(Java) How to get user input without pressing the “enter” key [duplicate]

Answer 1

You need to run your program in some way that doesn't line-buffer user input.

Lots of detail here and some related discussion here.

This code:

public static void main(String[] args) throws IOException {
    System.out.print("hit a key: ");
    System.out.print(System.in.read());
}

and a "Terminal" app on OS X with this:

stty raw -echo

behaves like this when run (where the above code is in a file named Scratch.java, and I typed a single A as input):

$ stty raw && java Scratch
hit a key: 65

Answer 2

You can do something like this:

import java.io.IOException;

public class MainClass {

public static void main(String[] args) {
    int inChar;
    System.out.println("Enter a Character:");
    try {
        inChar = System.in.read();
        System.out.print("You entered ");
        System.out.println(inChar);
    }
    catch (IOException e){
        System.out.println("Error reading from user");
    }
  }
}

so the command

System.in.read()

will read the char that the user have been entered.