[网络协议]JAVA实现网络客户端和服务端简单通信2（逐渐加深）实现图片的传输

1.创建客户端和服务器

客户端输入正确的用户名和密码，服务端会显示

public class loginClient {


    public static void main(String[] args) throws IOException {
        while(true){
            Socket socket = new Socket("DESKTOP-IU5NLRI",10086);
            OutputStream outputStream = socket.getOutputStream();
            User user =getUser();
            ObjectOutputStream objectOutputStream = new ObjectOutputStream(outputStream);
            objectOutputStream.writeObject(user);
            socket.shutdownOutput();

            //接受服务器端相响应的结果
            InputStream inputStream = socket.getInputStream();
            byte[] buffer = new byte[1024];
            int length = inputStream.read(buffer);
            System.out.println("服务器相应的消息：" + new String(buffer,0,length));
            socket.shutdownInput();
            //关闭资源
            inputStream.close();
            objectOutputStream.close();
            objectOutputStream.close();
        }
    }

    public static User getUser(){
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入用户名：");
        String username = scanner.next();
        System.out.print("请输入密码：");
        String pwd = scanner.next();
        User user = new User(username,pwd);
        return user;
    }

}

public class loginServer {
    public static void main(String[] args) throws IOException,ClassNotFoundException {

        ServerSocket serverSocket = new ServerSocket(10086);
        System.out.println("*****************服务器已开启... ...*********************");
        while(true){
            Socket server = serverSocket.accept();
            InputStream inputStream = server.getInputStream();
            ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
            User user = (User)objectInputStream.readObject();
            String str = "";
            if("wzry".equals(user.getUsername()) && "123456".equals(user.getPassword())){
                str = "登录成功！";
                System.out.println("欢迎用户  【" + user.getUsername() + "】  登录系统！");
            }else{
                str = "登录失败！";
            }
            server.shutdownInput();

            OutputStream outputStream = server.getOutputStream();
            outputStream.write(str.getBytes());
            server.shutdownOutput();

            //关闭资源
            outputStream.close();
            objectInputStream.close();
            inputStream.close();
            server.close();
        }
    }
}

运行图

?

注：这时程序并没有停止?，需手动停止

优化一下服务端

客户端
public class loginClient2 {


    public static void main(String[] args) throws IOException {
        while(true){
            Socket socket = new Socket("DESKTOP-IU5NLRI",10086);
            OutputStream outputStream = socket.getOutputStream();
            User user =getUser();
            ObjectOutputStream objectOutputStream = new ObjectOutputStream(outputStream);
            objectOutputStream.writeObject(user);
            socket.shutdownOutput();

            //接受服务器端相响应的结果
            InputStream inputStream = socket.getInputStream();
            byte[] buffer = new byte[1024];
            int length = inputStream.read(buffer);
            System.out.println("服务器相应的消息：" + new String(buffer,0,length));
            socket.shutdownInput();
            //关闭资源
            inputStream.close();
            objectOutputStream.close();
            objectOutputStream.close();
        }
    }

    public static User getUser(){
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入用户名：");
        String username = scanner.next();
        System.out.print("请输入密码：");
        String pwd = scanner.next();
        User user = new User(username,pwd);
        return user;
    }

}


服务端

public class loginServer2 {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(10086);
        System.out.println("*****************服务器已开启... ...*********************");

        while(true){
            Socket socket = serverSocket.accept();
            loginThread2 loginThread = new loginThread2(socket);
            new Thread(loginThread).start();
        }
    }
}

public class loginThread2 implements Runnable{
    private Socket socket;

    public loginThread2(Socket socket) {
        this.socket = socket;
    }

    @Override
    public void run() {
        InputStream inputStream = null;
        ObjectInputStream objectInputStream = null;
        OutputStream outputStream = null;
        try {
            inputStream = socket.getInputStream();
            objectInputStream = new ObjectInputStream(inputStream);
            User user = (User)objectInputStream.readObject();
            String str = "";
            if("wzry".equals(user.getUsername()) && "123456".equals(user.getPassword())){
                str = "登录成功！";
                System.out.println("欢迎用户  【" + user.getUsername() + "】  登录系统！");
            }else{
                str = "登录失败！";
            }
            socket.shutdownInput();

            outputStream = socket.getOutputStream();
            outputStream.write(str.getBytes());
            socket.shutdownOutput();

