Auto-input 'y' when prompted in command-line from Java

Question

The program I'm using runs through the command prompt from java using a batch file (following the solutions from Run .exe file from Java from file location, and at one point of time, it will prompt the user for an input which is either a 'y' or 'n' in order to continue the program.

How do I program using java codes such that the value 'y' or 'n' is automatically entered when prompted, without requiring users to enter it manually? I have tried using pipe (following the solutions from How do you enter something at a DOS prompt Programmatically?) but it doesn't work. Any ideas?

Community · Accepted Answer · 2017-05-23 12:05:34Z

2

Grab the InputStream from the Process and write the y into it.

Look at this questions for example code:

edited May 23, 2017 at 12:05

CommunityBot

11 silver badge

answered Jul 17, 2014 at 5:47

BetaRide

16.9k32 gold badges108 silver badges192 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user3847620 Over a year ago

Hi thanks for the answer. I am new to Java so I am a bit confused with the terms used. Based on my understanding of your answer, it means to use the InputStream and the BufferedReader to read the line and finally to use System.out.println to write 'y' into that line?

BetaRide Over a year ago

No. You have to write to the (wrapped) InputStream you get from the process. System.out.println always prints to the console.

Jp Vinjamoori · Accepted Answer · 2014-07-17 05:30:11Z

1

You can do it the old DOS way.

Create a file, say yes.txt. All it should have is y (as per your app expectations). The file can contain responses to multiple prompts each on their own lines

Now you can execute your exe file something like this

myApp.exe < yes.txt

When exe prompts, yes.txt will supply the prompt text

answered Jul 17, 2014 at 5:30

Jp Vinjamoori

1,2716 silver badges17 bronze badges

2 Comments

user3847620 Over a year ago

Do I include that "myApp.exe < yes.txt" under the batch file or after the Runtime and Process?

Jp Vinjamoori Over a year ago

You have to write a batch file with "myApp.exe < yes.txt" and call the batch file from within java program

Collectives™ on Stack Overflow

Auto-input 'y' when prompted in command-line from Java

2 Answers 2

2 Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related