[网络协议]网络编程入门

1 本章重点

本章重点有:

1 网络传输三要素

2Tcp和udp区别

3tcp三次握手

4 tcp和udp 传输文件

2 本章学习注意

会用到多线程，字符串API，IO流等知识，前面的学不会，后面的也难学

3 udp传输

udp传输服务器先后开无所谓

1 InetAddress

public class InterAdderess {
    public static void main(String[] args) throws UnknownHostException {
        //封装了域名的基本信息
        InetAddress b1 = InetAddress.getByName("www.acfun.cn");
        System.out.println(b1);
        System.out.println("----------------------");
        String hostAddress = b1.getHostAddress();
        String name = b1.getHostName();
        //获得ip地址
        System.out.println(hostAddress);
        //获得网址名字-主机名
        System.out.println(name);
    }
}

2? udp传输基本

发送端

public class Send {
    public static void main(String[] args) throws Exception {
        //创建发送用对象
        DatagramSocket ds=new DatagramSocket();
        //创建包裹信息
        //DatagramPacket(byte buf[], int length, InetAddress address, int port)
        byte[] bytes = "得国之正者惟汉与明".getBytes();
        int length = bytes.length;
        InetAddress ip = InetAddress.getByName("192.168.0.192");
        int port=10088;
        DatagramPacket dp=new DatagramPacket(bytes,length,ip,port);
        //发送
        ds.send(dp);
        //关闭
        ds.close();
    }

}

接受端

public class ReceiveDemo {
    public static void main(String[] args) throws Exception {
        //创建socket对象
        DatagramSocket ds=new DatagramSocket(10088);
        //创建接受容器
        byte[] b1=new byte[1048576];
        int length = b1.length;
        DatagramPacket dp=new DatagramPacket(b1,length);


        //存储接收器对象
        ds.receive(dp);
        //解析数据包
        //获得缓冲区
        byte[] data = dp.getData();
        //获得长度
        int length1 = dp.getLength();
        //获得解析后数据
        String s=new String(data,0,length1);
        //获得ip
        InetAddress address = dp.getAddress();
        String ip=address.getHostAddress();

        System.out.println(ip+":"+s);
        //释放资源
        ds.close();
    }
}

?3 UDP键盘录入接受数据

客户端

public class Send {
    public static void main(String[] args) throws Exception {
        //创建发送用对象
        DatagramSocket ds=new DatagramSocket();
        //创建包裹信息
        //DatagramPacket(byte buf[], int length, InetAddress address, int port)
        Scanner sc=new Scanner(System.in);
        String s=null;
        while (true){
            s=sc.next();
            while (s.equals("886")){
                //关闭
                ds.close();
                System.exit(0);
            }
            byte[] bytes = s.getBytes();
            int length = bytes.length;
            InetAddress ip = InetAddress.getByName("192.168.0.192");
            int port=10088;
            DatagramPacket dp=new DatagramPacket(bytes,length,ip,port);
            //发送
            ds.send(dp);
        }
    }
}

接收端

public class ReceiveDemo {
    public static void main(String[] args) throws Exception {
        //创建socket对象
        DatagramSocket ds=new DatagramSocket(10088);
        while (true){
            //创建接受容器
            byte[] b1=new byte[1048576];
            int length = b1.length;
            DatagramPacket dp=new DatagramPacket(b1,length);
            //存储接收器对象
            ds.receive(dp);
            //解析数据包
            //获得缓冲区
            byte[] data = dp.getData();
            //获得长度
            int length1 = dp.getLength();
            //获得解析后数据
            String s=new String(data,0,length1);
            //获得ip
            InetAddress address = dp.getAddress();
            String ip=address.getHostAddress();

            System.out.println(ip+":"+s);
//            //释放资源
//            ds.close();
        }
    }
}

5 多线程开启UDP

主客户端

public class ChatRoom {
    public static void main(String[] args) throws Exception {
        DatagramSocket sendDs=new DatagramSocket();
        DatagramSocket receiveDs=new DatagramSocket(10087);

        SendThread s1=new SendThread(sendDs,10087);
        ReceiveThread r1=new ReceiveThread(receiveDs);

        Thread t1=new Thread(s1);
        Thread t2=new Thread(r1);
        t2.start();
        t1.start();
    }
}

发送

public class SendThread implements Runnable {
    private  DatagramSocket ds;
    private int port;
    public SendThread( DatagramSocket send,int port) {
        this.ds=send;
        this.port=port;
    }

    @Override
    public void run() {
        Scanner sc=new Scanner(System.in);
        String s=null;
        while (true){
            s=sc.next();
            while (s.equals("886")){
                //关闭
                ds.close();
                System.exit(0);
            }
            byte[] bytes = s.getBytes();
            int length = bytes.length;
            InetAddress ip = null;
            try {
                ip = InetAddress.getByName("192.168.0.192");
                DatagramPacket dp=new DatagramPacket(bytes,length,ip,port);
                //发送
                ds.send(dp);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

接收

public class ReceiveThread implements Runnable {
    DatagramSocket rs;

    public ReceiveThread(DatagramSocket rs) {
        this.rs = rs;
    }

    @Override
    public void run() {

        try {
            while (true) {
                //创建接受容器
                byte[] b1 = new byte[1048576];
                DatagramPacket dp = new DatagramPacket(b1, b1.length);
                //存储接收器对象
                rs.receive(dp);
                //解析数据包
                //获得缓冲区
                //获得解析后数据
                String s = new String(dp.getData(), 0, dp.getLength());
                //获得ip
                String ip = dp.getAddress().getHostAddress();

                System.out.println(ip + ":" + s);
//            //释放资源
//            ds.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

