网络编程Day02

通信协议

网络通信协议：速率、传输码率、代码结构、传输控制...

问题：非常的复杂

分层：大事化小

TCP/IP协议簇：实际上是一组协议

TCP：用户传输协议
UDP：用户数据报协议
IP：网络互联协议

TCP UDP对比

TCP：打电话
- 连接，稳定
- 三次握手，四次分手
  
  最少需要三次，保证稳定连接
  
  最少需要四次，保证连接断开
- 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、服务端没有明确的界限
- 不管有没有准备好，都可以发送

TCP

客户端

连接服务器Socket
发送消息

package com.dongfang.ip.lesson02;

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

//客户端
public class TCPClientDemo01 {
    public static void main(String[] args) {

        Socket socket = null;
        OutputStream os = null;

        try {
            //1.要知道服务器的地址，端口号
            InetAddress serverIP = InetAddress.getByName("127.0.0.1");
            int port = 9999;
            //2.创建一个socket连接
            socket = new Socket(serverIP,port);
            //3.发送消息IO流
            os = socket.getOutputStream();
            os.write("你好".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();
                }
            }
        }
    }
}

服务器

建立服务器端口ServerSocket
等待用户的连接accept
接收用户的消息

package com.dongfang.ip.lesson02;

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) {
        ServerSocket serverSocket = null;
        Socket socket = null;
        InputStream is = null;
        ByteArrayOutputStream baos = null;

        try {
            //1.得有一个地址
            serverSocket = new ServerSocket(9999);
            //2.等待客户端连接过来
            socket = serverSocket.accept();//同一个socket
            //3.读取客户端的消息
            is = socket.getInputStream();

            /*
            byte[] buffer = new byte[1024];
            int len;
            while ((len = is.read(buffer)) != -1){
                String msg = new String(buffer, 0, len);
                System.out.println(msg);
            }
            */

            //管道流
            baos = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int len;
            while ((len = is.read(buffer)) != -1){
                baos.write(buffer,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 (is != null){
                try {
                    is.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();
                }
            }
        }
    }
}

文件上传

客户端

package com.dongfang.ip.lesson02;

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

public class TCPClientDemo02 {
    public static void main(String[] args) throws Exception {
        //1.创建一个Socket连接
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
        //2.创建一个输出流
        OutputStream os = socket.getOutputStream();

        //3.读取文件
        FileInputStream fis = new FileInputStream(new File("food_big.jpg"));
        //4.写出文件
        byte[] buffer = new byte[1024];
        int len;
        while ((len = fis.read(buffer)) != -1) {
            os.write(buffer,0,len);
        }

        //通知服务器已经传输完毕
        socket.shutdownOutput();

        //确定服务器接收完毕才能够断开连接
        InputStream is = socket.getInputStream();
        //String byte[]
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer2 = new byte[1024];
        int len2;
        while ((len2 = is.read(buffer2)) != -1) {
            baos.write(buffer2,0,len2);
        }
        System.out.println(baos.toString());

        //5.关闭资源
        baos.close();
        fis.close();
        os.close();
        is.close();
        socket.close();
    }
}

服务器端

package com.dongfang.ip.lesson02;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class TCPServerDemo02 {
    public static void main(String[] args) throws Exception {
        //1.创建服务
        ServerSocket serverSocket = new ServerSocket(9000);
        //2.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
        //3.获取输入流
        InputStream is = socket.getInputStream();
        //4.文件输出
        FileOutputStream fos = new FileOutputStream(new File("receive.jpg"));
        byte[] buffer = new byte[1024];
        int len;
        while ((len = is.read(buffer)) != -1){
            fos.write(buffer,0,len);
        }

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

        //5.关闭资源
        fos.close();
        is.close();
        serverSocket.close();
        socket.close();
    }
}

Tomcat

服务端

自定义 S
Tomcat服务器 S ：Java后台开发

客户端

自定义 C
浏览器 B

UDP

不用连接，但是需要知道对方的地址

发送端

package com.dongfang.ip.lesson03;

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

//不需要连接服务器
public class UDPClientDemo01 {
    public static void main(String[] args) throws Exception {
        //1.建立一个Socket
        DatagramSocket socket = new DatagramSocket();
        //2.建个包
        String msg = "Hello World";
        //发送给谁
        InetAddress localhost = InetAddress.getByName("localhost");
        int port = 9090;
        //数据  数据的起始长度  要发送给谁
        DatagramPacket packet = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);
        //3.发送包
        socket.send(packet);
        //4.关闭流
        socket.close();
    }
}

接收端

package com.dongfang.ip.lesson03;

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

//还是要等待客户端的连接
public class UDPServerDemo01 {
    public static void main(String[] args) throws Exception {
        //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);//接收

        socket.receive(packet);//阻塞接收

        System.out.println(packet.getAddress().getHostAddress());
        System.out.println(new String(packet.getData(),0,packet.getLength()));
        //关闭连接
        socket.close();
    }
}

UDP聊天

循环发送消息

package com.dongfang.ip.chat;

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

public class UDPSenderDemo01 {
    public static void main(String[] args) throws Exception {

        DatagramSocket socket = new DatagramSocket(8888);

        //准备数据：控制台读取System.in
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        String data = reader.readLine();
        byte[] datas = data.getBytes();
        DatagramPacket packet = new DatagramPacket(datas,0,datas.length,new InetSocketAddress("localhost",6666));

        socket.send(packet);

        socket.close();
    }
}

循环接收消息

import java.net.DatagramSocket;

public class UDPReceiveDemo01 {
    public static void main(String[] args) throws Exception {
        DatagramSocket socket = new DatagramSocket(6666);

        while (true){
            //准备接收包
            byte[] container = new byte[1024];
            DatagramPacket packet = new DatagramPacket(container,0,container.length);
            socket.receive(packet);//阻塞式接收包

            //断开连接  bye
            byte[] data = packet.getData();
            String receiveData = new String(data, 0, packet.getLength());
            System.out.println(receiveData);
            if (receiveData.equals("bye")){
                break;
            }
        }
        socket.close();
    }
}

两个人都可以是发送方和接收方

URL

统一资源定位符：定位互联网上的某一个资源

协议://ip地址:端口/项目名/资源

package com.dongfang.ip.lesson04;

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.jsp?username=dongfangyulv&password=123");
        
        System.out.println(url.getProtocol());//协议
        System.out.println(url.getHost());//主机IP
        System.out.println(url.getPort());//端口
        System.out.println(url.getPath());//文件
        System.out.println(url.getFile());//全路径
        System.out.println(url.getQuery());//参数
    }
}

package com.dongfang.ip.lesson04;

import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class URLDown {
    public static void main(String[] args) throws Exception{
        //1.下载地址
        URL url = new URL("http://localhost:8080/dongfangyulv/SecurityFile.txt");

        //连接到这个资源  HTTP
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

        InputStream inputStream = urlConnection.getInputStream();

        FileOutputStream fos = new FileOutputStream("SecurityFile.txt");

        byte[] buffer = new byte[1024];
        int len;
        while ((len = inputStream.read(buffer)) != 1){
            fos.write(buffer,0,len);//写出这个数据
        }
        fos.close();
        inputStream.close();
        urlConnection.disconnect();//断开连接
    }
}

posted on 2024-09-29 20:24 东方语虑阅读(19) 评论(0) 收藏举报