java22-网络编程-Toy模板网

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概述

java是internet上的语言，它从语言级上提供了对网络应用程序的支持
java提供网络类库，可以实现无痛的网络连接，联网的底层细节被隐藏在Java本机安装系统里，由JVM控制
直接或者间接的通过网络协议与其它计算机实现数据交换，进行通讯

网络通信要素

通信地址

IP IntAddress类
端口号
端口号加IP地址组合得出一个网络套接字Socket

import org.junit.Test;

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

public class AddressTest {
    @Test
    public void client(){
        Socket socket = null;
        OutputStream os = null;
        try {
            InetAddress inet1 = InetAddress.getByName("127.0.0.1");
            socket = new Socket(inet1, 8080);
            os = socket.getOutputStream();
            os.write("我是客户端".getBytes());
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if(os!=null){
                try {
                    os.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            if(socket!=null){
                try {
                    socket.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }
    @Test
    public void server(){
        ServerSocket ss = null;
        Socket accept = null;
        InputStream is = null;
        ByteArrayOutputStream bis = null;
        try {
            ss = new ServerSocket(8080);
            accept = ss.accept();
            is = accept.getInputStream();
            bis = new ByteArrayOutputStream();
            byte[] bytes = new byte[5];
            int len;
            while ((len=is.read(bytes)) !=-1){
                bis.write(bytes,0,len);
            }
            System.out.println(bis.toString());
            System.out.println(accept.getInetAddress().getHostAddress());
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if(ss!=null){
                try {
                    ss.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }

            }
            if(accept!=null){
                try {
                    accept.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            if(is!=null){
                try {
                    is.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            if(bis!=null){
                try {
                    bis.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }
}

网络规则

TCP/IP协议
- TCP协议使用前，必须建立TCP连接，形成传输数据通道
- 传输前采用三次握手方式，点对点非常可靠
- 在连接中可以进行大数据传输
- 传输完毕，需释放已建立的连接，效率低
UDP协议
- 将数据，源，目的包装成数据包，不需要建立连接
- 每个数据包大小限制在64K内
- 发动不管对方是否准备好，也不管是否接收到，不可靠
- 可以广播发送
- 发送数据完成不用释放资源，开销小，速度快

import org.junit.Test;

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

public class UDPTest {
    @Test
    // 发送端
    public void sender(){
        DatagramSocket ds = null;
        try {
            ds = new DatagramSocket();
            String str = "我是UDP方式发送的导弹";
            byte[] bytes = str.getBytes();
            InetAddress localHost = InetAddress.getLocalHost();
            DatagramPacket dp = new DatagramPacket(bytes, 0, bytes.length, localHost, 8080);
            ds.send(dp);
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if(ds!=null){
                ds.close();
            }
        }
    }
    @Test
    // 接受端
    public void receiver(){
        DatagramSocket ds = null;
        try {
            ds = new DatagramSocket(8080);
            byte[] bytes = new byte[100];
            DatagramPacket dp = new DatagramPacket(bytes, 0, bytes.length);
            ds.receive(dp);
            System.out.println(new String(dp.getData(),0,dp.getLength()));
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            if(ds!=null){
				ds.close();
            }
        }
    }
}

URL类

统一资源定位符，它表示Internet上某一资源的位置
<传输协议>://<主机>:<端口号>/<文件名>#片段名?参数列表

import org.junit.Test;

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

public class URLTest {
    @Test
    public void test(){
        URL url = null;
        try {
            url = new URL("http://localhost:8080/test/test.txt?text=123");
        } catch (MalformedURLException e) {
            throw new RuntimeException(e);
        }
        // 获取URL的协议名
        System.out.println(url.getProtocol());
        // http

        // 获取URL的主机名
        System.out.println(url.getHost());
        // localhost

        // 获取URL的端口号
        System.out.println(url.getPort());
        //8080

        // 获取URL的文件路径
        System.out.println(url.getPath());
        // /test/test.txt

        // 获取URL的文件名
        System.out.println(url.getFile());
        // /test/test.txt?text=123

        // 获取URL的查询名
        System.out.println(url.getQuery());
        // text=123


    }
}

多线程服务端

客户端可以在任意时刻发送请求，而服务端必须时刻准备为客服端的请求提供反馈文章来源地址https://www.toymoban.com/news/detail-628768.html

// 创建多线程服务处理
import java.io.*;
import java.net.Socket;

public class ServerThread extends Thread{
    Socket s = null;
    public ServerThread(Socket s){
        this.s = s;
    }
    @Override
    public void run() {
        InputStream is = null;
        ObjectInputStream ois = null;
        OutputStream os = null;
        DataOutputStream dos = null;
       try {
           is = s.getInputStream();
           ois = new ObjectInputStream(is);
           User user = (User) ois.readObject();
           boolean flag = false;
           if(user.getName().equals("xiaoming")&&user.getPsw().equals("123")){
               flag = true;
           }

           os = s.getOutputStream();
           dos = new DataOutputStream(os);
           dos.writeBoolean(flag);
       } catch (IOException e) {
           throw new RuntimeException(e);
       } catch (ClassNotFoundException e) {
           throw new RuntimeException(e);
       }finally {
           try {
               dos.close();
               os.close();
               ois.close();
               is.close();
           } catch (IOException e) {
               throw new RuntimeException(e);
           }
       }

    }
}

// 服务端代码
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class testServe {
    public static void main(String[] args) throws Exception {
        System.out.println("服务端启动成功");
        ServerSocket ss = new ServerSocket(8080);
        int count = 0;
        // 等待信息
        while (true){
            Socket s = ss.accept();
            new ServerThread(s).start();
            count++;
            System.out.println("接收第"+count+"个信息，ID为"+s.getInetAddress());
        }
    }
}

// 客户端代码
import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
import java.util.Scanner;

public class TestClient {
    public static void main(String[] args) throws Exception {
        InetAddress inet1 = InetAddress.getByName("127.0.0.1");
        Socket so = new Socket(inet1, 8080);
        Scanner scanner = new Scanner(System.in);
        System.out.println("输入账号");
        String name = scanner.next();
        System.out.println("输入密码");
        String pws = scanner.next();
        User user = new User(name,pws);

        OutputStream os = so.getOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(os);
        oos.writeObject(user);

        InputStream is = so.getInputStream();
        DataInputStream dis = new DataInputStream(is);
        boolean b = dis.readBoolean();
        if(b){
            System.out.println("成功");
        }else {
            System.out.println("失败");
        }

        dis.close();
        is.close();
        oos.close();
        os.close();
        so.close();

    }
}