判斷一個字符串中的字符是否都出現在另一個字符串中（HashSet實現）

import java.util.HashSet;
import java.util.Scanner;

public class StringCompare {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            boolean resultFlag = true;
            String str1 = sc.next();
            String str2 = sc.next();
            HashSet<Character> hs = new HashSet<Character>();
            for (int i = 0; i < str1.length(); i++) {
                hs.add(str1.charAt(i));
            }
            for (int i = 0; i < str2.length(); i++) {
                if (!hs.contains(str2.charAt(i))) {
                    resultFlag = false;
                    break;
                }
            }
            System.out.println(resultFlag);
        }
    }
}

看別人寫的與或操作的完全看不懂，以後再研究下
https://www.cnblogs.com/xkfz007/archive/2012/02/03/2337247.html