java - 具有多个客户端的服务器 - JAVA

Question

鉴于这两个代码，一个用于服务器，另一个用于客户端，我试图让多个客户端与服务器通信，但我不知道如何去做。知道服务器如何识别与他交谈的客户端并回复同一个客户端吗？

服务器:

    import java.io.*;
    import java.net.*;
    public class Provider{
    ServerSocket providerSocket;
    Socket connection = null;
    ObjectOutputStream out;
    ObjectInputStream in;
    String message;
    Provider(){}
    void run()
{
    try{
        //1. creating a server socket
        providerSocket = new ServerSocket(2004, 10);
        //2. Wait for connection
        System.out.println("Waiting for connection");
        connection = providerSocket.accept();
        System.out.println("Connection received from " + connection.getInetAddress().getHostName());
        //3. get Input and Output streams
        out = new ObjectOutputStream(connection.getOutputStream());
        out.flush();
        in = new ObjectInputStream(connection.getInputStream());
        sendMessage("Connection successful");

        //4. The two parts communicate via the input and output streams
        do{
            try{
                message = (String)in.readObject();

                System.out.println("client>" + message);
                if (message.equals("byee"))
                    sendMessage("Wosil");
            }
            catch(ClassNotFoundException classnot){
                System.err.println("Data received in unknown format");
            }
        }while(!message.equals("bye"));
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
    finally{
        //4: Closing connection
        try{
            in.close();
            out.close();
            providerSocket.close();
        }
        catch(IOException ioException){
            ioException.printStackTrace();
        }
    }
}
void sendMessage(String msg)
{
    try{
        out.writeObject(msg);
        out.flush();
        System.out.println("Zame-Server>" + msg);
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
}
public static void main(String args[])
{
    Provider server = new Provider();
    while(true){
        server.run();
        }
    }
}

客户端

import java.io.*;
import java.net.*;
public class Requester{
Socket requestSocket;
ObjectOutputStream out;
ObjectInputStream in;
String message;
Requester(){}
void run()
{
    try{
        //1. creating a socket to connect to the server
        requestSocket = new Socket("localhost", 2004);
        System.out.println("Connected to localhost in port 2004");
        //2. get Input and Output streams
        out = new ObjectOutputStream(requestSocket.getOutputStream());
        out.flush();
        in = new ObjectInputStream(requestSocket.getInputStream());
        //3: Communicating with the server

                sendMessage("Hi my server");
                sendMessage("SENDING");
                message = "byee";
                sendMessage(message);
        do{
            try{
                message = (String)in.readObject();
                System.out.println("server>" + message);


            }
            catch(ClassNotFoundException classNot){
                System.err.println("data received in unknown format");
            }
        }while(!message.equals("bye"));
    }
    catch(UnknownHostException unknownHost){
        System.err.println("You are trying to connect to an unknown host!");
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
    finally{
        //4: Closing connection
        try{
            in.close();
            out.close();
            requestSocket.close();
        }
        catch(IOException ioException){
            ioException.printStackTrace();
        }
    }
}
void sendMessage(String msg)
{
    try{
        out.writeObject(msg);
        out.flush();
        System.out.println("Zame-Client>" + msg);
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
}
public static void main(String args[])
{
    Requester client = new Requester();
    client.run();
}
}

Answer 1

您的问题似乎有两个方面。第一个处理并发(如何启动多个客户端并使它们与服务器通信)。为此，您必须具备 Java 线程的基本知识。

你的问题的第二部分:服务器如何跟踪多个客户端(这也表明你的客户端和服务器之间的通信是有状态的):你可能想设计一个简单的协议(protocol)，客户端和服务器通过该协议(protocol)进行通信.例如，当客户端与服务器通信时，它必须使用唯一标识符标记其消息。服务器使用该标识符来跟踪和保留它必须用来完成任务的任何资源，客户端要求它(如果这是您的要求所要求的)。