多线程聊天服务器

时间:2014-05-10 16:51:54

标签: java multithreading sockets

我是Threads的新手。我试图从服务器向客户端广播消息。但我不能。似乎服务器总是监听新连接。但我可以使用客户端终端向其他客户端发送消息。我的问题是如何在同时收听时允许输入。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) {
      }
   }
}

1 个答案:

答案 0 :(得分:4)

  1. 您应该在后台线程中监听客户端。您的代码当前没有执行此操作,因此您的服务器实际上已被锁定在无限的while (true)循环中。
  2. 您应该重构代码,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,以便您的主要方法非常简短,这样它只需缠绕手表并开始运行,可以这么说。
  4. 您的格式化代码非常难以阅读。请考虑编辑帖子并修复缩进样式,使其统一且一致。我通常会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)并缩进每个代码块4个空格。
  5. 你几乎不想让你的类扩展Thread。相反,让它实现Runnable(或使用Rod_Algonquin&#39的优秀推荐)。
  6. 不要使用DataInputStream#readLine(...)等弃用的方法,因为这样做可能会很危险。

  7. 例如,您的主要内容可能就像这样......

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

    修改
    注意添加为警告:我通常不使用套接字,服务器套件或创建聊天程序,而且我仍然是使用Executors的新手,但您可以按照以下方式构建代码... < / p>

    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();
          }
    
       }
    }