初识网络编程

前言

1.端口表示计算机的一个程序的进程：
2.不同的进程有不同的端口号，用来区分软件
3.理论上规定了0~65536
4.TCP，UDP：65536*2 Tcp：80 udp:80,单个协议下，端口不能冲突
5.端口分类：
    共有端口0~1023
        HTTP:80    超文本传输协议
        HTTPS：443 超文本传输安全协议，基于ssl的http协议
        FTP：21  ，文件传输协议
        Telent：23  远程传输协议
    程序注册端口：1024~49151
        Tomcat：8080
        MySQL：3306
        Oracle：1521
     动态，私有：49152~65535

简单实现网络通信

package com.cl.lesson01;


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

//封装IP，InetAddress
public class TestInterAddress {
    public static void main(String[] args) {
        try {
            InetAddress interAddress1=InetAddress.getByName("127.0.0.1");
            System.out.println(interAddress1);
            InetAddress interAddress3=InetAddress.getByName("localhost");
            System.out.println(interAddress3);
            InetAddress interAddress4=InetAddress.getLocalHost();
            System.out.println(interAddress4);

            //查询网站IP地址
            InetAddress interAddress2=InetAddress.getByName("www.baidu.com");
            System.out.println(interAddress2);

            //常用方法
            System.out.println(interAddress2.getAddress());
            System.out.println(interAddress2.getCanonicalHostName());//规范的名字
            System.out.println(interAddress2.getHostAddress());//ip
            System.out.println(interAddress2.getHostName());//域名

        }catch (UnknownHostException e){
            e.printStackTrace();
        }

    }
}



package com.cl.lesson01;

import java.net.InetSocketAddress;

//封装计算机的ip+端口号，InetSocketAddress
public class TestInetSocketAddress {
    public static void main(String[] args) {

        InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1",8080);
        InetSocketAddress socketAddress2 = new InetSocketAddress("localhost",8080);
        System.out.println(socketAddress2);

        System.out.println(socketAddress.getAddress());
        System.out.println(socketAddress.getHostName());//地址
        System.out.println(socketAddress.getPort());//端口


    }
}