[网络协议]JAVA网络编程 【子】

IP： InetAddress

• 唯一定位网络上的计算机
• 127.0.0.1? ? ? ? 本机localhost
• ip地址分类? IPV4/IPV6

1. IPV4? ? ? ? 4个字节（0~255）共42亿? ? ? ? 110.242.69.7
2. IPV6? ? ? ? 128位16字节 8个无符号整数? ? ?fd6d:a06a:4864:0:6de5:84a5:ce7:de56

• ip地址分类? 互联网——局域网

1. 局域网? ? ? ? 128.168.x.x
2. ABCD类? ? A:1.0.0.0---127.255.255.255(1677_7214台)? ?B:128.0.0.0---191.255.255.255（6万多台）C:192.0.0.0---223.255.255.255(254台)? D:224.0.0.0---239.255.255.255

• InetAddress inetAddress0 = InetAddress.getByName("www.bilibili.com");查询网站ip地址

• InetAddress inetAddress2 = InetAddress.getLocalHost();获取本机ip地址

• 常用方法：inetaddress.getCanonicalHostName() 【规范名字】? ? ?inetaddress.getHostAddress()【ip】 inetaddress.getHostName()【域名】

package hk.tcp_udp_url.lesson1;
import java.net.InetAddress;
import java.net.UnknownHostException;
public class InetAddress1 {
    public static void main(String[] args) {
        try{
            InetAddress inetAddress = InetAddress.getByName("127.0.0.1");
            System.out.println(inetAddress);

            InetAddress inetAddress0 = InetAddress.getByName("www.bilibili.com");
            System.out.println(inetAddress0);
        }catch (UnknownHostException e){
            e.printStackTrace();
        }
    }
}

1. ?

?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
• TCP,UDP: 端口号0~65535? ? ? ? ? ? ? 单个协议下端口号不能冲突? ? ? ? ? ? ? ? ? ? ? ? 65535*2? ? ?
• ?端口分类

1. 共有端口? ? ?0~1023? ? ? ? ? ?尽量不要占用?????????????????????????????????????????????????????
   1. ?HTTP:80
   2. HTTPS:443? ? ? ?
   3. FTP:21? ? ? ? ? T
   4. elent:23????????????????????????
2. 程序注册端口：2014~49151
   • Tomcat：8080
   • MySQL:3306
   • Oracle:1521
3. 动态，私有? ? ? ? ? 49152~65535
   • cmd查看所有端口命令

     • netstat -nao

   • ?查看指定端口

     • netstat -nao|findstr "xxx"

       

   • ?查看指定端口进程

     • tasklist|findstr "xxx"

       

4. ?InetSocketAddress

System.out.println(inetSocketAddress.getPort());//端口
System.out.println(inetSocketAddress.getHostName());//ip地址

package hk.tcp_udp_url.lesson1;

import java.net.InetSocketAddress;

public class Lesson2 {

    public static void main(String[] args) {

        InetSocketAddress inetSocketAddress = new InetSocketAddress("127.0.0.1", 8080);

        System.out.println(inetSocketAddress);
        System.out.println(inetSocketAddress.getAddress());
        System.out.println(inetSocketAddress.getPort());//端口
        System.out.println(inetSocketAddress.getHostName());//ip地址
    }
}

?通信协议

TCP/IP协议簇? ? ? ? 一组协议

TCP:用户传输协议? ? ? ? ? ? ? ? 需要连接才能发送? ? ? ? 三次握手；四次挥手

UDP:用户数据报协议? ? ? ? ? ? ?不用连接就能发送（DDos攻击）

TCP 通信：

客户端：

1.? ? ? ? 获取地址，端口；连接服务器socket????????

socket = new Socket(byName【地址】,port【端口】);

2.? ? ? ? 发送消息

outputStream = socket.getOutputStream();
outputStream.write("你好，连接成功了吗？".getBytes(StandardCharsets.UTF_8));

package hk.tcp_udp_url.TCP.deom1;

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.nio.charset.StandardCharsets;


public class Client {
    public static void main(String[] args) {
        Socket socket =null;
        OutputStream outputStream =null;
        try {
            //获取地址
            InetAddress byName = InetAddress.getByName("127.0.0.1");
            //端口
            int port =9999;
            //创建端口socket连接
            socket = new Socket(byName,port);
            //发送消息
            outputStream = socket.getOutputStream();
            outputStream.write("你好，连接成功了吗？".getBytes(StandardCharsets.UTF_8));
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if (outputStream!=null){
                try {
                    outputStream.close();
                }catch (IOException e){
                    e.printStackTrace();
                }
            }if (socket!=null){
                try {
                    socket.close();
                }catch (IOException e){
                    e.printStackTrace();
                }
            }
        }
    }
}

