IP

ip地址：InetAddress

• 唯一定位一台网络上计算机
• 127.0.0.1：本机localhost
• ip地址的分类
  • ipV4 / ipV6
    • IPV4 127.0.0.1，4个字节组成，0-255，42亿~；30亿都在北美，亚洲4亿。2011年就用尽；
    • IPV6 128位，8个无符号整数！

      2001:0bb2:aaaa:0015:0000:0000:1aaa:1312
      

  • 公网（互联网）-私网（局域网）
    • ABCD类地址
    • 192.168.xx.xx,专门给组织内部使用的
• 域名：记忆IP问题！
  • IP：www.jd.com

package com.wang.netStudy;

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

//测试IP
public class TestInetAddress {
    public static void main(String[] args){
        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);

            //常用方法
            //System.out.println(inetAddress2.getAddress());
            System.out.println(inetAddress2.getCanonicalHostName());//规范的
            System.out.println(inetAddress2.getHostAddress());//ip
            System.out.println(inetAddress2.getHostName());//域名，或者自己电脑的名称
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}