isip.java

判断手动键盘输入的IP地址是不是在172.0.0.1到192.168.255.255之间的java小程序

package practice;

import java.util.*;

class  IsAnIp{
	public void  IsAnIpconfig() {
		int count_dian=0;
		
		Scanner in = new Scanner(System.in);
		System.out.println("键入IP地址！：");
		String ipnumber = in.next();
		
		

		for (int i = 0; i < ipnumber.length(); i++) {
			char dian = ipnumber.charAt(i);
			if (dian == '.' )
				count_dian++;
		}
		if(count_dian != 3){  
			System.out.println("这不是一个合法的IP地址！");
		}
		
		String dian0 = "\\.";
		String[] str = ipnumber.split(dian0);
		
		
		int num0 = Integer.parseInt(str[0], 10);
		int num1 = Integer.parseInt(str[1], 10);
		int num2 = Integer.parseInt(str[2], 10);
		int num3 = Integer.parseInt(str[3], 10);
		
		
		if ((num0 >= 172 && num0 <= 191) && (num1 >= 0 && num1 <= 255)
				&& (num2 >= 0 && num2 <= 255) && (num3 >= 0 && num3 <= 255)) {
			System.out.println(ipnumber);
			System.out.println("这是一个合法的IP地址！");

			if ((num0 == 192) && (num1 >= 0 && num1 <= 168)
					&& (num2 >= 0 && num2 <= 255) && (num3 >= 0 && num3 <= 255)) {
				System.out.println(ipnumber);
				System.out.println("这是一个合法的IP地址！");
			}
		} else
			System.out.println("这不是一个合法的IP地址！");

		System.out.println();

	}
		
	

}

public class IsIP {
	public static void main (String[] args){
		IsAnIp p = new IsAnIp();
		p.IsAnIpconfig();
	}
}