How to execute system commands (linux/bsd) using Java

问题

I am attempting to be cheap and execute a local system command (uname -a) in Java. I am looking to grab the output from uname and store it in a String. What is the best way of doing this? Current code:

public class lame {

    public static void main(String args[]) {
        try {
            Process p = Runtime.getRuntime().exec("uname -a");
            p.waitFor();
            BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line=reader.readLine();

            while (line != null) {    
                System.out.println(line);
                line = reader.readLine();
            }

        }
        catch(IOException e1) {}
        catch(InterruptedException e2) {}

        System.out.println("finished.");
    }
}

回答1:

Your way isn't far off from what I'd probably do:

Runtime r = Runtime.getRuntime();
Process p = r.exec("uname -a");
p.waitFor();
BufferedReader b = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = "";

while ((line = b.readLine()) != null) {
  System.out.println(line);
}

b.close();

Handle whichever exceptions you care to, of course.

回答2:

That is the best way to do it. Also you can use the ProcessBuilder which has a variable argument constructor, so you could save a line or two of code

回答3:

What you are doing looks fine. If your command is only returning a single string, you don't need the while loop, just store the reader.readLine() value in a single String variable.

Also, you probably should do something with those exceptions, rather than just swallowing them.

回答4:

I know this is very old but still...

Reading the article here: http://www.javaworld.com/article/2071275/core-java/when-runtime-exec---won-t.html
It is my understanding that you should first read the output and error streams of your executed command and only then waitFor the return value of your process.

来源：https://stackoverflow.com/questions/792024/how-to-execute-system-commands-linux-bsd-using-java

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java

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