6-网络编程实战讲解【狂神】

网络通信的两个要素

1、通信双方地址：IP，端口号
2、规则：网络通信协议

IP地址

Ip地址：InetAddress
12.0.0.1 :本机localhost
ipv6:128h

package Internet;

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

//测试IP
public class TestInetAddress {
    public static void main(String[] args) throws UnknownHostException {
        //没有构造器，所以不能实例化，直接调用静态方法
        try {
            //查询本机地址
            InetAddress inetAddress = InetAddress.getLocalHost();
            System.out.println(inetAddress);
            InetAddress inetAddress2 = InetAddress.getByName("127.0.0.1");
            System.out.println(inetAddress2);
            InetAddress inetAddress3 = InetAddress.getByName("localhost");
            System.out.println(inetAddress3);
            //查询域名地址
            InetAddress inetAddress1 = InetAddress.getByName("www.baidu.com");
            System.out.println(inetAddress1);
            //常用方法

            System.out.println(inetAddress1.getCanonicalHostName());
            System.out.println(inetAddress1.getHostAddress());
            System.out.println(inetAddress1.getHostName());


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

    }

}
//Jeff/192.168.1.193
///127.0.0.1
//localhost/127.0.0.1
//183.240.98.161
//183.240.98.161
//www.baidu.comwww.baidu.com/183.240.98.161

端口port

端口表示计算机上的一个程序进程
1、不同的进程有不同的端口号，用来区分软件
2、被规定0-65535
3、TCP，UDP，单个协议下，端口号不能冲突，TCP80，UDP也能用80
端口分类
--公有端口0-1023
http:80
https:443
FTP:21
telent:23
--程序注册端口：1024-49141
tomcat:8080
mysql:3306
oracle：1521
--动态，私有：49152-65535
命令行
netstat -ano#查看所有的端口
netstat-ano |findstr"5900"#查看指定的端口

package Internet;

import java.net.InetSocketAddress;

public class TestInetSocketAddress {
    public static void main(String[] args) {
        InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1", 8080);
        System.out.println(socketAddress);
        System.out.println(socketAddress.getAddress());//127.0.0.1
        System.out.println(socketAddress.getPort());//8080
    }
}

通信协议

协议：约定，就是我们之间用普通话
网络通信协议：速率、传输码率、代码结构 ，传输控制。。。非常复杂
大事化小：分层，只关注分层
TCP/IP协议层
重要：
-TCP：用户传输协议
-UDP：用户数据协议

TCP UDP对比
--TCP打电话
连接，稳定
三次握手，四次挥手
客户端，服务端
传输完成，释放连接，效率低

--UDP：发短信
不连接，不稳定
客户端、服务端，或客户对客户
导弹
DDOS攻击
不管有没准备好，都可以发给你

TCP实现聊天

客户端
1、连接服务器socket
2、发送消息
服务器
1、建立服务的商品ServerSocket
2、等待用户的连接 accept
3、接收用户消息

package Internet;

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

//服务端
public class TcpServerDemo01 {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;
        Socket socket = null;
        InputStream is = null;
        ByteArrayOutputStream baos = null;
        try{
            //我得有一个地址
            serverSocket = new ServerSocket(9999);
            while(true){
                //等待客户端连接过来
                socket = serverSocket.accept();//这个Socket就是客户端的Socket
                //读取客户端发送过来的信息
                is = socket.getInputStream();
                //管道流，对接输入流和输出流，对数据进行包装，使用数据不乱码
                baos = new ByteArrayOutputStream();
                byte[] bytes = new byte[1024];
                int len;
                while ((len = is.read(bytes)) != -1) {
                    baos.write(bytes, 0, len);
                }
                System.out.println(baos.toString());
            }

        }catch (IOException e){
            e.printStackTrace();
        }finally {
            //关闭资源
            if (baos != null) {
                try {
                    baos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (baos != null){
                 try {
                     is.close();
                  } catch (IOException e) {
                        e.printStackTrace();
                 }
           }
            if (baos != null) {
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (baos != null) {
                try {
                    serverSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

package Internet;

import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

//客户端
public class TcpClientDemo02 {
    public static void main(String[] args) {
        Socket socket = null;
        OutputStream os = null;


        try {
            // 获取服务器IP地址
            InetAddress serverIP = InetAddress.getByName("127.0.0.1");
            //端口号
            int port = 9999;

            socket = new Socket(serverIP, port);
            // 发送消息 IO流
            os = socket.getOutputStream();
            os.write("你好，欢迎学习JAVA".getBytes());



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

        }finally {
                if (os != null) {
                    try {
                    os.close();
                }catch (Exception e) {
                    e.printStackTrace();
                }
            }
            if (socket != null) {
                try {
                    socket.close();
                }catch (Exception e) {
                e.printStackTrace();}
            }
        }
    }
}

TCP文件上传

package Internet;
//服务端
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

public class TcpServer03 {
    public static void main(String[] args) throws IOException {
        //创建服务
        ServerSocket serverSocket = new ServerSocket(9000);
        //监听客户端的连接

        Socket socket = serverSocket.accept();//阻塞式监听，会一直等待客户端连接

        //获取输入流
        InputStream is = socket.getInputStream();

        //文件输出
        FileOutputStream fos = new FileOutputStream(new File("receive.jpg"));
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = is.read(buffer))!= -1) {
            fos.write(buffer, 0, len);
        }

