Executing a .exe or .linux file in Java during Run time

Question

I am trying to create a function within a Java Class that can execute a .exe or a .linux file during runtime. The program is espresso.exe (for Windows OS) and espresso.linux for (Linux based systems)

Typically, the way to run the program is by going to command line, and going to the folder in which the executable is stored and typing:

(in Command Prompt)

espresso A0.txt > m.txt

or espresso A0.txt (which returns the output in cmd)

(in linux Terminal)

./espresso.linux A0.txt > m.txt

or ./espresso.linux A0.txt (which returns the output in the terminal window)

Here A0.txt is the input argument and m.txt is the file that espresso creates.

I have stored A0.txt and espresso.linux and espresso.exe under a folder src/resources

I tried the following:

 ProcessBuilder pb = new ProcessBuilder("./src/resources/espresso.exe","src/resources/A0.txt",">src/resources/m.txt");
 try {
        Process p = pb.start();
 }catch (IOException ex) {
        Logger.getLogger(NetSynth.class.getName()).log(Level.SEVERE, null, ex);
 }

I also tried:

Runtime rt = Runtime.getRuntime();
Process p = rt.exec("src/resources/espresso.linux src/resources/A0.txt > src/resources/m.txt");
int waitFor = p.waitFor();

Both of them fail to identify the file to be executed and do not run the command. I understand there may be many errors in the 2 approaches. I could use some help to figure out the approach and the code to be written to run the executable file.

Also, is there a path to be mentioned to run espresso.linux? Will /src/resources/espresso.linux suffice?

Thanks in advance.

You can't use an argument like "> something", unless you call a shell. — Ingo, Nov 01 '13 at 21:44

score 2 · Accepted Answer · edited May 23 '17 at 12:21

2

You can't do standard output redirection like this (because the ">" sign is interpreted by the OS shell), see this answer for a working solution: ProcessBuilder redirecting output

Since Java 7 there is a Java-only solution in order to achieve redirecting: http://tamanmohamed.blogspot.co.at/2012/06/jdk7-processbuilder-and-how-redirecting.html

edited May 23 '17 at 12:21

Community

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answered Nov 01 '13 at 21:44

lbalazscs

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These files are stored in src/resources in the Java project's Source Packages. Is there a way to capture the output stream. Also is the path I have provided in the exec() or processbuilder() function correct? – Prashant Vaidyanathan Nov 01 '13 at 22:13

score 2 · Answer 2 · answered Nov 01 '13 at 21:45

2

The > is a shell syntax. If you want to redirect the output to a file you need to use a shell or read the output and write it to a file yourself.

The way you have used > it is just another argument.

answered Nov 01 '13 at 21:45

Peter Lawrey

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I can also use the command espresso A0.txt or ./espresso.linux A0.txt Is there a way to capture the outputstream from espresso that is usually shown in the terminal/cmd window? – Prashant Vaidyanathan Nov 01 '13 at 22:14
1

@PrashantVaidyanathan You can get the output using Process.getOutputStream(). – Peter Lawrey Nov 02 '13 at 08:24

Executing a .exe or .linux file in Java during Run time

2 Answers2