("gsutil", "-m", "cp", "-r",
            "gs://my_bucket/705/201609040613/output/html_pages",
            "file:/Users/eladb/WorkspaceQa/GsClient/build/resources/main/downloads/")
        .inheritIO()
        .start()
        .waitFor();
    } catch(IOException | InterruptedException e) {
        e.printStackTrace();
    }
}

If you don't want to direct all three channels this way, see redirectOutput(File) , redirectOutput(ProcessBuilder.Redirect) , and the similar methods for input and error channel.

---

Only the (default) mode ProcessBuilder.Redirect.PIPE requires you to provide input or receive output while the sub-process is runnig.