AVAJAVA Web Tutorials

(Continued from page 1)

With JavaSW 1.5, you can use the Scanner class to wrap System.in, and call nextLine() on the Scanner object to read in a line of text. This is illustrated in InputTest2.

InputTest2.java

package test;

import java.util.Scanner;

public class InputTest2 {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		while (true) {
			System.out.print("Enter Some Text ('z' to exit):");
			String str = scanner.nextLine();
			System.out.println("You just entered:" + str);
			if ("z".equalsIgnoreCase(str)) {
				System.out.println("Bye!");
				break;
			}
		}
	}
}

The execution of InputTest2 is shown below.

As you can see, I'm getting sleepy. Also, this class uses 'z' as the exit character rather than 'x'.

If you're using Java 6 (or later), you may want to consider using the Console API. It can simplify writing console applications. Using the Console, you can read in a line of text via the following.

Console console = System.console();
String something = console.readLine("Type something: ");

In addition, you can use C-style printf's for text formatting of output to the console. You can also use a Scanner in conjunction with a Console to accept other input types.

Scanner scanner = new Scanner(console.reader());

Since this tutorial is created using Java 1.5, I did not create a test class for the Console API.

We have covered three different methods for obtaining text input in a console application. The first method relied on Readers, the second method utilized the Scanner class, and the third method mentioned used the Java 6 Console class.