本来不用加预处理preTreate这一步的。 就要
输入:$bo*y gi!r#l
输出:l r gi y bo
乱七八糟的测试应力。

import java.util.Scanner;
public class Main {
    public static void main(String[] args){
        Scanner in  = new Scanner(System.in);
        while(in.hasNextLine()){
            String li = in.nextLine();
            String[] list = preTreate(li).split(" ");
            StringBuilder builder = new StringBuilder();
            for(int i =0 ; i < list.length;i++){
                String tempStr = list[list.length-i-1];
                if(i==0){
                    builder.append(tempStr);
                }else {
                    builder.append(" "+tempStr);
                }
            }
            System.out.println(builder);
        }
    }
    public static String preTreate(String str)
    {
        return  str.replaceAll("[^(a-z|A-Z)]"," ");
    }
}