Java split()注意事项

split() 方法根据匹配给定的正则表达式来拆分字符串。
"." "$" " |" 和 "*" 等转义字符，必须得加 "\"
split()使用案例
把10.254.32.26/30转换为10.254.32.24-10.254.32.27
第二种方式更直观

import java.util.Scanner;

public class MaskDecoder {
    private static int[] table={128,64,32,16,8,4,2,1};
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Please input:");
        String[] input = in.next().split("/");
        String[] ip=input[0].split("\.");
        int[] output =new int[4];
        for (int i = 0; i < 4; i++) {
            output[i]=Integer.parseInt(ip[i]);
        }
        int maskNumber=Integer.parseInt(input[1]);
        int quotient=maskNumber/8;
        int remainder=maskNumber%8;
        int maskUnit=0;
        for (int i = 0; i < remainder; i++) {
            maskUnit+=table[i];
        }
        output[quotient]&=maskUnit;
        for (int i = quotient + 1; i < 4; i++) {
            output[i]=0;
        }
        System.out.print(output[0]+"."+output[1]+"."+output[2]+"."+output[3]+"-");
        output[quotient]+=(255-maskUnit);
        for (int i = quotient + 1; i < 4; i++) {
            output[i]=255;
        }
        System.out.println(output[0]+"."+output[1]+"."+output[2]+"."+output[3]);
        in.close();
    }
}