[网络协议] TCP和UDP网络代码实战

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[网络协议]TCP和UDP网络代码实战

TCP和UDP都是运输层的网络协议

UPD和TCP的区别

区别	UDP	TCP
是否连接	无连接，不连接就可以直接发送数据，所以不可靠	经过三次握手，才建立连接，面向连接
是否可靠	不可靠传输，不使用流量控制和拥塞控制	可靠传输，使用流量控制和拥塞控制
连接对象个数	支持一对一，一对多，多对一和多对多交互通信	只能是一对一通信
传输方式	面向报文	面向字节流
首部开销	首部开销小，仅8字节	首部最小20字节，最大60字节
适用场景	适用于实时应用（IP电话、视频会议、直播等）	适用于要求可靠传输的应用，例如文件传输

使用TCP实现聊天

服务器端
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class tcpserver {

    public static void main(String[] args) throws IOException {
        //有一个地址

        ServerSocket serverSocket  = new ServerSocket(999);

        //等待客户端连接
        Socket socket = serverSocket.accept();

        InputStream inputStream = socket.getInputStream();

        //管道
        ByteArrayOutputStream byteArrayOutputStream =
                new ByteArrayOutputStream();

        byte[] bytes = new byte[1024];
        int len;
        while((len = inputStream.read(bytes))!=-1){
            byteArrayOutputStream.write(bytes,0,len);
        }

        System.out.println(byteArrayOutputStream.toString());



    }
}

客户端

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

public class tcpclient {

    public static void main(String[] args) throws IOException {
        //知道服务器端地址
        InetAddress name = InetAddress.getByName("127.0.0.1");
        int port = 999;

        //创建socket连接
        Socket socket = new Socket(name,port);
//发送消息
        OutputStream outputStream = socket.getOutputStream();


        outputStream.write("您好 我在访问".getBytes());

    }
}

TCP实现文件上传

服务器端：

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

public class tcpFileServer {

    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(999);

        Socket socket = serverSocket.accept();

        InputStream inputStream = socket.getInputStream();

        FileOutputStream fileOutputStream  = new FileOutputStream("receive.png");

        byte[] bytes = new byte[1024];
        int len;
        while((len = inputStream.read(bytes))!=-1){
            fileOutputStream.write(bytes,0,len);
        }
    }
}

客户端：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;

public class tcpFile {

    public static void main(String[] args) throws IOException {
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),999);

        OutputStream outputStream = socket.getOutputStream();

        FileInputStream file = new FileInputStream(new File("/Users/mac/Desktop/springboot/miaokill/Net/liuji.png"));

        byte[] bytes = new byte[1024];

        int len;
        while((len = file.read(bytes))!=-1){
            outputStream.write(bytes);
        }
    }
}

UDP实现聊天

发送端

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.*;

public class UdpChatSend {

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

        DatagramSocket socket = new DatagramSocket(0000);
        BufferedReader bufferedReader =
                new BufferedReader(new InputStreamReader(System.in));

        while (true) {

            String data = bufferedReader.readLine();
            DatagramPacket packet = new DatagramPacket(data.getBytes(), data.getBytes().length
                    , new InetSocketAddress("127.0.0.1", 9898));


            socket.send(packet);
            if(data.equals("bye")){
                break;
            }
        }


        socket.close();

    }
}

接收端

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;

public class UdpChatRecive {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket(9898);
        while (true) {
            byte[] bytes = new byte[1024];


            DatagramPacket packet = new DatagramPacket(bytes, 0,bytes.length
            );
            socket.receive(packet);
            byte[] data = packet.getData();
            String receive = new String(data,0,data.length);
            System.out.println(receive);
            if (receive.equals("bye")) {
                break;
            }



        }
        socket.close();

    }
}

但是这样只能实现一个人发，一个人收，如何实现双方互相发送，就为两者开辟两条线程。

两人互相发送

接收端：

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;

public class ThreadUdpReceive implements Runnable {

    DatagramSocket socket = null;
    private int port;
    private String fromMsg;

    public ThreadUdpReceive(int port, String fromMsg) throws SocketException {
        this.fromMsg = fromMsg;
        this.port = port;
        socket = new DatagramSocket(port);


    }


    @Override
    public void run() {


        while (true) {
            try {
                byte[] bytes = new byte[1024];


                DatagramPacket packet = new DatagramPacket(bytes, 0, bytes.length
                );
                socket.receive(packet);
                byte[] data = packet.getData();
                String receive = new String(data, 0, data.length);
                System.out.println(fromMsg + "：" + receive);
                if (receive.equals("bye")) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }


        }
        socket.close();
    }
}

发送端：

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;

public class ThreadUdpSend implements Runnable {

    DatagramSocket socket = null;
    BufferedReader bufferedReader = null;
    private int fromport;
    private int port;
    private String myip;

    public ThreadUdpSend(int fromport, int port, String myip) throws SocketException {
        this.fromport = fromport;
        this.port = port;
        this.myip = myip;
        socket = new DatagramSocket();
        bufferedReader =
                new BufferedReader(new InputStreamReader(System.in));

    }


    @Override
    public void run() {


        while (true) {

            try {
                String data = bufferedReader.readLine();
                DatagramPacket packet = new DatagramPacket(data.getBytes(), data.getBytes().length
                        , new InetSocketAddress(this.myip, this.port));


                socket.send(packet);
                if (data.equals("bye")) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }


        socket.close();
    }
}

测试：

import java.net.SocketException;

public class StudentSend {
    public static void main(String[] args) throws SocketException {
        new Thread(
                new ThreadUdpSend(7777,9999,"localhost")).start();
        new Thread(new ThreadUdpReceive(8888, "老师")).start();
    }
}




import java.net.SocketException;

public class TeacherSend {
    public static void main(String[] args) throws SocketException {
        new Thread(new ThreadUdpSend(1231, 8888, "localhost")).start();
        new Thread(
                new ThreadUdpReceive(9999, "学生")
        ).start();


    }
}