Issue while running Linux Command using Java?

Question

I am running command using Java and getting no output.

Process p;
Runtime run = Runtime.getRuntime();  
    String s1 = "queryData 1005017 --format '\"%s" scope'";

    System.out.println("Command is " + s1);


    try {  

        p = run.exec(s1);  
        BufferedReader br = new BufferedReader(
                new InputStreamReader(p.getInputStream()));
            while ((s = br.readLine()) != null)
                System.out.println("line: " + s);
        p.getErrorStream();  
        p.waitFor();

    }

While the same command ---> queryData 1005017 --format '"%s" scope' runs without any issue. Wondering am i missing any thing while handling either double quote, or % sign?

Assuming that your missing backslash is just a typo (does your program compile?), have you tried checking p.exitValue() after the waitFor to see if it terminated successfully or not? — RealSkeptic
– RealSkeptic, Commented Oct 7, 2015 at 21:38
So, it exited unsuccessfully. Try reading the error stream instead of the input stream and see what kind of error it gives you. — RealSkeptic
– RealSkeptic, Commented Oct 7, 2015 at 21:49

ursa · Accepted Answer · 2015-10-07 22:04:22Z

2

Try do NOT use strings to start processes from Java. Correct way is usage of ProcessBuilder:

p = new ProcessBuilder(Arrays.asList(
    "queryData", "1005017", "--format", "\"%s\" scope")).start();

answered Oct 7, 2015 at 22:04

ursa

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1 Comment

Ammad Over a year ago

Thanks. That fix that.

Marc B · Accepted Answer · 2015-10-07 21:36:10Z

2

You didn't escape the internal quotes properly:

String s1 = "queryData 1005017 --format '\"%s" scope'";
            ^--start java string             ^--end java string
                                               ^^^^^ what's this mean to java?

You probably want

String s1 = "queryData 1005017 --format '\"%s\" scope'";
                                             ^--note this

instead.

answered Oct 7, 2015 at 21:36

Marc B

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1 Comment

RealSkeptic Over a year ago

Well, that wouldn't compile, OP says it doesn't return output. Perhaps it's just a typo.

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