        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                //关闭资源
                outputStream.close();
                objectInputStream.close();
                inputStream.close();
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

现在让他通信后结束运行

public class udpClient {
    public static void main(String[] args) throws IOException {
        //创建DatagramSocket对象
        DatagramSocket datagramSocket = new DatagramSocket();
        //发送数据
        System.out.println("请输入要发送的信息:");
        //定义数据包
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        //getBytes 使用平台的默认字符集将这个(@code String)编码为字节序列，并将结果存储到一个新的字节数组中。
        DatagramPacket datagramPacket = new DatagramPacket(s.getBytes(),s.getBytes().length,InetAddress.getByName("DESKTOP-IU5NLRI"),10086);
        //发送数据包给服务器
        datagramSocket.send(datagramPacket);
        //关闭资源
        datagramSocket.close();
    }
}

public class udpClient {
    public static void main(String[] args) throws IOException {
        //创建DatagramSocket对象
        DatagramSocket datagramSocket = new DatagramSocket();
        //发送数据
        System.out.println("请输入要发送的信息:");
        //定义数据包
        Scanner scanner = new Scanner(System.in);
        String s = scanner.nextLine();
        //getBytes 使用平台的默认字符集将这个(@code String)编码为字节序列，并将结果存储到一个新的字节数组中。
        DatagramPacket datagramPacket = new DatagramPacket(s.getBytes(),s.getBytes().length,InetAddress.getByName("DESKTOP-IU5NLRI"),10086);
        //发送数据包给服务器
        datagramSocket.send(datagramPacket);
        //关闭资源
        datagramSocket.close();
    }
}

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实现图片传输

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

public class picClient {
    public static void main(String[] args) throws IOException {
        FileInputStream fileInputStream = new FileInputStream("1.jpg");
        //创建Socket套接字对象
        Socket client = new Socket("DESKTOP-IU5NLRI",10001);
        //从socket中获取输入流
        OutputStream outputStream = client.getOutputStream();
        //读数据，向服务器写数据
        int read = 0;
        while((read = fileInputStream.read()) != -1){
            outputStream.write(read);
        }
        //截断socket中的输出流
        client.shutdownOutput();

        //读取服务器响应的数据
        InputStream inputStream = client.getInputStream();
        DataInputStream dataInputStream = new DataInputStream(inputStream);
        String a = dataInputStream.readUTF();
        System.out.println("服务器响应的消息：" + a);
        client.shutdownOutput();
        //关资源
        dataInputStream.close();
        inputStream.close();
        fileInputStream.close();
        outputStream.close();client.close();
    }
}

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

public class picServer {

        public static void main(String[] args) throws IOException {
            FileOutputStream fileOutputStream = new FileOutputStream("bajie.jpg");
            //创建ServerSocket对象
            ServerSocket serverSocket = new ServerSocket(10001);
            System.out.println("*****************服务器已开启... ...*********************");
            //开启监听,获取socket对象
            Socket server = serverSocket.accept();
            //从socket中读取客户端上传的图片数据
            InputStream inputStream = server.getInputStream();
            //读取数据，写入服务器端
            int length = 0;
            byte[] buffer = new byte[1024];
            while((length = inputStream.read(buffer))!=-1){
                fileOutputStream.write(buffer,0,length);
            }
            server.shutdownInput();

            //响应客户端一条消息
            OutputStream outputStream = server.getOutputStream();
            DataOutputStream dataOutputStream = new DataOutputStream(outputStream);
            dataOutputStream.writeUTF("上传成功！");
            server.shutdownOutput();
            //关资源
            dataOutputStream.close();
            outputStream.close();
            inputStream.close();
            fileOutputStream.close();
            server.close();
            serverSocket.close();
        }
    }

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