java 实现发送icmp java发送ip报文

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网络小墨 2024-07-01 16:11:03

文章标签 java 实现发送icmp java System .net 文章分类 Java 后端开发

一、一些概念理解

网络中的包：可以理解为现实中包裹，信封，需要快递员送到我们的手上
丢包：可以理解为包裹在运输途中丢失
单机：无网，没有与其他电脑资源共享
网络编程的目的：无线电台，传播交流信息，数据交换，通信

如何实现网络的通信？

通信双方的地址：

端口号

192.168.16.124：5900

规则：网络通信的协议

TCP/IP参考模型

二、IP

IP地址在 Java.Inet.Address类中
唯一定位一台网络上的计算机
本机 127.0.0.1：localhost
IP地址的分类：
ipv4 / ipv6
公网-私网
域名：记忆IP问题
IP：www.vip.com

import java.net.InetAddress;
import java.net.UnknownHostException;

//测试IP
public class TestInetAddress {
    public static void main(String[] args) {
        try {
            //查询本机地址
            InetAddress inetAddress1 = InetAddress.getByName("127.0.0.1");
            System.out.println(inetAddress1);
            InetAddress inetAddress3 = InetAddress.getByName("localhost");
            System.out.println(inetAddress3);
            InetAddress inetAddress4 = InetAddress.getLocalHost();
            System.out.println(inetAddress4);

            //查询网站ip地址
            InetAddress inetAddress2 = InetAddress.getByName("www.baidu.com");  //www.baidu.com/14.215.177.38
            System.out.println(inetAddress2);

            //常用方法
//            System.out.println(inetAddress2.getAddress());
            System.out.println(inetAddress2.getCanonicalHostName());    //规范的名字
            System.out.println(inetAddress2.getHostAddress());  //ip
            System.out.println(inetAddress2.getHostName()); //域名，或者自己电脑的名字
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

三、端口

端口表示计算机上的一个程序的进程：
不同的进程有不同的端口号，用来区分软件！
被规定 0~65535
TCP，UDP 每个协议都有65535。单个协议下，端口号不能冲突
端口分类：
公有端口 0 ~ 1023：
HTTP：80
HTTPS：443
FTP：21
Telent：23
程序注册端口：1024 ~ 49151，分配用户或者程序
Tomcat：8080
MySql：3306
Oracle：1521

netstat -ano #查看所有的端口
netstat -ano|findstr "5900" #查看指定的端口
tasklist|findstr "8696" #查看指定端口的进程

import java.net.InetSocketAddress;

public class TestInetSocketAddress {
    public static void main(String[] args) {
        InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1", 8080);
        InetSocketAddress socketAddress2 = new InetSocketAddress("localhost", 8080);
        System.out.println(socketAddress);
        System.out.println(socketAddress2);

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

    }
}

四、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：网络互连协议

五、TCP 实现聊天

客户端
1.连接服务器 Socket
2.发送消息

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

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链接
            socket = new Socket(serverIP, port);
            //3.发送消息    IO流
            os = socket.getOutputStream();
            os.write("你好你好".getBytes());
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                os.close();
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

服务端
1.建立服务的端口 ServerSocket
2.等待用户的链接 accept
3.接收用户的消息

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class TcpServerDemo01 {
    public static void main(String[] args) {
        ServerSocket serverSocket = null;
        Socket socket = null;
        InputStream is = null;
        ByteArrayOutputStream baos = null;

        try {
            //1.我得有一个地址
            serverSocket = new ServerSocket(9999);

            while (true){
                //2.等待客户端链接过来
                socket = serverSocket.accept();
                //3.读取客户端的消息
                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 {
            //关闭资源
            try {
                baos.close();
                is.close();
                socket.close();
                serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

六、UDP

//发送端
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.建立个包
        String msg = "服务器";
        //发送给谁
        InetAddress localhost = InetAddress.getByName("localhost");
        int port = 9090;
        //数据，数据的长度起始，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
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);

        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();
    }
}

//发送端
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));

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

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


        socket.close();
    }
}

//学生端
public class TalkStudent {
    public static void main(String[] args) {
        //开启两个线程
        new Thread(new Talksend(7777, "localhost", 9999)).start();
        new Thread(new TalkReceive(8888, "老师")).start();
    }
}

//老师端
public class TalkTeacher {
    public static void main(String[] args) {
        new Thread(new Talksend(5555, "localhost", 8888)).start();
        new Thread(new TalkReceive(9999, "学生")).start();
    }
}

七、URL

Uniform Resource Locator, 统一资源定位器