网络编程-IP-2022-12-14

IP 唯一定位网络上一台计算机

127.0.0.1    本机 local Host  

IP地址的分类

  1、IPV4  127.0.0.1 由四个字节组成 0-255   42亿个  30亿在北美  4亿 亚洲   2011用尽

        IPV6  2409:8a20:e3c:43e0:4524:c9fb:bfec:77a1     128位  8个无符号整数

 

    2、公网（互联网）、私网 （局域网）

         192.168.XX.XX       局域网，给组织内部使用的

域名：记忆IP问题  www.vip.com 

   

package com.lr;

import java.net.InetAddress;
import java.net.UnknownHostException;

public class webTest {
    public static void main(String[] args) {
        // Ctrl+Alt+T
        try {
            //查询本机地址
            InetAddress inetAddress1 = InetAddress.getByName("127.0.0.1");
            System.out.println(inetAddress1);
            InetAddress inetAddress3 = InetAddress.getByName("localhost");
            System.out.println(inetAddress3);
            InetAddress inetAddress4 = InetAddress.getLocalHost();
            System.out.println(inetAddress4);

            //查询网站IP地址
            InetAddress inetAddress2 = InetAddress.getByName("www.baidu.com");
            System.out.println(inetAddress2);

            System.out.println("--------------------------------------------------------");

            System.out.println(inetAddress2.getAddress());
            System.out.println(inetAddress2.getHostAddress());       //IP
            System.out.println(inetAddress2.getCanonicalHostName());
            System.out.println(inetAddress2.getHostName());          // 域名或者自己电脑名字

        } catch (UnknownHostException e) {
            throw new RuntimeException(e);
        }
    }
}