网络编程

在这里插入图片描述

cmd ping www.baidu.com

IP

127.0.0.1:本机 localhost

ip地址分类

ipv4/ipv6
- ipv4 127.0.0.1 4个字节 ~42亿 2011年已经用尽
- ipv6 240e:b5:4100:3cf3:18b5:1368:bfcd:163 128位 8个无符号整数表示
公网（互联网）-私网（局域网）
- 192.168.xx.xx（专门给组织内部使用的）
- A B C D类地址 0~127 128~192 193~224 225~255

try {
    
    
    //查询本机地址
    InetAddress inetAddress1 = InetAddress.getByName("127.0.0.1");
    System.out.println(inetAddress1);
    InetAddress inetAddress2 = InetAddress.getByName("localhost");
    System.out.println(inetAddress2);
    InetAddress inetAddress3 = InetAddress.getLocalHost();
    System.out.println(inetAddress3);

    //查询百度地址
    InetAddress inetAddress4 = InetAddress.getByName("www.baidu.com");
    System.out.println(inetAddress4);

    //常用方法
    System.out.println(inetAddress4.getAddress());
    System.out.println(inetAddress4.getCanonicalHostName());//规范的名字
    System.out.println(inetAddress4.getHostAddress());//ip
    System.out.println(inetAddress4.getHostName());//域名或者自己电脑的名字
} catch (UnknownHostException e) {
    
    
    e.printStackTrace();
}

端口

netstat -aon//cmd查询所有端口

netstat -ano|findstr “5900” //查看指定端口

tasklist|findstr “8696”//查看指定端口进程

协议

TCP：用户传输协议

UDP：用户数据报协议

TCP UDP对比

TCP：打电话

连接+稳定
三次握手四次分手
- A->B B->A A->B
- A->B B->A B->A A->B
客户端服务端

UDP：发短信

不连接+不稳定
客户端和服务端没有明确界限
不管是否准备好都能发送

InetSocketAddress inetSocketAddress1 = new InetSocketAddress("127.0.0.1", 8080);
InetSocketAddress inetSocketAddress2 = new InetSocketAddress("localhost", 8080);
System.out.println(inetSocketAddress1);
System.out.println(inetSocketAddress2);

System.out.println(inetSocketAddress1.getAddress());
System.out.println(inetSocketAddress1.getHostName());//地址
System.out.println(inetSocketAddress1.getPort());//端口

TCP

服务端

建立服务端口ServerSocket
等待用户连接accept

接受用户消息

package com.Eiso;

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 TcpServer {
      
      
    public static void main(String[] args) {
      
      
        ServerSocket serverSocket = null;
        Socket socket =null;
        InputStream is=null;
        ByteArrayOutputStream baos=null;
        try {
      
      
            //地址9998
            serverSocket = new ServerSocket(9998);
            while(true){
      
      
                //等待客户端连接
                socket = serverSocket.accept();
                //读取客户端消息
                is=socket.getInputStream();
                //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 {
      
      
            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();
                }
            }
        }
    }
}

客户端

连接服务器Socket
发送消息

package com.Eiso;

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

//客户端
public class TcpClient {
    
    
    public static void main(String[] args) {
    
    
        Socket socket = null;
        OutputStream os =null;
        try {
    
    
            //获得服务器地址 端口号
            InetAddress serverIP = InetAddress.getByName("127.0.0.1");
            int port = 9998;
            //创建socket连接
            socket = new Socket(serverIP,9998);
            //发送消息IO流
            os = socket.getOutputStream();
            os.write("cnewclkweckl".getBytes());
        } catch (Exception e) {
    
    
            e.printStackTrace();
        }finally {
    
    
            if(os!=null){
    
    
                try {
    
    
                    os.close();
                } catch (IOException e) {
    
    
                    e.printStackTrace();
                }
            }
            if(socket!=null){
    
    
                try {
    
    
                    socket.close();
                } catch (IOException e) {
    
    
                    e.printStackTrace();
                }
            }

        }
    }
}

文件传输

package com.Eiso;

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

//客户端
public class TcpClient {
    
    
    public static void main(String[] args) throws Exception{
    
    
        //创建socket连接
        Socket socket = new Socket(InetAddress.getByName("127.0.0.1"),9998);
        //创建输出流
        OutputStream os = socket.getOutputStream();
        //读取文件
        FileInputStream fis= new FileInputStream(new File("untitled.jpg"));
        //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
        socket.shutdownOutput();
        //确定
        InputStream inputStream = socket.getInputStream();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        byte[] buffer2 = new byte[2048];
        int len2;
        while((len2=inputStream.read(buffer2))!=-1){
    
    
            baos.write(buffer2,0,len2);
        }
        System.out.println(baos.toString());
        //关闭资源
        baos.close();
        inputStream.close();
        fis.close();
        os.close();
        socket.close();
    }
}

package com.Eiso;

