如何讓多個客戶端連接到服務器Java

Question

我編寫了一個基本的isnatnt消息程序，但它只允許其他客戶端連接到服務器。 我將在代碼中進行哪些更改，以便它可以接受多個客戶端，而不是讓他們排隊等候。

Client.java

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.Color;
import java.awt.Font; 

public class Client extends JFrame{

   private JTextField userText;
   private JTextArea chatWindow;
   private ObjectOutputStream output;
   private ObjectInputStream input;
   private String message = "";
   private String serverIP;
   private Socket connection;
   private JTextField UsernameField;
   private String Username;
   Color RED = new Color(255,0,0);
   Color ORANGE = new Color(255,128,0);
   Color YELLOW = new Color(255,255,0);
   Color LIGHT_GREEN = new Color(51,255,51);
   Color GREEN = new Color(0,255,0);
   Color DARK_GREEN = new Color(0,102,0);
   Color LIGHT_BLUE = new Color(51,51,255);
   Color BLUE = new Color(0,0,255);
   Color DARK_BLUE = new Color(0,0,102);
   Color PURPLE = new Color(153,0,153);



   //constructor
   public Client(String host){
      super("Azrin IM");
      serverIP = host;

      userText = new JTextField("Enter Message Here.");
      userText.addMouseListener(new MouseAdapter() {
          public void mouseClicked(MouseEvent e) {
              if (userText.getText().equals("Enter Message Here.")) // User has not entered text yet
                  userText.setText("");
          }
      });



      userText.setEditable(true);
      UsernameField = new JTextField("Enter Username Here.");
      UsernameField.addMouseListener(new MouseAdapter() {
          public void mouseClicked(MouseEvent e) {
              if (UsernameField.getText().equals("Enter Username Here.")) // User has not entered text yet
                  UsernameField.setText("");
          }
      });

      add(new JLabel ("Enter Username Here."));
      UsernameField.setEditable(true);
      userText.addActionListener(
         new ActionListener(){
            public void actionPerformed(ActionEvent event){
                Username = UsernameField.getText();
                sendMessage(event.getActionCommand());
                userText.setText("");
                UsernameField.setText("");
            }
         }
      );
      add(userText, BorderLayout.SOUTH);
      add (UsernameField, BorderLayout.NORTH);
      chatWindow = new JTextArea();
      add(new JScrollPane(chatWindow), BorderLayout.CENTER);
      setSize(400,300);
      setVisible(true);
   }


   //connect to server
   public void startRunning(){
      try{
         connectToServer();
         setupStreams();
         whileChatting();
      }catch(EOFException eofException){
         showMessage("\n Client terminated connection");
      }catch(IOException ioException){
         ioException.printStackTrace();
      }finally{
         Disconnect();
      }
   }

   //connect to server
   private void connectToServer() throws IOException{
      showMessage("Attempting connection... \n");
      connection = new Socket(InetAddress.getByName(serverIP), 6969);
      showMessage("Connected to: " + connection.getInetAddress().getHostName() );
   }

   //set up streams to send and receive messages
   private void setupStreams() throws IOException{
      output = new ObjectOutputStream(connection.getOutputStream());
      output.flush();
      input = new ObjectInputStream(connection.getInputStream());
      showMessage("\n Now connected to Server! \n");
   }

   //while chatting with server
   private void whileChatting() throws IOException{
      ableToType(true);
      do{
         try{
            message = (String) input.readObject();
            showMessage("\n" + message);
         }catch(ClassNotFoundException classNotfoundException){
            showMessage("\n I dont know that object type");
         }
      }while(!message.equals(Username + ": END"));



   }



   //close the streams and sockets
   private void Disconnect(){
      showMessage("\n Disconnected.");
      ableToType(false);
      try{
         output.close();
         input.close();
         connection.close();
      }catch(IOException ioException){
         ioException.printStackTrace();
      }
   }

   //send messages to server
   private void sendMessage(String message){
      try{
         output.writeObject(Username + ": " + message);
         output.flush();
         showMessage("\n" + Username + ": " + message);
         if (message.equals("RED")){
          chatWindow.setForeground(RED);
         }
         if (message.equals("ORANGE")){
              chatWindow.setForeground(ORANGE);
            }
         if (message.equals("YELLOW")){
               chatWindow.setForeground(YELLOW);
           }
         // I am aware I need to space these if staments better :) .
if (message.equals("LIGHT_GREEN")){
     chatWindow.setForeground(LIGHT_GREEN);
 }
if (message.equals("GREEN")){
     chatWindow.setForeground(GREEN);
}
if (message.equals("DARK_GREEN")){
     chatWindow.setForeground(DARK_GREEN);
}
if (message.equals("LIGHT_BLUE")){
     chatWindow.setForeground(LIGHT_BLUE);
}
if (message.equals("BLUE")){
     chatWindow.setForeground(BLUE);
}
if (message.equals("DARK_BLUE")){
     chatWindow.setForeground(DARK_BLUE);
}
if (message.equals("PURPLE")){
     chatWindow.setForeground(PURPLE);
}



      }catch(IOException ioException){
         chatWindow.append("\n something messed up sending message hoss!");
      }
   }

   //change/update chatWindow
   private void showMessage(final String m){
      SwingUtilities.invokeLater(
         new Runnable(){
            public void run(){
               chatWindow.append(m);
            }
         }
      );
   }

   //gives user permission to type crap into the text box
   private void ableToType(final boolean tof){
      SwingUtilities.invokeLater(
         new Runnable(){
            public void run(){
               userText.setEditable(tof);
            }
         }
      );      
   }
}

