1.遞迴實現

    public static String reverse(String original){
        if(original==null|| original.length()<=1)
            return original;
        return reverse(original.substring(1))+original.charAt(0);
    }

2.String的一些方法

public class test{
 public static void main(String[] args) {
  Scanner input = new Scanner(System.in);
  System.out.print("請輸入：");
  String s1 = input.nextLine();//得到輸入的字串
  System.out.print("翻轉後：");
  for(int i=s1.length()-1;i>=0;i--){
//charAt()返回指定索引處的 char 值。索引範圍為從 0 到 length() - 1
   System.out.print(s1.charAt(i));
  }
 }
}
或者
import java.util.*;
public class StringChange{
    public static void main(String[] args){
     System.out.println("Please enter the String:");
     String str = new Scanner(System.in).nextLine(); //輸入字串
     String s2[] = str.split("\\s");   //  \s  以空格為分隔符拆分字串,並儲存到陣列s2裡面
     for (int i = s2.length-1; i >= 0; i--) {  //反向輸出陣列
         System.out.print(s2[i]+" "); 
     }
  }
}
 

3.利用StringBuffer的內建reverse方法

    public static String reverse2(String s){
		String str;
		StringBuffer sbBuffer =new StringBuffer(s);
		str=sbBuffer.reverse().toString();
		return str;
	}