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

//服务端
public class TcpServer {
    
    
    public static void main(String[] args) throws Exception{
    
    
        //创建服务
        ServerSocket serverSocket = new ServerSocket(9998);
        //监听客户端
        Socket socket=serverSocket.accept();
        //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;
        while((len=is.read(buffer))!=-1){
    
    
            fos.write(buffer,0,len);
        }
        //通知客户端
        OutputStream os = socket.getOutputStream();
        os.write("接收成功".getBytes());
        //关闭资源
        fos.close();
        is.close();
        socket.close();
        serverSocket.close();
    }
}

Tomcat

服务端 tomcat

客户端网页

UDP

package com.Eiso;

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

//服务端
public class TcpServer {
    
    
    public static void main(String[] args) throws Exception{
    
    
        //开放端口
        DatagramSocket socket = new DatagramSocket(9998);
        //接受包
        byte[] buffer = new byte[1024];
        DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
        socket.receive(packet);
        System.out.println(new String(packet.getData(),0,packet.getLength()));
        //关闭流
        socket.close();

    }
}

package com.Eiso;

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

//客户端
public class TcpClient {
    
    
    public static void main(String[] args) throws Exception{
    
    
        //建立socket
        DatagramSocket socket = new DatagramSocket();
        //建立包
        String msg = "hello world";
        //发送给谁
        InetAddress localhost = InetAddress.getByName("localhost");
        int port = 9998;

        DatagramPacket packet = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port);
        //发送包
        socket.send(packet);
        //关闭流
        socket.close();
    }
}

UDP聊天

多线程：

package com.Eiso;

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 ID;

    public TalkReceive(int port,String ID){
    
    
        this.port=port;
        this.ID=ID;
        try{
    
    
            socket = new DatagramSocket(port);
        }catch (Exception e){
    
    
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
    
    
        while(true){
    
    
            try {
    
    
                //准备接受
                byte[] buffer = new byte[1024];
                DatagramPacket packet = new DatagramPacket(buffer, 0, buffer.length);
                socket.receive(packet);
                //断开连接
                byte[] data = packet.getData();
                String receiveData = new String(data, 0, data.length);
                System.out.println(ID+":"+receiveData);
                if(receiveData.startsWith("bye")) {
    
    
                    break;
                }
            } catch (Exception e) {
    
    
                e.printStackTrace();
            }
        }
        //关闭流
        socket.close();
    }
}

package com.Eiso;

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);
            reader = new BufferedReader(new InputStreamReader(System.in));
        }catch (Exception e){
    
    
            e.printStackTrace();
        }

    }

    @Override
    public void run() {
    
    
        while(true){
    
    
            try{
    
    
                String data = reader.readLine();
                byte[] msg = data.getBytes();
                DatagramPacket packet = new DatagramPacket(msg,0,msg.length,new InetSocketAddress(this.toIP,this.toPort));
                //发送包
                socket.send(packet);
                if(data.equals("bye")){
    
    
                    break;
                }
            }catch (Exception e){
    
    
                e.printStackTrace();
            }
        }
        socket.close();
    }
}

package com.Eiso;

public class TalkStudent {
    
    
    public static void main(String[] args) {
    
    
        //双线程
        new Thread(new TalkSend(9996,"localhost",9998)).start();
        new Thread(new TalkReceive(9997,"Teacher")).start();
    }
}

package com.Eiso;

public class TalkTeacher {
    
    
    public static void main(String[] args) {
    
    
        //双线程
        new Thread(new TalkSend(9995,"localhost",9997)).start();
        new Thread(new TalkReceive(9998,"Student")).start();
    }
}

URL

统一资源定位符

协议（http）+://+IP地址（www.baidu.com）+:+端口号（8080）+/+项目名+/+资源

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

public class main {
    
    
    public static void main(String[] args) throws Exception {
    
    
        URL url = new URL("http://localhost:8080/helloworld/index.jsp?username=kuangshen&password=123");
        System.out.println(url.getProtocol());//协议
        System.out.println(url.getHost());//IP
        System.out.println(url.getPort());//端口
        System.out.println(url.getPath());//文件
        System.out.println(url.getFile());//文件全路径
        System.out.println(url.getQuery());//参数

        //下载地址
        url = new URL("http://localhost:8080/test/this.txt");
        //连接资源
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        InputStream inputStream = urlConnection.getInputStream();
        FileOutputStream fos = new FileOutputStream("this.txt");
        byte[] buffer = new byte[1024];
        int len;
        while((len=inputStream.read(buffer))!=-1){
    
    
            fos.write(buffer,0,len);//写出数据
        }

        fos.close();
        inputStream.close();
        urlConnection.disconnect();
    }
}
/test/this.txt");
        //连接资源
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        InputStream inputStream = urlConnection.getInputStream();
        FileOutputStream fos = new FileOutputStream("this.txt");
        byte[] buffer = new byte[1024];
        int len;
        while((len=inputStream.read(buffer))!=-1){
    
    
            fos.write(buffer,0,len);//写出数据
        }

        fos.close();
        inputStream.close();
        urlConnection.disconnect();
    }
}

【傲霜凌雪丶】TCP_UDP笔记

网络编程

IP

端口

协议

TCP

文件传输

Tomcat

UDP

UDP聊天

URL

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