java 輸入一個字符串,打印出該字符串中字符的所有排列

import java.util.Scanner;
  
public class Demo001 {
      
    public static void main(String[] args) {
        String str = "";
          
        Scanner scan = new Scanner(System.in);
          
        str = scan.nextLine();
          
        permutation(str.toCharArray(), 0);
    }
  
    public static void permutation(char[] str, int i) {
        if (i >= str.length)
            return;
        if (i == str.length - 1) {
            System.out.println(String.valueOf(str));
        } else {
            for (int j = i; j < str.length; j++) {
                char temp = str[j];
                str[j] = str[i];
                str[i] = temp;
  
                permutation(str, i + 1);
  
                temp = str[j];
                str[j] = str[i];
                str[i] = temp;
            }
        }
    }
  
}