Java Socket Programming Example-TCP Server Thread Pool

1. Server return service class:

import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.net.Socket; 
import java.util.logging.Level; 
import java.util.logging.Logger; 
  
public class EchoProtocol implements Runnable { 
  private static final int BUFSIZE = 32; // Size (in bytes) of I/O buffer 
  private Socket clientSocket; // Socket connect to client 
  private Logger logger; // Server logger 
  
  public EchoProtocol(Socket clientSocket, Logger logger) { 
    this.clientSocket = clientSocket; 
    this.logger = logger; 
  } 
  
  public static void handleEchoClient(Socket clientSocket, Logger logger) { 
    try { 
      // Get the input and output I/O streams from socket 
      InputStream in = clientSocket.getInputStream(); 
      OutputStream out = clientSocket.getOutputStream(); 
  
      int recvMsgSize; // Size of received message 
      int totalBytesEchoed = 0; // Bytes received from client 
      byte[] echoBuffer = new byte[BUFSIZE]; // Receive Buffer 
      // Receive until client closes connection, indicated by -1 
      while ((recvMsgSize = in.read(echoBuffer)) != -1) { 
        out.write(echoBuffer, 0, recvMsgSize); 
        totalBytesEchoed += recvMsgSize; 
      } 
  
      logger.info("Client " + clientSocket.getRemoteSocketAddress() + ", echoed " + totalBytesEchoed + " bytes."); 
        
    } catch (IOException ex) { 
      logger.log(Level.WARNING, "Exception in echo protocol", ex); 
    } finally { 
      try { 
        clientSocket.close(); 
      } catch (IOException e) { 
      } 
    } 
  } 
  
  public void run() { 
    handleEchoClient(this.clientSocket, this.logger); 
  } 
}

2. Tcp server that starts a new thread for each client request:

import java.io.IOException; 
import java.net.ServerSocket; 
import java.net.Socket; 
import java.util.logging.Logger; 
  
public class TCPEchoServerThread { 
  
  public static void main(String[] args) throws IOException { 
    // Create a server socket to accept client connection requests 
    ServerSocket servSock = new ServerSocket(5500); 
  
    Logger logger = Logger.getLogger("practical"); 
  
    // Run forever, accepting and spawning a thread for each connection 
    while (true) { 
      Socket clntSock = servSock.accept(); // Block waiting for connection 
      // Spawn thread to handle new connection 
      Thread thread = new Thread(new EchoProtocol(clntSock, logger)); 
      thread.start(); 
      logger.info("Created and started Thread " + thread.getName()); 
    } 
    /* NOT REACHED */
  } 
}

3. Tcp with fixed number of threads Server:

import java.io.IOException; 
import java.net.ServerSocket; 
import java.net.Socket; 
import java.util.logging.Level; 
import java.util.logging.Logger; 
  
public class TCPEchoServerPool { 
  public static void main(String[] args) throws IOException { 
    int threadPoolSize = 3; // Fixed ThreadPoolSize 
  
    final ServerSocket servSock = new ServerSocket(5500); 
    final Logger logger = Logger.getLogger("practical"); 
  
    // Spawn a fixed number of threads to service clients 
    for (int i = 0; i < threadPoolSize; i++) { 
      Thread thread = new Thread() { 
        public void run() { 
          while (true) { 
            try { 
              Socket clntSock = servSock.accept(); // Wait for a connection 
              EchoProtocol.handleEchoClient(clntSock, logger); // Handle it 
            } catch (IOException ex) { 
              logger.log(Level.WARNING, "Client accept failed", ex); 
            } 
          } 
        } 
      }; 
      thread.start(); 
      logger.info("Created and started Thread = " + thread.getName()); 
    } 
  } 
}

4. Use thread pool (threads using Spring will have the concepts of queue, maximum number of threads, minimum number of threads and timeout time)

1. Thread pool tool class :

import java.util.concurrent.*; 
  
/** 
 * 任务执行者 
 * 
 * @author Watson Xu 
 * @since 1.0.0 <p>2013-6-8 上午10:33:09</p> 
 */
public class ThreadPoolTaskExecutor { 
  
  private ThreadPoolTaskExecutor() { 
  
  } 
  
  private static ExecutorService executor = Executors.newCachedThreadPool(new ThreadFactory() { 
    int count; 
  
    /* 执行器会在需要自行任务而线程池中没有线程的时候来调用该程序。对于callable类型的调用通过封装以后转化为runnable */ 
    public Thread newThread(Runnable r) { 
      count++; 
      Thread invokeThread = new Thread(r); 
      invokeThread.setName("Courser Thread-" + count); 
      invokeThread.setDaemon(false);// //???????????? 
  
      return invokeThread; 
    } 
  }); 
  
  public static void invoke(Runnable task, TimeUnit unit, long timeout) throws TimeoutException, RuntimeException { 
    invoke(task, null, unit, timeout); 
  } 
  
  public static <T> T invoke(Runnable task, T result, TimeUnit unit, long timeout) throws TimeoutException, 
      RuntimeException { 
    Future<T> future = executor.submit(task, result); 
    T t = null; 
    try { 
      t = future.get(timeout, unit); 
    } catch (TimeoutException e) { 
      throw new TimeoutException("Thread invoke timeout ..."); 
    } catch (Exception e) { 
      throw new RuntimeException(e); 
    } 
    return t; 
  } 
  
  public static <T> T invoke(Callable<T> task, TimeUnit unit, long timeout) throws TimeoutException, RuntimeException { 
    // 这里将任务提交给执行器，任务已经启动，这里是异步的。 
    Future<T> future = executor.submit(task); 
    // System.out.println("Task aready in thread"); 
    T t = null; 
    try { 
      /* 
       * 这里的操作是确认任务是否已经完成，有了这个操作以后 
       * 1)对invoke()的调用线程变成了等待任务完成状态 
       * 2)主线程可以接收子线程的处理结果 
       */
      t = future.get(timeout, unit); 
    } catch (TimeoutException e) { 
      throw new TimeoutException("Thread invoke timeout ..."); 
    } catch (Exception e) { 
      throw new RuntimeException(e); 
    } 
  
    return t; 
  } 
}

2. Scalable Tcp server:

import java.io.IOException; 
import java.net.ServerSocket; 
import java.net.Socket; 
import java.util.concurrent.TimeUnit; 
import java.util.logging.Logger; 
  
import demo.callable.ThreadPoolTaskExecutor; 
  
  
public class TCPEchoServerExecutor { 
  
  public static void main(String[] args) throws IOException { 
    // Create a server socket to accept client connection requests 
    ServerSocket servSock = new ServerSocket(5500); 
  
    Logger logger = Logger.getLogger("practical"); 
      
    // Run forever, accepting and spawning threads to service each connection 
    while (true) { 
      Socket clntSock = servSock.accept(); // Block waiting for connection 
      //executorService.submit(new EchoProtocol(clntSock, logger)); 
      try { 
        ThreadPoolTaskExecutor.invoke(new EchoProtocol(clntSock, logger), TimeUnit.SECONDS, 3); 
      } catch (Exception e) { 
      }  
      //service.execute(new TimelimitEchoProtocol(clntSock, logger)); 
    } 
    /* NOT REACHED */
  } 
}

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