用StringBuilder来实现经典的反转问题

import java.util.Scanner;

public class Practise03 {

    public static void main(String[] args) {
        //键盘录入一个字符串,用方法进行反转
        System.out.println("请输入一个字符串:");
        Scanner sc = new Scanner(System.in);
        String str = sc.next();

        System.out.println("反转后的字符是:"+reverse(str));
    }

    public static String reverse(String str){
        //经典反转四步骤
        StringBuilder sb = new StringBuilder();
        sb.append(str);
        sb.reverse();
        return sb.toString();
    }

}