服务器向客户端发送消息

Question

我对 Java 比较陌生，在创建多客户端/服务器聊天时遇到问题。

我需要实现服务器，以便它可以从一个或多个客户端接收多条消息，并将所有这些消息发送给所有客户端。因此，假设有两个客户端，client1 将消息“hi”发送到服务器。服务器会将该消息发送到客户端 1 和客户端 2（它会发回到所有可能连接到服务器的客户端）。

另外，我如何将客户的用户名与他们的消息相关联？如果 client1 发送“hi”，我希望 Client1 和 Client2 中的 TextAreas 显示消息说“client1：hi”。

这些实现是在 JavaFX 中完成的。

服务器代码：

package server;

import java.io.*;
import java.net.*;
import java.util.*;
import javafx.application.Platform;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TextArea;

public class ServerFormController implements Initializable{
    @FXML
    public TextArea svrLog;
    private int clientNo = 0;

    ArrayList<HandleAClient> clients = new ArrayList<>();

   //@Override
  // public void run()
  // {

  // }

  @Override
  public void initialize(URL url, ResourceBundle rb) {
    new Thread( () ->
    {
        try{

            ServerSocket serverSocket = new ServerSocket(8000);
            svrLog.appendText("Server started at " + new Date() + '\n');

            while (true)
            {
                Socket socket = serverSocket.accept();
                svrLog.appendText("Worked \n");

                clientNo++;

                //svrLog.appendText("Starting thread for client " + clientNo + "at"
               // + new Date() + '\n');

               // InetAddress inetAddress = socket.getInetAddress();
                //svrLog.appendText("Client " + clientNo + "'s host name is "
                //+ inetAddress.getHostName() + "\n");
              // svrLog.appendText("Client " + clientNo + "'s IP Address is "
               // + inetAddress.getHostAddress() + "\n");

                new Thread(new HandleAClient(socket)).start();
            }

        } catch (IOException ex) {
            svrLog.appendText("Couldn't create ServerSocket! \n");
        }
    }).start();
   }

   /** Creates individual client socket*/
   class HandleAClient implements Runnable {
      private Socket socket;
      DataInputStream inputFromClient = null;
      DataOutputStream outputToClient = null;
      //ServerFormController svr;

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

      public void run()
      {
          try{
              inputFromClient = new DataInputStream(socket.getInputStream());
              outputToClient = new DataOutputStream(socket.getOutputStream());

              while (true)
              {
                  String msg = inputFromClient.readUTF();
                 // for(int i = 0; i < clients.size(); i++) // probably because object in client contain null datastreams
                 //   clients.get(i).outputToClient.writeUTF(msg); // nope.
                  outputToClient.writeUTF(msg);
                  svrLog.appendText(msg);
                  svrLog.appendText("New message received from client. Sent to all clients.");

              }
          } catch (IOException ex) {
              svrLog.appendText("Could not create data stream with client! \n");
          }
      }
  }
 }

客户端代码：

package handlerclient;

import java.io.*;
import java.net.*;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;

public class HandlerClientFormController implements Initializable {
    @FXML
    private TextField ipAdrText; // TextField to get the IP Address
    @FXML
    private TextField usernameText; // TextField to get the user's chat name
    @FXML
    private Button clientConnectBtn;  // Tries to connect to server
    @FXML
    private TextArea msgLogTxtArea; // Displays all the messages between the clients
    @FXML
    private TextArea msgSendTxtArea; // TextArea to get the message from the client
    @FXML
    private Button clientSendBtn;  // Sends the message from the client to the server

    DataOutputStream toServer = null;
    DataInputStream fromServer = null;

    /**
     * Initializes the controller class.
     */
    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    

    @FXML
    private void onConnectBtnClick(ActionEvent event) {
    try{
        Socket socket = new Socket(ipAdrText.getText(), 8000);
        fromServer = new DataInputStream(socket.getInputStream());
        toServer = new DataOutputStream(socket.getOutputStream());
    }
    catch (IOException ex)
    {
        msgLogTxtArea.appendText("Could not connect to server!");
    }
}

    @FXML
    private void onSendBtnClick(ActionEvent event) {
       try{
            toServer.writeUTF(msgSendTxtArea.getText());
            toServer.flush();

            String newmsg = fromServer.readUTF();

            msgLogTxtArea.appendText(newmsg + '\n');
        }
        catch (IOException ex)
        {
            msgLogTxtArea.appendText("Could not send/receive message! \n");
        }
    }

}

Answer 1

例如，它可以通过扩展 HandleAClient 的构造函数来完成。
想法 - 保存在客户端处理程序客户端的信息。
在创建 HandleAClient 的实例时，在您的 ServerFormController 中，我们有关于客户端编号的信息。 我们可以将它作为构造函数的附加参数提供给 HandleAClient，因此当客户端处理程序接收到来自客户端的消息时，它将能够使用具体客户端的名称制作“个性化”消息。