JAVA题解 | #整数与IP地址间的转换#

字符串与2进制互相转换,比较易于理解的一种方法

import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            String s1 = sc.nextLine();
            String s2 = sc.nextLine();
            String[] strs = s1.split("\\.");
            StringBuilder sb = new StringBuilder();
            for(int i = 0;i<strs.length;i++)
            {
                int n = Integer.parseInt(strs[i]);
                String binary = Integer.toBinaryString(n);
                int len = binary.length();
                for(int j = 0;j<8-len;j++){
                    binary = '0'+binary;
                }
                sb.append(binary);
            }
            long res1 = Long.parseLong(sb.toString(),2);
            System.out.println(res1);
            String s = Long.toBinaryString(Long.parseLong(s2));
            int len = s.length();
            for(int i = 0;i<32-len;i++){
                s = '0'+s;
            }
            StringBuilder sb2 = new StringBuilder();
            for(int i = 0;i<32;i=i+8){
                String sub = s.substring(i,i+8);
                int n = Integer.parseInt(sub,2);
                sb2.append(n+".");
            }
            String res2 = sb2.toString().substring(0,sb2.length()-1);
            System.out.println(res2);
        }
    }
}