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Java基础-网络编程

概念

三要素：ip地址、端口、协议

ip地址

InetAddress：表示Internet协议(IP)地址

  • static InetAddress getByName(String host)
    确定主机名称的IP地址。主机名称可以是机器名称，也可以是IP地址
  • String getHostName() 获取此IP地址的主机名
  • String getHostAddress() 返回文本显示中的IP地址字符串
package network.demo1;

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

public class Test1 {
    public static void main(String[] args) throws UnknownHostException {
        InetAddress address = InetAddress.getByName("LAPTOP");
        String name = address.getHostName();
        String ip = address.getHostAddress();

        System.out.println(address);
        System.out.println(name + ' ' + ip);
    }
}

/**
LAPTOP/192.168.93.1
LAPTOP 192.168.93.1
**/

端口

端口:设备上应用程序的唯一标识
端口号:用两个字节表示的整数，它的取值范围是065535。其中，01023之间的端口号用于一些知名的网络服务和应用，普通的应用程序需要使用1024以上的端口号。如果端口号被另外一个服务或应用所占用，会导致当前程序启动失败

协议

计算机网络中，连接和通信的规则被称为网络通信协议。如TCP/UDP

UDP

UDP协议是一种不可靠的网络协议，它在通信的两端各建立一个Socket对象，但是这两个Socket只是发送，接收数据的对象因此对于基于UDP协议的通信双方而言，没有所谓的客户端和服务器的概念
Java提供了DatagramSocket类作为基于UDP协议的Socket

Client

package network.demo2;

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

public class Client {
    public static void main(String[] args) throws IOException {
        //连接信息
        InetAddress address = InetAddress.getByName("127.0.0.1");
        int port = 6666;
        //创建socket对象
        DatagramSocket socket = new DatagramSocket();

        byte[] bys = "Hello world".getBytes();
        //数据包对象
        DatagramPacket dp = new DatagramPacket(bys, bys.length, address, port);

        //发送数据包
        socket.send(dp);

        socket.close();
    }
}

Server

package network.demo2;

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

public class Server {
    public static void main(String[] args) throws IOException {
        //绑定socket
        DatagramSocket socket = new DatagramSocket(6666);

        byte[] bys = new byte[1024];

        //接收数据包
        DatagramPacket dp = new DatagramPacket(bys, bys.length);

        //接收数据
        socket.receive(dp);

        //解析数据 放入缓存区
        byte[] datas= dp.getData();
        int len = dp.getLength();
        String dataStr = new String(datas, 0, len);
        System.out.println(dataStr);

        //关闭socket
        socket.close();
    }
}

TCP

TCP通信协议是一种可靠的网络协议，它在通信的两端各建立一个Socket对象，从而在通信的两端形成网络虚拟链路,一旦建立了虚拟的网络链路，两端的程序就可以通过虚拟链路进行通信。

Java对基于TCP协议的的网络提供了良好的封装，使用Socket对象来代表两端的通信端口，并通过Socket产生IO流来进行网络通信。

Java为客户端提供了Socket类，为服务器端提供了ServerSocket类。

Client

package network.demo4;

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

public class Client {
    public static void main(String[] args) throws IOException {
        InetAddress ip = InetAddress.getByName("127.0.0.1");
        int port = 6666;
        //绑定socket
        Socket socket = new Socket(ip, port);

        //获取流 写数据
        OutputStream os = socket.getOutputStream();
        os.write("Hello world".getBytes());

        socket.close();
    }
}

Server

package network.demo4;

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

public class Server {
    public static void main(String[] args) throws IOException {
        //绑定socket
        ServerSocket serverSocket = new ServerSocket(6666);

        //监听socket
        Socket socket = serverSocket.accept();

        //获取输入流
        InputStream is = socket.getInputStream();
        byte[] bys = new byte[1024];
        int len = is.read(bys);;
        String data = new String(bys, 0, len);
        System.out.println(data);

        socket.close();
        serverSocket.close();
    }
}

Pracite1

客户端:发送数据，接收服务器反馈

服务器:接收数据，给出反馈

Client

package network.demo5;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 6666);

        OutputStream os = socket.getOutputStream();
        os.write("hello".getBytes());

        InputStream is = socket.getInputStream();
        byte[] bys = new byte[1024];
        int len = is.read(bys);
        String data =new String(bys, 0, len);
        System.out.println(data);

        is.close();
        os.close();
        socket.close();
    }
}

Server

package network.demo5;

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

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(6666);

