有String s1, String s2两个字符串，s1="adfg2354"……
有String s1, String s2两个字符串，s1=“adfg2354”；把s1倒转赋值到s2上输出，
不能出现其它变量。 还是动动手吧。不能用reserve

package com.mzb.part4;public class StringReverse {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubString s1 = "adfg2354";String s2 = "";for (int i = s1.length()-1; i >= 0; i--) {s2 += (s1.substring(i)).substring(0, 1);}System.out.println(s2);}}