服务端：

1.? ? ? ? 建立端口ServerSocket

2.? ? ? ? 等待客户端连接accept

3.? ? ? ? 接收信息inputStream

package hk.tcp_udp_url.TCP.deom1;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) {

        ServerSocket serverSocket =null;
        Socket socket=null;
        InputStream inputStream =null;
        ByteArrayOutputStream byteArrayOutputStream =null;
        try {
            //创建地址
            serverSocket = new ServerSocket(9999);
            while (true){
                //等待客户端连接
                socket=serverSocket.accept();
                //读取客户端信息
                inputStream = socket.getInputStream();
                //管道流
                byteArrayOutputStream = new ByteArrayOutputStream();
                byte[] buffer=new byte[1024];
                int len;
                while((len=inputStream.read(buffer))!=-1){
                    byteArrayOutputStream.write(buffer,0,len);
                }

                System.out.println(byteArrayOutputStream.toString());
            }
        }catch (IOException e){
            e.printStackTrace();
        }finally {
            //关闭流
            //后创建的先关闭
            if (byteArrayOutputStream!=null){
                try {
                    byteArrayOutputStream.close();
                }catch (IOException e){
                    e.printStackTrace();
                }
            }if (inputStream!=null){
                try {
                    inputStream.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();
                }
            }
        }


    }
}

TCP:? ? ? ? 传文件

服务端

{

    public static void main(String[] args) {
        ServerSocket serverSocket =null;
        Socket accept =null;
        InputStream inputStream =null;
        FileOutputStream fileOutputStream =null;
        try {
            //创建地址
            serverSocket = new ServerSocket(9611);
            //等待客户连接
            accept = serverSocket.accept();
            //读取输入流
            inputStream = accept.getInputStream();
            //管道输出流
            fileOutputStream = new FileOutputStream(new File("C:\\Users\\hk\\Desktop\\002.jpg"));
            byte[] bytes = new byte[1024];
            int len;
            while((len=inputStream.read(bytes))!=-1){
                fileOutputStream.write(bytes,0,len);
            }
            //通知客户端接收完毕
            OutputStream outputStream = accept.getOutputStream();
            outputStream.write("接收完毕，可以断开".getBytes(StandardCharsets.UTF_8));

            //关闭资源
            serverSocket.close();
            accept.close();
            inputStream.close();
            fileOutputStream.close();
        }catch (IOException e) {
            e.printStackTrace();
        }


    }
}

客户端

package hk.tcp_udp_url.TCP.file;

import java.io.*;
import java.net.InetAddress;
import java.net.Socket;

public class Client1 {
    public static void main(String[] args) throws Exception{
        //连接服务器socket
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9611);
        //创建一个输出流
        OutputStream outputStream = socket.getOutputStream();
        //读取文件
        FileInputStream fileInputStream = new FileInputStream(new File("C:\\Users\\hk\\Desktop\\《火影忍者》九只尾兽4k壁纸图片.jpg"));
        //写出文件
        byte[] bytes = new byte[1024];
        int len;
        while ((len=fileInputStream.read(bytes))!=-1){
            outputStream.write(bytes,0,len);
        }
        //终断输出流
        socket.shutdownOutput();
        //确定服务端接收完毕
        InputStream inputStream = socket.getInputStream();
        //管道流接收
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        byte[] bytes1 = new byte[1024];
        int len1;
        while((len1=inputStream.read(bytes1))!=-1){
            byteArrayOutputStream.write(bytes1,0,len1);
        }
        System.out.println(byteArrayOutputStream.toString());
        //关闭资源
        inputStream.close();
        byteArrayOutputStream.close();
        fileInputStream.close();
        outputStream.close();
        socket.close();
    }

UDP? ? ? ? ? ? ? ? 不用连接，只需地址

udp发送消息

?发送端

package hk.tcp_udp_url.udp.deom1;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.nio.charset.StandardCharsets;

public class Client {
    public static void main(String[] args) throws Exception{
        //建立个Socket
        DatagramSocket datagramSocket = new DatagramSocket();
        //建包
        String msg="Hello,world";
        InetAddress localhost = InetAddress.getByName("localhost");
        int port=12900;
        DatagramPacket datagramPacket = new DatagramPacket(msg.getBytes(StandardCharsets.UTF_8),0,msg.getBytes().length,localhost,port);
        //发送包
        datagramSocket.send(datagramPacket);

        datagramSocket.close();
    }
}

接收端?

package hk.tcp_udp_url.udp.deom1;

import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class Server {

    public static void main(String[] args) throws Exception{
        //开放端口
        DatagramSocket datagramSocket = new DatagramSocket(12900);
        //接收包
        byte[] bytes = new byte[1024];
        DatagramPacket datagramPacket = new DatagramPacket(bytes, 0, bytes.length);
        datagramSocket.receive(datagramPacket);//阻塞接收

