合法IP

package com.exam.hw;import java.util.Scanner;public class Main {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubScanner scan =new Scanner(System.in);System.out.println(legalIp(scan.nextLine()));}public static String legalIp(String ip) {// TODO Auto-generated method stubip=ip.trim();if(ip.matches("\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}")){String[] ipArr=ip.split("\\.");int ip1=Integer.parseInt(ipArr[0]);int ip2=Integer.parseInt(ipArr[1]);int ip3=Integer.parseInt(ipArr[2]);int ip4=Integer.parseInt(ipArr[3]);if(ip1<=0 || ip1>=224 ||ip1==127 || ip2<0 || ip2>255 ||    ip3<0 || ip3>255 || ip4<0 || ip4>255  )return "NO";if(ip1>=1&&ip1<=126){if(ip2==ip3&&ip3==ip4){if(ip2==0||ip2==255)return "NO";elsereturn "YES";}else{return "YES";}}else if(ip1>=128 && ip1<=191){if(ip3==ip4){if(ip3==0 || ip3==255)return "NO";elsereturn "YES";}else{return "YES";}}else{if(ip4==0||ip4==255)return "NO";elsereturn "YES";}}else     return"NO"; }}