Sbuilder.java

package stringUebung;

import java.util.Random;
import java.util.Scanner;

public class Sbuilder {

	public static void main(String[] args) {
		new Sbuilder().start();
	}
	public void start() {
		Scanner sin = new Scanner(System.in);
		int input = 0; String fuellzeichen = null;
		boolean loop = true;
		while(loop) {
			System.out.print("Geben Sie die Anzahl Zeichen des neuen Strings ein: ");
			int p = 0;
			try {
				p = sin.nextInt();
			} finally {
				input = p;
				sin.nextLine();
			}
			System.out.print("Füllzeichen (erster Character wird benutzt): ");			
			if((fuellzeichen = sin.nextLine()).isEmpty()) {
				System.out.println(this.getRandString(p));
			} else {
				System.out.println(this.getIteratedString(p, fuellzeichen));
			}
		}
	}
	private String getRandString(int length) {
		String _availchars = "abcdefghijklmnopqrstuvwxyz";
		char[] _chars = (_availchars.toUpperCase() + _availchars.toLowerCase()).toCharArray();
		StringBuilder sb = new StringBuilder();
		for(int i : new int[length]) {
			sb.append(Character.toString(_chars[new Random().nextInt(_chars.length - 1)]));
		}
		return sb.toString();
	}
	private String getIteratedString(int p, String f) {
		StringBuilder sb = new StringBuilder();
		for(int i : new int[p]) {
			sb.append(f.toCharArray()[0]);
		}
		
		return sb.toString();
	}

}