        //通知客户端我接收完毕了
        OutputStream os = socket.getOutputStream();
        os.write("接收完毕".getBytes());

        fos.close();
        is.close();
        socket.close();
        serverSocket.close();
    }
}

package Internet;
//客户端
import java.io.*;
import java.net.InetAddress;
import java.net.Socket;

public class TcpClientDemo03 {
    public static void main(String[] args) throws IOException {
        //创建一个socket连接
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
        //创建一个输出流
        OutputStream os = socket.getOutputStream();
        //读取文件
        FileInputStream fis = new FileInputStream(new File("C:\\Users\\60237\\IdeaProjects\\untitled\\src\\OIP-C.jpg"));
        //写出文件
        byte[] buf = new byte[1024];
        int len;
        while ((len = fis.read(buf)) != -1) {
            os.write(buf, 0, len);
        }
        //通知服务器，我已经结束 了
        socket.shutdownOutput();

        //一般还要确定服务器接收完毕，才能断开连接
        InputStream inputStream = socket.getInputStream();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buf1 = new byte[2014];
        int len1;
        while ((len1 = inputStream.read(buf1)) != -1) {
            baos.write(buf1, 0, len1);
        }
        System.out.println(baos.toString());

        //关闭流
        os.close();
        fis.close();
        socket.close();
    }

}

UDP消息发送

发短信，不用连接，需要知道对方地址
发送端和接收端的概念，没有服务器
接收端

package Internet;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
//还是要等待客户端的链接
public class UdpServerDemo01 {
    public static void main(String[] args)throws IOException {
        //开放端口
        DatagramSocket socket = new DatagramSocket(9090);
        //接收数据包
        byte[] buffer = new byte[1024];
        DatagramPacket packet = new DatagramPacket(buffer, 0,buffer.length);
        socket.receive(packet);
        System.out.println(packet.getAddress().getHostAddress());
        System.out.println(packet.getData().length);
        //关闭连接
        socket.close();
    }
}

发送端

package Internet;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

//不需要连接服务器
public class UdpClinetDemo01 {
    public static void main(String[] args)throws Exception {
        //建立一个socket
        DatagramSocket socket = new DatagramSocket();
        //建个包
        String message = "你好呀，服务器";
        //发送给谁
        InetAddress address = InetAddress.getByName("127.0.0.1");
        int port = 9090;
        //数据，数据长度，地址，端口
        DatagramPacket packet = new DatagramPacket(message.getBytes(), 0, message.length(), address, port);
        //发送包
        socket.send(packet);
        //关闭socket
        socket.close();
    }
}

UDP聊天实现

package Internet.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;
import java.util.stream.Stream;

public class UdpSenderDemo0 {
    public static void main(String[] args) throws IOException {
        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", 9999));
            socket.send(packet);
            if (data.equals("exit")) {
                break;
            }
        }

        socket.close();


    }
}

package Internet.chat;

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

public class UdpReceiveDemo01 {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket(9999);


        while(true) {
            // 接收数据报
            byte[] container = new byte[1024];
            DatagramPacket packet = new DatagramPacket(container,0, container.length);
            socket.receive(packet);
            //断开连接
            byte[] data = packet.getData();
            String receiveData = new String(data, 0, packet.getLength());
            System.out.println("接收到的数据：" + receiveData);
            if(receiveData.equals("bye")) {
                break;
            }


        }
        socket.close();

    }
}

UDP多线程在线咨询

一端又能发送又能接收，所以需要双线程

package Internet.chat;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;

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

    }
    @Override
    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("exit")) {
                    break;
                }
            }catch (Exception e) {
                    e.printStackTrace();
            }

        }
        socket.close();

    }
}

package Internet.chat;

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

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 (Exception e) {
            e.printStackTrace();
        }
    }
    @Override
    public void run() {

        while(true) {
            try {
                // 接收数据报
                byte[] container = new byte[1024];
                DatagramPacket packet = new DatagramPacket(container,0, container.length);
                socket.receive(packet);
                //断开连接
                byte[] data = packet.getData();
                String receiveData = new String(data, 0, data.length);
                System.out.println(msgFrom + "说：" + receiveData);
                if(receiveData.equals("bye")) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }



        }
        socket.close();

    }
}

package Internet.chat;

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();
    }
}

package Internet.chat;

public class TalkTeacher {
    //开户两个线程
    public static void main(String[] args) {
        new Thread(new TalkSend(5555, "localhost", 8888)).start();
                new Thread(new TalkReceive(9999, "学生")).start();
    }
}

URL下载网络资源

1、协议：//IP地址：端口/项目名/资源

package Internet;

import java.net.MalformedURLException;
import java.net.URL;

public class URLDemo01 {
    public static void main(String[] args) throws MalformedURLException {
        URL url = new URL("http://localhost:8080/helloworld/index.html?username=admin&password=123456");
        url.getProtocol(); // http
        url.getHost(); // localhost
        url.getPort(); // 8080
        url.getPath(); // /helloworld/index.html
        url.getQuery(); // username=admin&password=123456
    }
}

public class UrlDown {
    public static void main(String[] args) throws IOException {
        //下载地址
        URL url = new URL("https://img-s-msn-com.akamaized.net/tenant/amp/entityid/AA1zDXRZ.img?w=636&h=419&m=6");
        //连接到这个资源http
        java.net.HttpURLConnection httpUrlConnection = (java.net.HttpURLConnection) url.openConnection();
        InputStream inputStream = httpUrlConnection.getInputStream();
        FileOutputStream fos = new FileOutputStream("1111.jpg");
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer))!= -1) {
            fos.write(buffer, 0, length);
            }
        fos.close();
        inputStream.close();
        httpUrlConnection.disconnect();
        System.out.println("下载完成");
    }
}