zoukankan      html  css  js  c++  java
  • 初识网络编程(1)

    一、网络编程
    计算机网络:
    是指将地理位置不同的具有独立功能的多台计算机及其外部设备通过线路连接起来,在网络操作系统,网络管理软件及网络通信协议的管理和协调下,实现资源共享和信息传递的计算机系统

    网络编程的目的:
    无线电台。。。广播交流信息。数据交换。通信
    想要达到这个效果需要什么:
    1.如何准确的定位网络上的一台主机。(ip地址+端口,定位到这个计算机上的某个资源)
    2.找到了这个主机,如何传输数据呢?

    1.2网络通信的要素
    如何实现网络的通信?
    通信双方地址:

    • ip
    • 端口号
    • 192.168.16.124:5900
      规则:网络通信的协议
      TCP/IP参考模型:
      在这里插入图片描述

    小结:
    1.网络编程中有两个主要的问题

    • 如何准确的定位到网络上的一台或者多台主机
    • 找到主机之后如何进行通信
      2.网络编程中的要素
    • IP和端口号
    • 网络通信协议

    3.万物皆对象

    1.3、IP
    ip地址:
    唯一定位一台网络计算机
    127.0.0.1:本机localhsot
    IP地址分类:

    • ipv4/ipv6
    • IPV4 127.0.0.1,四个字节组成。4个字节
    • IPV6 fe80::1d13:3045:4c25:c508%17,128位

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

    1.4端口
    端口表示计算机上的一个程序进程;
    不同的进程有不同的端口号!用来区分软件!
    被规定0~65535
    TCP,UDP:65535*2 单个协议下,端口号不能冲突
    端口分类
    公有端口0~1023
    HTTP:80
    HTTPS:443
    FTP:21
    Telent:23
    程序注册端口:1024~49151分配各用户或者程序
    Tomcat:8080
    MySQL:3306
    Oracle:1521
    动态、私有:49152-65535

    netstat -ano #查看所有端口
    netstat -ano|findstr "5900"
    
    ctrl+shift+esc 打开任务管理器
    windows+e	打开我的电脑
    
    package com.kiki.lession01;
    
    import java.net.InetSocketAddress;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 9:54
     */
    //套接字
    public class TestInetScoketAddress {
    
        public static void main(String[] args) {
            InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1", 8080);
            InetSocketAddress localhostAddress = new InetSocketAddress("localhost", 8080);
            System.out.println(socketAddress);
            System.out.println(localhostAddress);
            System.out.println("===========================");
            System.out.println(socketAddress.getAddress());
            System.out.println(socketAddress.getHostName());
            System.out.println(socketAddress.getPort());
    
        }
    }
    输出:
    /127.0.0.1:8080
    localhost/127.0.0.1:8080
    ===========================
    /127.0.0.1
    eureka01
    8080
    
    

    1.5通信协议
    协议:约定
    **网络通信协议:**速率、传输码率、代码结构、传输控制…
    TCP/IP协议簇
    重要:
    TCP:用户传输协议
    UDP:用户数据报协议
    出名的协议:
    TCP:
    IP:网络互连协议

    TCP和UDP对比:
    TCP:打电话

    • 连接,稳定

    • 三次握手,四次挥手

    最少需要三次,保证稳定连接!
    A:你愁啥?
    B:瞅你咋地?
    A:干一场?

    A:我要走了
    B:真的要走了吗?
    B:你真的真的要走了吗?
    A:我真的要走了。

    • 客户端、服务端

    UDP:发短信
    不连接、不稳定
    客户端、服务器:没有明确的界限
    不管有没有准备好,都可以发给你。

    1.6、TCP
    客户端:
    1.连接服务器Socket
    2.发送消息

    package com.kiki.lession02;
    
    import java.io.IOException;
    import java.io.OutputStream;
    import java.net.InetAddress;
    import java.net.Socket;
    import java.net.UnknownHostException;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 11:20
     */
    //客户端
    public class TcpClientDemo01 {
        public static void main(String[] args) {
            Socket socket = null;
            OutputStream os = null;
            try {
                //1.要知道服务器的地址,端口号
                InetAddress serverIP = InetAddress.getByName("127.0.0.1");
                int port = 9999;
                //2.创建一个Scoket连接
                socket = new Socket(serverIP,port);
                //3.发送消息,IO流
                os = socket.getOutputStream();
                os.write("你好,欢迎学习kiki".getBytes());
    