        Socket socket = serverSocket.accept();

        InputStream is = socket.getInputStream();
        byte[] bys = new byte[1024];
        int len = is.read(bys);
        String data = new String(bys, 0, len);
        System.out.println(data);

        OutputStream os = socket.getOutputStream();
        os.write(("大写：" + data.toUpperCase()).getBytes());
    }
}

Pracite2

客户端:数据来自于键盘录入，直到输入的数据是quit，发送数据结束服务器:接收到的数据在控制台输出

Clinet

package network.demo6;

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

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 6666);

        //键盘输入 输入流
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        //封装输出流对象  字节输出流->字符输出流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
        String line;
        while ((line= br.readLine()) != null){
            if ("quit".equals(line)){
                break;
            }
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        socket.close();
    }
}

Server

package network.demo6;

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

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(6666);

        Socket socket = serverSocket.accept();

/*        InputStream is = socket.getInputStream();
        InputStreamReader isr = new InputStreamReader(is);
        BufferedReader br = new BufferedReader(isr);*/

        BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        String line;
        while ((line=br.readLine()) != null){
            System.out.println(line);
        }

        //释放资源
        serverSocket.close();
    }
}

Pracite3

客户端:数据来自于键盘录入，直到输入的数据是quit，发送数据结束服务器:接收到的数据写入文本文件

Client

package network.demo7;

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

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 6666);

        //键盘输入 输入流
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        //封装输出流对象  字节输出流->字符输出流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
        String line;
        while ((line= br.readLine()) != null){
            if ("quit".equals(line)){
                break;
            }
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        socket.close();
    }
}

Server

package network.demo7;

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

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(6666);

        Socket socket = serverSocket.accept();

        //接收数据
        BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        //把数据写入文件
        BufferedWriter bw = new BufferedWriter(new FileWriter("tcp.txt"));
        String line;
        while ((line = br.readLine()) != null){
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        bw.close();
        serverSocket.close();
    }
}

Pracite4

客户端:数据来自于文本文件
服务器:接收到的数据写入文本文件

Client

package network.demo8;

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

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 6666);

        //键盘输入 输入流
        BufferedReader br = new BufferedReader(new FileReader("client.java"));
        //封装输出流对象  字节输出流->字符输出流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
        String line;
        while ((line= br.readLine()) != null){
            bw.write(line);
            bw.newLine();
            bw.flush();
        }
        socket.close();
    }
}

Server

package network.demo8;

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

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(6666);

        Socket socket = serverSocket.accept();

        //接收数据
        BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        //把数据写入文件
        BufferedWriter bw = new BufferedWriter(new FileWriter("server.java"));
        String line;
        while ((line = br.readLine()) != null){
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        bw.close();
        serverSocket.close();
    }
}

Pratice5

客户端:数据来自于文本文件，接收服务器反馈
服务器:接收到的数据写入文本文件，给出反馈，代码用线程进行封装，为每一个客户端开启一个线程

Client

package network.demo10;

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

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 6666);

        //键盘输入 输入流
        BufferedReader br = new BufferedReader(new FileReader("client.java"));
        //封装输出流对象  字节输出流->字符输出流
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
        String line;
        while ((line= br.readLine()) != null){
            bw.write(line);
            bw.newLine();
            bw.flush();
        }

        //设置结束接收信号
        socket.shutdownOutput();

        BufferedReader brStr = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        System.out.println(brStr.readLine());

        socket.close();
    }
}

Server

package network.demo10;

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

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(6666);

        while (true){
            Socket socket = serverSocket.accept();
            new Thread(new ServerThread(socket)).start();
        }
    }
}

ServerThread

package network.demo10;

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

public class ServerThread implements Runnable {
    private Socket socket;

    public ServerThread(Socket socket) {
        this.socket = socket;
    }

    @Override
    public void run() {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            int nums = 0;
            File file = new File("Server[" + nums + "].java");
            while (file.exists()){
                nums++;
                file = new File("Server[" + nums + "].java");
            }
            BufferedWriter bw = new BufferedWriter(new FileWriter(file));

            String line;
            while ((line = br.readLine()) != null){
                bw.write(line);
                bw.newLine();
                bw.flush();
            }

            BufferedWriter bwStr = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
            bwStr.write("文件上传成功");
            bwStr.newLine();
            bwStr.flush();

        }catch (IOException e){
            e.printStackTrace();
        }
    }
}
posted @ 2021-08-09 14:40  Th0r  阅读(44)  评论(0)  编辑  收藏  举报