Write result from command line in file using Java

Question

I tried to run command line from Java code.

public void executeVcluto() throws IOException, InterruptedException {
    String command = "cmd /c C:\\Users\\User\\Downloads\\program.exe C:\\Users\\User\\Downloads\\file.txt 5 >> C:\\Users\\User\\Downloads\\result.txt";
    Process process = Runtime.getRuntime().exec(command);
    process.waitFor();
    if (process.exitValue() == 0) {
        System.out.println("Command exit successfully");
    } else {
        System.out.println("Command failed");
    }

}

However, the file where output result should be written result.txt is not created. When I execute this command from cmd on windows the file is created and the result is written in it. I get Command exit successfully message. Could someone help me?

score 4 · Accepted Answer · edited May 23 '17 at 12:11

output redirection is shell feature, java Process does not understand that.

Some other alternatives are 1. create a single batch file with above lines and invoke it using ProcessBuilder/Runtime 2. Use ProcessBuilder and redirect output using output streams. Example (it is for shell, will work for batch files too) is here

ProcessBuilder builder = new     ProcessBuilder("cmd", "/c", "C:\\Users\\User\\Downloads\\program.exe", "C:\\Users\\User\\Downloads\\file.txt" , "5");
builder.redirectOutput(new File("C:\\Users\\User\\Downloads\\result.txt"));
builder.redirectError(new File("C:\\Users\\User\\Downloads\\resulterr.txt"));

Process p = builder.start(); // throws IOException

(above is tweaked from Runtime's exec() method is not redirecting the output)

score 0 · Answer 2 · answered Jul 07 '13 at 01:16

0

Try cmd.exe, including a path, if necessary.

You're creating an entirely new process, which is different than giving a command to a shell.

answered Jul 07 '13 at 01:16

Arthur Dent

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Write result from command line in file using Java

2 Answers2