4 TCP传输

tcp传输必须先开服务器

1 基本传输

客户端

/**
 * @author 花溪
 * @create 2021-07-15 13:46
 * 1 写socket对象
 * 2 输出流数据
 * 3 释放
 */
public class Client {
    public static void main(String[] args) throws IOException {
        Socket s = new Socket("192.168.0.192", 10876);
        OutputStream outputStream = s.getOutputStream();
        outputStream.write("法国元帅贝当爷爷".getBytes());
        s.close();
    }
}

服务器

/**
 * @author 花溪
 * @create 2021-07-15 13:53
 * 1 创建服务器socket
 * 2 监听
 * 3 读
 * 4 释放
 */
public class ServerDemo {
    public static void main(String[] args) throws IOException {
        ServerSocket s=new ServerSocket(10876);
        Socket ss = s.accept();
        //获取ip和内容
        String ip = ss.getInetAddress().getHostAddress();

        InputStream inputStream = ss.getInputStream();
        byte[] b=new byte[1024];
        int len=inputStream.read(b);
        String s1= new String(b,0,len);
        System.out.println(ip+":"+s1);
        ss.close();
    }
}

2 键盘传输

客户端

/**
 * @author 花溪
 * @create 2021-07-15 19:57
 */
public class Client {
    public static void main(String[] args) throws IOException {
        Socket s=new Socket("192.168.0.192",19999);

        Scanner sc=new Scanner(System.in);


        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
        String ss=null;
        while (true){
            System.out.println("聊点什么？");
            String line=sc.nextLine();
            if(line.equals("886")){
                break;
            }
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        s.close();
    }
}

服务器

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket s=new ServerSocket(19999);
        Socket ss = s.accept();
        BufferedReader is=new BufferedReader(new InputStreamReader(ss.getInputStream()));
        String line=null;
        while ((line=is.readLine())!=null){
            System.out.println(ss.getInetAddress().getHostAddress()+"："+line);
        }
        ss.close();
    }
}

3 提供回复信息

/**
 * @author 花溪
 * @create 2021-07-15 19:39
 * 服务器给反馈
 */
public class TcpServer {
    public static void main(String[] args) throws IOException {
        //创建Socket对象
        ServerSocket s=new ServerSocket(10076);
        //监听对象
        Socket ss = s.accept();
        //读
        InputStream is = ss.getInputStream();
        byte[] bytes=new byte[1024];
        int len=is.read(bytes);
        String server=new String(bytes,0,len);
        String ip = ss.getInetAddress().getHostAddress();
        System.out.println(ip+":"+server);
        //回复数据
        OutputStream outputStream = ss.getOutputStream();
        outputStream.write("你们是虫子".getBytes());
        //关闭
        ss.close();
    }
}

客户端

public class Client {
    public static void main(String[] args) throws IOException {
        //获取socket
        Socket s=new Socket("192.168.0.192",10076);
        //获取输出流
        OutputStream outputStream = s.getOutputStream();
        outputStream.write("烦死啦".getBytes());
        //获取输入流
        InputStream inputStream = s.getInputStream();
        byte[] bytes=new byte[1024];
        int read = inputStream.read(bytes);
        String s1=new String(bytes,0,read);
        System.out.println(s1);
        //释放
        s.close();
    }
}

4 上传图片

客户端

public class UploadClient {
    public static void main(String[] args) throws IOException {
        Socket s=new Socket("192.168.0.192",11111);
//        封装图片
        BufferedInputStream bis=new BufferedInputStream(new FileInputStream("E:\\香缇.png"));
        //封装流
        BufferedOutputStream bos = new BufferedOutputStream(s.getOutputStream());
        //把数据读入流中
        byte[] bys = new byte[1024];
        int len=0;
        while ((len=bis.read(bys))!=-1){
            bos.write(bys,0,len);
            bos.flush();
        }
//        在客户端执行shutdownOutput方法用来表明数据发送完毕，不再发送更多数据。
        s.shutdownOutput();
        //接受反馈
        InputStream inputStream = s.getInputStream();
        byte[] bytes=new byte[1024];
        int len2=inputStream.read(bytes);
        String client = new String(bytes,0,len2);
        System.out.println(client);

        bis.close();
        s.close();

    }
}

服务器

public class UploadServer {
    public static void main(String[] args) throws IOException {
        ServerSocket s=new ServerSocket(11111);
        Socket sss= s.accept();
        BufferedInputStream bs=new BufferedInputStream(sss.getInputStream());
        BufferedOutputStream bf=new BufferedOutputStream(new FileOutputStream("E:\\mmm.png"));
        byte[] bys=new byte[1024];
        int len;
        while ((len=bs.read(bys))!=-1){
            bf.write(bys,0,len);
            bf.flush();
        }
        //反馈
        OutputStream outputStream = sss.getOutputStream();
        outputStream.write("上传图片成功了!".getBytes());
        outputStream.close();
        sss.close();



    }
}

5 包装流上传文本

服务器

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket s=new ServerSocket(9999);
        Socket ss=s.accept();
        BufferedReader br=new BufferedReader(new InputStreamReader(ss.getInputStream()));
        BufferedWriter bw=new BufferedWriter(new FileWriter("e:\\a.txt"));
        String line=null;
        while ((line=br.readLine())!=null){
            System.out.println("读取数据");
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        bw.close();
        ss.close();
    }
}

客户端

public class Clinet {
    public static void main(String[] args) throws IOException {
        File file = new File("E:\\1852铁血中华.txt");

        Socket s=new Socket("192.168.0.192",9999);
        BufferedReader br=new BufferedReader(new FileReader(file));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));
        String line=null;
        while ((line=br.readLine())!=null){
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        s.close();
    }
}