Calling Perl script from Java (JAX-WS in Eclipse)

Question

I have a JAX-WS webservice that receives a string as parameter, calls a Perl script, and returns the string converted to upper case. It is running on Tomcat 8 (localhost on Eclipse).

When I type from the console:

curl -X POST --data "mystring=HelloWorld" http://localhost:8080/MyServices/api/generatePath

Everything works except for the Perl call. On the debugger I see that line is executed, but apparently nothing happens (not even errors). If I run perl /home/me/workspace/match.pl from the console it works perfectly. The path of the match.pl file is correct.

In addition, process.exitValue() return 2.

@Path("/")
public class MyServices {
    @POST
    @Path("/generatePath")
    @Produces(MediaType.APPLICATION_JSON)

    public Response generatePathService(
            @FormParam("mystring") String myString) {

        Process process = null;

        try {
            process = Runtime.getRuntime().exec("perl /home/me/workspace/match.pl --lang en");
        }
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 

        return Response.status(200).entity(myString.toUpperCase()).build();
    }
}

Answer 1

I got similar stuff some time ago. The solution for me was to 'accept' the output of the program. Something like this:

Process p = Runtime.getRuntime().exec(cmd);
final InputStream is = p.getInputStream();
new Thread(new Runnable() {
    @Override
    public void run() {
        try {
            while (is.available() != 0) {
                is.read();
            }
        } catch (IOException ex) {
        }
    }
}).start();

You should also try to get the error stream with p.getErrorStream(). An alternative could be to change your perl program in that way that there is nothing printed to standard out or error out.

Or you call a shell script and redirect the output to dev/null (someting like ´blabla>/dev/null`.