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                if (os != null){
                    try {
                        os.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
    
                if (socket != null){
                    try {
                        socket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
    
    
        }
    }
    
    
    

    服务器:
    1.建立服务的端口 ServerSocket
    2.等待用户的连接 accept
    3.接收用户的消息

    package com.kiki.lession02;
    
    import java.io.ByteArrayOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 11:21
     */
    //服务端
    public class TcpServerDemo01 {
        public static void main(String[] args) {
    
            ServerSocket serverSocket =null;
            Socket socket =null;
            InputStream is =null;
            try {
                //1.我得有一个地址
                serverSocket = new ServerSocket(9999);
                //2.等待客户端连接过来
                //返回的socket就是客户端连接过来的socket
                socket = serverSocket.accept();
                //3.读取客户端的消息
                is = socket.getInputStream();
    
                //管道流
                System.out.println(getMessageByChannelStream(is));
    
    
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                if (is != null){
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (socket != null){
                    try {
                        socket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (serverSocket != null){
                    try {
                        serverSocket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
    
            }
        }
    
        public static String getMessage(InputStream is){
            byte[] buffer = new byte[1024];
            int len;
            try {
                while ((len=(is.read(buffer)))!=-1){
                    String msg = new String(buffer, 0, len);
                    System.out.println(msg);
                    return msg;
                }
    
            } catch (IOException e) {
                e.printStackTrace();
            }
    
            return null;
        }
    
        public static String getMessageByChannelStream(InputStream is){
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int len;
    
            try {
                while ((len=(is.read(buffer)))!=-1){
                    baos.write(buffer,0,len);
                }
                return baos.toString();
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                if (baos != null){
                    try {
                        baos.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
    
            return null;
        }
    }
    
    

    文件上传
    客户端

    package com.kiki.lession03;
    
    import java.io.*;
    import java.net.InetAddress;
    import java.net.Socket;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 13:39
     */
    public class TcpClientDemo02 {
        public static void main(String[] args) throws Exception{
            //1.创建一个socket连接
            Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
            //2.创建一个输出流
            OutputStream os = socket.getOutputStream();
            //3.文件流,读取文件
            //E:kikistudayes-studyspringboot-08-shirokiki-network1.jpg
            FileInputStream fis = new FileInputStream(new File("1.jpg"));//针对于项目的相对路径
            //4.写出文件
            byte[] buffer = new byte[1024];
            int len;
            while ((len=fis.read(buffer))!=-1){
                os.write(buffer,0,len);
            }
    
    
            //通知服务器,我已经传输完了
            socket.shutdownOutput();//我已经传输完了
    
    
            //确定服务器接收完毕,才能够断开连接
            InputStream sis = socket.getInputStream();
            //返回String byte[] 类型数组 通过管道流
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] receiveBuffer = new byte[1024];
            int receiveLen;
            while ((receiveLen=(sis.read(receiveBuffer)))!=-1){
                 baos.write(receiveBuffer,0,receiveLen);
            }
            System.out.println(baos.toString());
            //5.关闭资源
            baos.close();
            sis.close();
            fis.close();
            os.close();
            socket.close();
    
        }
    
    }
    
    

    服务器端

    package com.kiki.lession03;
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.net.ServerSocket;
    import java.net.Socket;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 13:40
     */
    public class TcpServerDemo02 {
        public static void main(String[] args) throws Exception{
            //1.创建服务
            ServerSocket serverSocket = new ServerSocket(9000);
            //2.监听客户端的连接
            Socket socket =  serverSocket.accept();//阻塞式监听,会一直等待客户端的连接
            //3.获取输入流
            InputStream is = socket.getInputStream();//is就是我们接收图片(文件流)
            //4.管道输出流
            FileOutputStream fos = new FileOutputStream(new File("receive.jpg"));
            byte[] buffer = new byte[1024];
            int len;
            while ((len=is.read(buffer))!=-1){
                fos.write(buffer,0,len);
            }
    
