java 输入一个字符串,打印出该字符串中字符的所有排列

public class JavaDemo {

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;
        }
    }
}

}