Multiple inputs for Java Runtime

[Mani Venkata Kanth]

I have a batch file which will 3 inputs one by one.

Its like 'changepassword.bat' with below inputs:

Old Pwd:
New Pwd:
Confirm Pwd:

User need to enter each input and press enter to enter second input.

Now, I am planning to simulate the same in java program.
For this I am using Runtime.exec();
I am writting inputs to outputStream which is the process.getOutputStream() like below:

out.write(bytes1);
out.write(System.getProperty("line.separator").getBytes());
out.write(bytes2);
out.write(System.getProperty("line.separator").getBytes());
out.write(bytes2);
out.flush();
out.close();

the process is being started and keep on waiting for the input.

I am assuming that the process is taking all my data written to stream as single input like ,
(byte1\nbyte2\nbyte3)
and waiting to either <enter> event or for other inputs.

Please help me solving this issue. or suggest any other approach.

[N Sahni]

Hi,

This topic should give you different approaches for reading inputs in Java. we-ask-user-input-writing

[Mani Venkata Kanth]

Hi Sahni,

My question is not reading the input dynamically... its about writting multi line input to the Java Runtime Process.

Thanks

[N Sahni]

ohh I took the question in other way.

In this case, may be you can parameterize you batch file and pass all the inputs as parameters to the batch file.

[Darryl Burke]

Have you implemented all recommendations in all the sections of When Runtime.exec() won't? If not, first make sure you're consuming the output and error streams.

Even with that, I could make input to a .BAT work only by flush()ing the stream after each output and following that with a Thread.sleep(50). Maybe someone with a better understanding of batch files could explain why and/or suggest a better approach.