            //通知客户端我接收完毕了
            OutputStream ops = socket.getOutputStream();
            ops.write("我接收完毕了,你可以断开了".getBytes());
    
            fos.close();
            is.close();
            socket.close();
            serverSocket.close();
        }
    }
    
    
    

    1.7、UDP
    发短信:不用连接,需要知道对方的地址!
    发送端

    package com.kiki.lession04;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetAddress;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 15:11
     */
    //UDP不需要连接服务器
    public class UdpClientDemo01 {
        public static void main(String[] args) throws Exception{
            //1.建立一个socket
            DatagramSocket socket = new DatagramSocket();
            //2.建个包
            String msg = "你好啊,服务器";
            //发送给谁
            InetAddress localhost = InetAddress.getByName("localhost");
            int port = 9090;
            /**
             *  @param   buf      the packet data.  数据
             *  @param   offset   the packet data offset.   数据的长度起始
             *  @param   length   the packet data length.   长度
             *  @param   address  the destination address.  要发送给谁
             *  @param   port     the destination port number.
             */
            DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.getBytes().length, localhost, port);
            //3.发送包
            socket.send(packet);
    
            //4.关闭流
            socket.close();
        }
    }
    
    
    

    接收端

    package com.kiki.lession04;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 15:25
     */
    //等待客户端的连接
    public class UdpSereverDemo01 {
        public static void main(String[] args) throws Exception{
            //1.开放端口
            DatagramSocket socket = new DatagramSocket(9090);
            //2.接收数据包
            byte[] buffer = new byte[1024];
            DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
    
            socket.receive(packet);//阻塞接收
            System.out.println("[kki-info:]"+packet.getAddress().getHostAddress());
            System.out.println(new String(packet.getData(),0,packet.getLength()));
            //关闭连接
            socket.close();
    
    
        }
    }
    
    
    

    咨询:发送消息

    package com.kiki.chat;
    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetSocketAddress;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 15:46
     */
    public class UdpSenderDemo01 {
        public static void main(String[] args) throws Exception{
    
            DatagramSocket socket = new DatagramSocket(8888);
            //准备数据:控制台读取System.in
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
            while (true){
                String data = reader.readLine();
                byte[] datas = data.getBytes();
                DatagramPacket packet = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",6666));
                socket.send(packet);
                if (data.equals("bye")){
                    break;
                }
            }
    
    
            socket.close();
        }
    }
    
    

    接收消息

    package com.kiki.chat;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 15:46
     */
    public class UdpReceiveDemo01 {
        public static void main(String[] args) throws Exception{
            DatagramSocket socket = new DatagramSocket(6666);
    
            //准备接收包裹
            while (true){
                byte[] container = new byte[1024];
                DatagramPacket packet = new DatagramPacket(container,0,container.length);
                socket.receive(packet);//阻塞式接收包裹
    
                //断开连接 bye
                byte[] data = packet.getData();
                String receiveData = new String(data, 0, data.length);
                System.out.println("[kiki-debug]=>"+receiveData);
                if (receiveData.equals("bye")){
                    break;
                }
            }
    
            socket.close();
    
        }
    }
    
    
    

    在线咨询:两个人都可以是发送方,也可以都是接收方
    TalkSend

    package com.kiki.chat;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetSocketAddress;
    import java.net.SocketException;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 16:30
     */
    public class TalkSend implements Runnable{
        DatagramSocket socket = null;
        BufferedReader reader = null;
    
        private int fromPort;
        private String toIP;
        private int toPort;
    
        public TalkSend(int fromPort,String toIP,int toPort){
            this.fromPort = fromPort;
            this.toIP = toIP;
            this.toPort = toPort;
            try {
                socket = new DatagramSocket(fromPort);
                //准备数据:控制台读取System.in
                reader = new BufferedReader(new InputStreamReader(System.in));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        public void run() {
    
            while (true){
                try {
                    String data = reader.readLine();
                    byte[] datas = data.getBytes();
                    DatagramPacket packet = new DatagramPacket(datas,0,datas.length,new InetSocketAddress(this.toIP,this.toPort));
                    socket.send(packet);
                    if (data.equals("bye")){
                        break;
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            socket.close();
        }
    }
    
