使用字符生成器的reverse功能的会问字符串的检测

import java.util.Scanner;//使用字符生成器的reverse功能的会问字符串的检测
public class PalindromeIgnoreNonAlphanumeric {

public static void main(String[] args)
{
Scanner input=new Scanner(System.in);
System.out.print("Enter a string : ");
String s = input.nextLine();
System.out.println("Ignoring nonalphanumeric characters, \nis "+s+" a palindrome? "+isPalindrome(s));
}
public static boolean isPalindrome(String s)
{
String s1=filter(s);
String s2=reverse(s1);
return s2.equals(s1);
}
public static String reverse(String s)
{
StringBuilder stringBuilder=new StringBuilder(s);
stringBuilder.reverse();//字符生成器 有reverse功能
return stringBuilder.toString();
}
public static String filter(String s)
{
StringBuilder stringBuilder=new StringBuilder();
for(int i=0;i<s.length();i++)
{
if(Character.isLetterOrDigit(s.charAt(i)))
stringBuilder.append(s.charAt(i));
}
return stringBuilder.toString();
}
}