递归方法

public static void main(String[] args) {
    System.out.println("please input a string of Characters:");
    Scanner input=new Scanner(System.in);
    String str=input.nextLine();
    input.close();
    int n=0;
    int m=str.length()-1;
    //boolean p= huiWen(str,n,m);
    if(huiWen(str,n,m))
    System.out.println("这个字符串是回文字符串");
    else
    System.out.println("这个字符串不是回文字符串");
    }
    
    public static boolean huiWen(String str,int n,int m){
        if(n > m)
            throw new IllegalArgumentException();
        if(n == m)
            return true;
        else{
            return (str.charAt(n) == str.charAt(m)) && huiWen(str,n+1,m-1);
        }


    }