    
    

    TalkReceive

    package com.kiki.chat;
    
    import java.io.IOException;
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.SocketException;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 17:07
     */
    public class TalkReceive implements Runnable{
    
        DatagramSocket socket = null;
        private int port;
        private String msgFrom;
    
        public TalkReceive(int port,String msgFrom){
            this.port = port;
            this.msgFrom = msgFrom;
            try {
                socket = new DatagramSocket(port);
            } catch (SocketException e) {
                e.printStackTrace();
            }
        }
    
        public void run() {
            while (true){
                try {
                    //准备接收包裹
                    byte[] container = new byte[1024];
                    DatagramPacket packet = new DatagramPacket(container,0,container.length);
                    socket.receive(packet);//阻塞式接收包裹
                    //断开连接 bye
                    byte[] data = packet.getData();
                    String receiveData = new String(data, 0, data.length);
                    System.out.println(msgFrom+":[kiki-debug]=>"+receiveData);
                    if (receiveData.equals("bye")){
                        break;
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
    
            socket.close();
        }
    }
    
    

    TalkStudent

    package com.kiki.chat;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 17:19
     */
    //既可以是接收端,也可以是发送端
    public class TalkStudent {
        public static void main(String[] args) {
            //开启两个线程
            new Thread(new TalkSend(7777,"localhost",9999)).start();
            new Thread(new TalkReceive(8888,"老师")).start();
        }
    }
    
    
    
    

    TalkTeacher

    package com.kiki.chat;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/8 17:25
     */
    public class TalkTeacher {
    
        public static void main(String[] args) {
            //开启两个线程
            new Thread(new TalkSend(5555,"localhost",8888)).start();
            new Thread(new TalkReceive(9999,"学生")).start();
        }
    
    }
    
    
    
    

    1.8、URL
    https://www.baidu.com/
    统一资源定位符:定位资源的,定位互联网上的某一个资源
    DNS域名解析:www.baidu.com

    协议://ip地址:端口号/项目名/资源

    下载网络资源:

    package com.kiki.lession05;
    
    import java.io.FileOutputStream;
    import java.io.InputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
    
    /**
     * @author kiki
     * @version 1.0
     * @create 2020/8/9 9:06
     */
    public class URLDown {
        public static void main(String[] args) throws Exception{
            //1.下载地址
            //下载网络资源
            //https://win-web-nf01-sycdn.kuwo.cn/c1c548ac6ee4b1d0b1c51a4cb5d839dc/5f2f5164/resource/n2/31/39/366999325.mp3
            URL url = new URL("https://win-web-nf01-sycdn.kuwo.cn/c1c548ac6ee4b1d0b1c51a4cb5d839dc/5f2f5164/resource/n2/31/39/366999325.mp3");
    
            //2.连接到这个资源 HTTP
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
    
            InputStream inputStream = urlConnection.getInputStream();
    
            FileOutputStream fos = new FileOutputStream("bucengtingguodecengjing.mp3");
    
            byte[] buffer = new byte[1024];
            int len;
            while ((len=inputStream.read(buffer))!=-1){
                fos.write(buffer,0,len);//写出这个数据
            }
    
            fos.close();
            inputStream.close();
            urlConnection.disconnect();
        }
    }
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
  • 相关阅读:
    Problem C: 类的初体验(V)
    接口与继承
    类和对象
    java函数方法
    数组
    string类的一些函数方法
    java语法基础
    大道至简——做个懒人
    java编程 求和
    编程的精义
  • 原文地址:https://www.cnblogs.com/kiki-study/p/13656091.html
Copyright © 2011-2022 走看看