CODEWITHSUNDEEP
javaprocessinputstreamreader
Akshat Sharma
Akshat Sharma

Reputation: 3

Process Builder printing the output without any sysout, i want to store the output in List<String>

I want to store the list of folders with name ending with MS present at PROJECT_LOCATION in a List ===>

  ProcessBuilder processBuilder = new ProcessBuilder().directory(Paths.get(PROJECT_LOCATION)
        .toFile())
        .command("cmd.exe",
             "/c",
             "dir /b *MS;")
        .inheritIO()
        .redirectErrorStream(true);
  Process process = processBuilder.start();

this much code is prinitng the names of folders ending with MS, but i want to store the values in a List

I tried =>

        List<String> msList=new ArrayList<>();  
        BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String line;
        while ((line = in.readLine()) != null) {  
            msList.add(line);
        }
        process.waitFor();
        System.out.println("ok!    "+  msList.size());

but the list size is printing to be 0. It is not reading the InputStream Lines. Does it not support for these kind of commands.....?

Console output===>

CartMS
CustomerMS
PaymentMS
ProductMS
ok!    0

Upvotes: 0

Views: 50

Answers (1)

Rob Spoor
Rob Spoor

Reputation: 9090

Why are you starting an external program to list files when there's a much better alternative?

List<String> msList;
try (Stream<Path> stream = Files.walk(Paths.get(PROJECT_LOCATION), 1)) {
    msList = stream.filter(Files::isRegularFile) // also filters out PROJECT_LOCATION itself
            .map(f -> f.getFileName().toString())
            .filter(f -> f.endsWith("MS"))
            .toList(); // for older Java versions: .collect(Collectors.toList())
}

Or without streams:

List<String> msList = new ArrayList<>();
try (DirectoryStream<Path> stream = Files.newDirectoryStream(Paths.get(PROJECT_LOCATION), "*MB")) {
    for (Path file : stream) {
        msList.add(file.getFileName().toString());
    }
}

Upvotes: 1

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