        System.out.println(datagramPacket.getAddress().getHostAddress());
        System.out.println(new String(datagramPacket.getData(),0,datagramPacket.getData().length));
        //关闭连接
        datagramSocket.close();
    }
}

单方向连续发送信息

发送方

package hk.tcp_udp_url.udp.deom2;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.nio.charset.StandardCharsets;

public class Sender {

    public static void main(String[] args) throws Exception {

        DatagramSocket datagramSocket = new DatagramSocket(19000);
        //从system.in读取数据
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

        while(true){
            String data= bufferedReader.readLine();
            byte[] datas=data.getBytes(StandardCharsets.UTF_8);
            DatagramPacket datagramPacket = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",7922));

            datagramSocket.send(datagramPacket);
            if (data.equals("拜拜")){
                break;
            }
        }

        datagramSocket.close();
    }
}

接收方

package hk.tcp_udp_url.udp.deom2;

import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class Receive {

    public static void main(String[] args) throws  Exception {
        DatagramSocket datagramSocket = new DatagramSocket(7922);

        while (true) {
            //接收信息
            byte[] bytes = new byte[1024];
            DatagramPacket datagramPacket = new DatagramPacket(bytes, 0, bytes.length);
            datagramSocket.receive(datagramPacket);

            //断开判断  “拜拜”
            byte[] data = datagramPacket.getData();
            String datas = new String(data, 0, datagramPacket.getLength());
            System.out.println(datas);
            if (datas.equals("拜拜")) {
                break;
            }
        }
        datagramSocket.close();
    }
}

UDP? ? ? ? 多线程? ? ? ? 双向通信

package hk.tcp_udp_url.udp.deom3;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class TalkReceive implements Runnable{
    DatagramSocket datagramSocket =null;
    private int port;
    private String msf;

    public TalkReceive(int port,String msf)throws Exception {
        this.port=port;
        this.msf=msf;
        datagramSocket=new DatagramSocket(this.port);
    }

    @Override
    public void run() {
        while(true){
            try {
                //接收信息
                byte[] bytes = new byte[1024];
                DatagramPacket datagramPacket = new DatagramPacket(bytes, 0, bytes.length);
                datagramSocket.receive(datagramPacket);

                //断开判断  “拜拜”
                byte[] data = datagramPacket.getData();
                String datas = new String(data, 0, datagramPacket.getLength());
                System.out.println(msf+" :"+datas);
                if (datas.equals("拜拜")) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        datagramSocket.close();
    }
}

package hk.tcp_udp_url.udp.deom3;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.nio.charset.StandardCharsets;

public class TalkSend implements Runnable{

    DatagramSocket datagramSocket =null;
    BufferedReader bufferedReader =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{
            datagramSocket = new DatagramSocket(fromPort);
            bufferedReader = new BufferedReader(new InputStreamReader(System.in));

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

    @Override
    public void run() {
        while (true){
            try {
                String data= bufferedReader.readLine();
                byte[] datas=data.getBytes(StandardCharsets.UTF_8);
                DatagramPacket datagramPacket = new DatagramPacket(datas,0,datas.length,new InetSocketAddress(this.toIP,this.toPort));

                datagramSocket.send(datagramPacket);
                if (data.equals("拜拜")){
                    break;
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
        datagramSocket.close();
    }
}

package hk.tcp_udp_url.udp.deom3;

public class Talk1 {

    public static void main(String[] args) throws Exception {
        //开启线程
        new Thread(new TalkSend(2291,"127.0.0.1",2223)).start();
        new Thread(new TalkReceive(2222,"P2")).start();
    }
}

package hk.tcp_udp_url.udp.deom3;

public class Talk2 {

    public static void main(String[] args) throws Exception {
        new Thread(new TalkSend(2842,"127.0.0.1",2222)).start();
        new Thread(new TalkReceive(2223,"P1")).start();
    }
}

URL? ? ? ? ? ? ? ? 【爬虫，python方便】

package hk.tcp_udp_url;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

public class URL0 {
    public static void main(String[] args) throws IOException {

        //创建URL类
        URL url = new URL("https://github.com");
        //连接url的HTTP
        HttpURLConnection urlConnection =(HttpURLConnection) url.openConnection();
        InputStream inputStream = urlConnection.getInputStream();

        FileOutputStream urltext = new FileOutputStream("urltext");

        byte[] bytes = new byte[1024];
        int len;
        while ((len=inputStream.read(bytes))!=-1){
            urltext.write(bytes,0,len);
        }
        urltext.close();
        inputStream.close();
        urlConnection.disconnect();//断开连接
    }
}