ClientTest.java

import javax.swing.JFrame;

public class ClientTest {
   public static void main(String[] args) {
      Client charlie;
      charlie = new Client("69.125.13.88");
      charlie.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      charlie.startRunning();
   }
}

Server.java

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Server extends JFrame{

   private JTextField userText;
   private JTextArea chatWindow;
   private ObjectOutputStream output;
   private ObjectInputStream input;
   private ServerSocket server;
   private Socket connection;

   //constructor
   public Server(){
      super("Azrin IM Server");
      userText = new JTextField();
      userText.setEditable(false);
      userText.addActionListener(
         new ActionListener(){
            public void actionPerformed(ActionEvent event){
               sendMessage(event.getActionCommand());
               userText.setText("");
            }
         }
      );
      add(userText, BorderLayout.NORTH);
      chatWindow = new JTextArea();
      add(new JScrollPane(chatWindow));
      setSize(500,200);
      setVisible(true);
   }

   //set up and run the server
   public void startRunning(){
      try{
         server = new ServerSocket(6969, 100);
         while(true){
            try{
               waitForConnection();
               setupStreams();
               whileChatting();
            }catch(EOFException eofException){
               showMessage("\n Server ended the connection! ");
            }finally{
               closeCrap();
            }
         }
      }catch(IOException ioException){
         ioException.printStackTrace();
      }
   }

 //wait for connection, then display connection information
   private void waitForConnection() throws IOException{
      showMessage(" Waiting for someone to connect... \n");
      connection = server.accept();
      showMessage(" Now connected to " + connection.getInetAddress().getHostName());
   }

   //get stream to send and receive data
   private void setupStreams() throws IOException{
      output = new ObjectOutputStream(connection.getOutputStream());
      output.flush();
      input = new ObjectInputStream(connection.getInputStream());
      showMessage("\n Streams are now setup! \n");
   }

   //during the chat conversation
   private void whileChatting() throws IOException{
      String message = " You are now connected! ";
      sendMessage(message);
      ableToType(true);
      do{
         try{
            message = (String) input.readObject();
            showMessage("\n" + message);
         }catch(ClassNotFoundException classNotFoundException){
            showMessage("\n idk wtf that user sent!");
         }
      }while(!message.equals("CLIENT - END"));
   }

   //close streams and sockets after you are done chatting
   private void closeCrap(){
      showMessage("\n Closing connections... \n");
      ableToType(false);
      try{
         output.close();
         input.close();
         connection.close();
      }catch(IOException ioException){
         ioException.printStackTrace();
      }
   }

   //send a message to client
   private void sendMessage(String message){
      try{
         output.writeObject("Josh A - " + message);
         output.flush();
         showMessage("\nSERVER - " + message);
      }catch(IOException ioException){
         chatWindow.append("\n ERROR: DUDE I CANT SEND THAT MESSAGE");
      }
   }

   //updates chatWindow
   private void showMessage(final String text){
      SwingUtilities.invokeLater(
         new Runnable(){
            public void run(){
               chatWindow.append(text);
            }
         }
      );
   }

   //let the user type stuff into their box
   private void ableToType(final boolean tof){
      SwingUtilities.invokeLater(
         new Runnable(){
            public void run(){
               userText.setEditable(tof);
            }
         }
      );
   }

}

ServerTest.java

import javax.swing.JFrame;

public class ServerTest {
   public static void main(String[] args) {
      Server sally = new Server();
      sally.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      sally.startRunning();
   }

}

Answer 1

普通螺紋示例

這是“普通”線程示例，可能是您可能會發現的更常見的示例。 這樣做的問題是，您可能會失去對線程的控制，並使數百個傾斜的線程都在運行，從而消耗系統資源...

它很簡單，確實展示了您需要實現的基本概念...

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

public class TestSocketThread {

    // Need away to stop the program...
    private static boolean acceptMore = true;

    public static void main(String[] args) {
        new TestSocketThread();
    }

    public TestSocketThread() {
        ServerSocket serverSocket = null;
        try {
             serverSocket = new ServerSocket(6969, 100);
            while (acceptMore) {
                Socket socket = serverSocket.accept();
                new Thread(new SocketThread(socket)).start();    
            }
        } catch (IOException exp) {
            exp.printStackTrace();
        } finally {
            try {
                serverSocket.close();
            } catch (Exception e) {
            }
        }
    }

    public class SocketThread implements Runnable {

        private Socket socket;

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

        @Override
        public void run() {
            // Process socket...
        }
    }
}

執行器服務示例

執行程序服務更加靈活，並提供了對普通線程更好的管理控制，包括（按照本示例）固定線程池。

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class ExecutorSocketTest {

    // Need away to stop the program...
    private static boolean acceptMore = true;

    public static void main(String[] args) {
        new ExecutorSocketTest();
    }

    public ExecutorSocketTest() {
        ServerSocket serverSocket = null;
        ExecutorService executorService = Executors.newFixedThreadPool(100);
        try {
             serverSocket = new ServerSocket(6969, 100);
            while (acceptMore) {
                Socket socket = serverSocket.accept();
                executorService.submit(new SocketCallable(socket));
            }
        } catch (IOException exp) {
            exp.printStackTrace();
        } finally {
            try {
                serverSocket.close();
            } catch (Exception e) {
            }
            executorService.shutdownNow();
        }
    }

    /**
     *
     * @author swhitehead
     */
    public class SocketCallable implements Callable {

        private Socket socket;

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

        @Override
        public Object call() throws Exception {
            // Process socket requests...
            return null;
        }
    }
}

您的工作是現在離開並閱讀有關Java並發的所有信息。