多线程聊天服务器

Question

我是线程新手。我正在尝试将消息从服​​务器广播到客户端。但我不能。似乎服务器总是在监听一个新的连接。但我可以使用客户端终端向其他客户端发送消息。我的问题是如何在收听的同时允许输入。这是代码。

MultiThreadChatServerSync.java

import java.io.InputStreamReader;
import java.io.DataInputStream;
import java.io.PrintStream;
import java.io.IOException;
import java.net.Socket;
import java.net.ServerSocket;
import java.io.BufferedReader;

public class MultiThreadChatServerSync extends Thread {

   private static ServerSocket serverSocket = null;
   private static Socket clientSocket = null;
   private static Socket serversSocket = null;
   private static DataInputStream iss = null;
   private static PrintStream oss = null;

   private static final int maxClientsCount = 10;
   private static final clientThread[] threads = new clientThread[maxClientsCount];

   public static void main(String args[]) {
      int num = 0;
      int portNumber = 2222;
      if (args.length < 1) {
         System.out.println("Usage: java MultiThreadChatServerSync<portNumber> "Nowusingnumber=" + portNumber);
      } else {
         portNumber = Integer.valueOf(args[0]).intValue();
      }
      try {
         serverSocket = new ServerSocket(portNumber);
      } catch (IOException e) {
         System.out.println(e);
      }
      DataInputStream iss = null;
      while (true) {
         try {
            System.out.println("5");

            num++;

            // I want to be able to input text here to the server which will be
            // send to different clients
            // But I cannot

            clientSocket = serverSocket.accept();
            int i = 0;
            for (i = 0; i < maxClientsCount; i++) {
               if (threads[i] == null) {
                  System.out.println("6");
                  (threads[i] = new clientThread(clientSocket, threads))
                        .start();
                  break;
               }
            }
            if (i == maxClientsCount) {
               PrintStream os = new PrintStream(clientSocket.getOutputStream());
               os.println("Server too busy. Try later.");
               os.close();
               clientSocket.close();
            }
         } catch (IOException e) {
            System.out.println(e);
         }
      }

   }
}

class clientThread extends Thread {

   private String clientName = null;
   private DataInputStream is = null;
   private PrintStream os = null;
   private Socket clientSocket = null;
   private final clientThread[] threads;
   private int maxClientsCount;

   public clientThread(Socket clientSocket, clientThread[] threads) {
      this.clientSocket = clientSocket;
      this.threads = threads;
      maxClientsCount = threads.length;
   }

   public void run() {
      int maxClientsCount = this.maxClientsCount;
      clientThread[] threads = this.threads;

      try {

         is = new DataInputStream(clientSocket.getInputStream());
         os = new PrintStream(clientSocket.getOutputStream());
         String name;
         while (true) {
            os.println("Enter your name.");
            name = is.readLine().trim();
            if (name.indexOf('@') == -1) {
               break;
            } else {
               os.println("The name should not contain '@' character.");
            }
         }

         os.println("Welcome " + name
               + " to our chat room.\nTo leave enter /quit in a new line.");
         synchronized (this) {
            for (int i = 0; i < maxClientsCount; i++) {
               if (threads[i] != null && threads[i] == this) {
                  clientName = "@" + name;
                  break;
               }
            }
            for (int i = 0; i < maxClientsCount; i++) {
               if (threads[i] != null && threads[i] != this) {
                  threads[i].os.println("*** A new user " + name
                        + " entered the chat room !!! ***");
               }
            }
         }

         while (true) {
            String line = is.readLine();
            if (line.startsWith("/quit")) {
               break;
            }

            if (line.startsWith("@")) {
               String[] words = line.split("\\s", 2);
               if (words.length > 1 && words[1] != null) {
                  words[1] = words[1].trim();
                  if (!words[1].isEmpty()) {
                     synchronized (this) {
                        for (int i = 0; i < maxClientsCount; i++) {
                           if (threads[i] != null && threads[i] != this
                                 && threads[i].clientName != null
                                 && threads[i].clientName.equals(words[0])) {
                              threads[i].os.println("<" + name + "> "
                                    + words[1]);

                              this.os.println(">" + name + "> " + words[1]);
                              break;
                           }
                        }
                     }
                  }
               }
            } else {

               synchronized (this) {
                  for (int i = 0; i < maxClientsCount; i++) {
                     if (threads[i] != null && threads[i].clientName != null) {
                        threads[i].os.println("<" + name + "> " + line);
                     }
                  }
               }
            }
         }
         synchronized (this) {
            for (int i = 0; i < maxClientsCount; i++) {
               if (threads[i] != null && threads[i] != this
                     && threads[i].clientName != null) {
                  threads[i].os.println("*** The user " + name
                        + " is leaving the chat room !!! ***");
               }
            }
         }
         os.println("*** Bye " + name + " ***");

         synchronized (this) {
            for (int i = 0; i < maxClientsCount; i++) {
               if (threads[i] == this) {
                  threads[i] = null;
               }
            }
         }

         is.close();
         os.close();
         clientSocket.close();
      } catch (IOException e) {
      }
   }
}

Answer 1

1. 您应该在后台线程中监听客户端。您的代码目前没有这样做，因此您的服务器实际上被锁定在一个无休止的while (true) 循环中。
2. 您应该重构您的代码，这样您的方法就不会那么庞大和笨拙。
3. 您应该重构您的代码，使您的 main 方法非常简短，这样它就可以简单地为手表上链并开始运行，可以这么说。
4. 您的格式化代码很难阅读。请考虑编辑您的帖子并修复您的缩进样式，使其统一且一致。我通常避免使用制表符进行缩进（论坛软件通常不能很好地使用制表符）并将每个代码块缩进 4 个空格。
5. 您几乎不想让您的类扩展 Thread。相反，让它实现 Runnable（或使用 Rod_Algonquin 的优秀推荐）。
6. 请勿使用已弃用的方法，例如 DataInputStream#readLine(...)，因为这样做可能很危险。

---

例如，你的 main 可以这么简单...

public static void main(String[] args) {
   MyServer myServer = new MyServer();
   myServer.getThingsRunning();
}

---

编辑
作为警告添加的注释：我通常不使用套接字、服务器套接字或创建聊天程序，而且我在使用 Executors 方面还是新手，但您可以按照这些思路构建代码......

public class MultiServer implements Runnable {
   public static final int PORT_NUMBER = 2222;
   private static final int THREAD_POOL_COUNT = 20;
   private List<MultiClient> clientList = new ArrayList<>();
   private ServerSocket serverSocket;
   private ExecutorService clientExecutor = Executors.newFixedThreadPool(THREAD_POOL_COUNT);

   public MultiServer() throws IOException {
      serverSocket = new ServerSocket(PORT_NUMBER);
   }

   @Override
   public void run() {
      // embed your socket acceptance loop in a Runnable's run method
      while (true) {
         try {
            Socket clientSocket = serverSocket.accept();
            MultiClient client = new MultiClient(clientSocket);
            clientList.add(client);
            clientExecutor.execute(client);
         } catch (IOException e) {
            // TODO notify someone of problem!
            e.printStackTrace();
         }
      }
   }

   // ..... more methods and such

   public static void main(String[] args) {
      try {
         MultiServer multiServer = new MultiServer();
         new Thread(multiServer).start();
      } catch (IOException e) {
         e.printStackTrace();
      }

   }
}