Как реализовать пул соединений TCP в java?

Question

Здесь мне удалось установить соединение между одним сервером и единственным клиентом, но теперь мое новое препятствие - это то, как достичь pool соединений TCP на стороне клиента в JAVA. Я прошел через многие сайты, но в конце не найдено ни одного плодотворного решения. Здесь class, который я использовал для получения connection к server

public class TCPIPCommunicator { 

private final String MODULE="TCPIPCommunicator :"; 

//private DeviceEntity deviceEntity; 
private static InetAddress inetServer = null; 
private static int devicePort = -1; 
private Socket clientSocket; 
private BufferedOutputStream outputStream; 
private BufferedInputStream inputStream; 
private static boolean isLinkActive = false; 
private String IP=""; 

public TCPIPCommunicator(String IP, int devicePort) { 
    this.IP=IP; 
    this.devicePort=devicePort; 
    initialize(); 
} 

public static boolean isLinkActive(){ 
    return isLinkActive; 
} 

public static void setLinkStatus(boolean status){ 
    isLinkActive = status; 
} 

private void initialize() { 
    System.out.println(MODULE+ "Inside initialize()"); 
    setLinkStatus(false); 
    try{ 
     inetServer = InetAddress.getByName(IP); 
    }catch (UnknownHostException uhe) { 
     System.out.println(MODULE+ "Error while creating inetaddress, Reason:"+uhe.getMessage()); 
    } 
    System.out.println(MODULE+ "Connecting to - " +inetServer.getHostAddress() + ":" + devicePort); 
    establishConnection(); 

     if(!isLinkActive()){ 
      //sendNotification(TCPIPConstants.LINK_DOWN); 
      releaseResources(); 
      //resumeLinkSanityHelper(); 
     } 
    System.out.println(MODULE+ "out of initialize(), isLinkActive :" + isLinkActive()); 
} 

public boolean establishConnection(){ 
    boolean isConnected = false; 
    //Get the Connection to PMS Server. 
    if(inetServer != null && devicePort > 0){ 
     try{ 
      clientSocket = new Socket(inetServer, devicePort); 
      clientSocket.setKeepAlive(true); 
     }catch(ConnectException ce){ 
      ce.printStackTrace(); 
      setLinkStatus(false); 
      System.out.println(MODULE+ "Exception in initialize() " + "Couldnot Connect Server. Reason:"+ce.getMessage()); 
     }catch(Exception e){ 
      e.printStackTrace(); 
      setLinkStatus(false);   
      System.out.println(MODULE+ "Exception in initialize() " + "while creating socket ,Reason: " + e.getMessage()); 
     } 

     //If got connection, Get the streams. 
     if(clientSocket != null && !clientSocket.isClosed()){ 
      System.out.println(MODULE+ "in initialize(), Got Socket Connection."); 
      try{ 
       outputStream = new BufferedOutputStream(clientSocket.getOutputStream()); 
      }catch(Exception e){ 
       e.printStackTrace(); 
       outputStream=null; 
       setLinkStatus(false); 
       System.out.println(MODULE+ "Exception in initialize() while getting socket outputStream : " + e.getMessage()); 
      } 

      if(outputStream != null){ 
       try{ 
        inputStream = new BufferedInputStream(clientSocket.getInputStream()); 
       }catch(Exception e){ 
        setLinkStatus(false); 
        System.out.println(MODULE+ "Exception in initialize() " + "while getting socket inputStream : " + e.getMessage()); 
       } 
       setLinkStatus(true); 
      } 
      if(outputStream != null && inputStream != null){ 
       isConnected = true; 
      } 
     }else{ 
      System.out.println(MODULE+ "in initialize(), Connection is closed or null."); 
      setLinkStatus(false); 
     } 
    } 
    return isConnected; 
} 



public int writeData(byte[] msg){ 
    int retValue = -1; 
    try{ 
     if(isLinkActive() && (outputStream !=null)){ 
      System.out.println(MODULE+ "Writting data ::::" + new String(msg)+ "::::"); 
      outputStream.write(msg);// ed 
      outputStream.flush(); 
      retValue = 1; 
     }else{ 
      System.out.println(MODULE+ " in writeData() link is down so status:" + retValue); 
     } 
    }catch(Exception e){ 
     e.printStackTrace(); 
     retValue = -1; 
     System.out.println(MODULE+ "Exception in write() < message to be sent was = " + new String(msg) + " > : " + e.getMessage()); 
    } 
    if(retValue == -1 && isLinkActive()){ 
     setLinkStatus(false); 
     //sendNotification(TCPIPConstants.LINK_DOWN); 
     //releaseResources(); 
     //resumeLinkSanityHelper(); 
    } 
    System.out.println(MODULE+ " in writeData() Write status for ::"+ new String(msg) + ":: -->" +retValue); 
    return retValue; 
} 

public String readData() { 
    System.out.println(MODULE+"\tInside readDAta"); 
    String response = null; 
    int bytesReceived=-1; 
    byte[] readBuffer = new byte[1024]; 
    try{ 
     long timetoread = System.currentTimeMillis(); 
     if(inputStream == null || !(isLinkActive())){ 
      System.out.println(MODULE+"Inputstream is null or link is down, returning null"); 
      return null; 
     } 

     try{ 
      System.out.println("Waiting to read data"); 
      bytesReceived = inputStream.read(readBuffer); 
      System.out.println(MODULE+"# Byte Receieved #" + bytesReceived); 
     }catch(Exception e){ 
      e.printStackTrace(); 
      System.out.println(MODULE+"Error in readData() , Reason:"+e.getMessage()); 
      if(isLinkActive()){ 
       setLinkStatus(false); 
       //sendNotification(TCPIPConstants.LINK_DOWN); 
       releaseResources(); 
       //resumeLinkSanityHelper(); 
      } 
     } 
     if(bytesReceived > 0){   
      response = new String(readBuffer,0,bytesReceived); // ed 
      timetoread = System.currentTimeMillis() - timetoread; 
      System.out.println(MODULE + "Total Bytes Received: " + bytesReceived); 
      System.out.println(MODULE+ "Total Time Taken : " + timetoread); 
      System.out.println(MODULE+ "Length of data received : " + response.length()); 
      System.out.println(MODULE+ "Data Received : ####" + response + "####"); 
     }else{ 
      ////////// HERE MEANS TCP CONNECTION STATUS WILL CLOSE_WAIT 
      ////////// SO RELEASING CONNECTION. 
      System.out.println(MODULE+ " Releasing Resource. bytesReceived is <= 0 : Total Bytes Received :"+ bytesReceived); 
      if(isLinkActive()){ 
       setLinkStatus(false); 
       //sendNotification(TCPIPConstants.LINK_DOWN); 
       releaseResources(); 
       //resumeLinkSanityHelper(); 
      } 
      System.out.println(MODULE+ " Resource has been released."); 
     } 
    }catch(Exception e){ 
     e.printStackTrace(); 
     System.out.println(MODULE+ "In catch : Data Received : ####" + response + "####"); 
     System.out.println(MODULE+ "Exception in readdata() : " + e); 
    }finally{ 
     readBuffer=null; 
    } 
    return response; 
} 



public void releaseResources(){ 
    System.out.println(MODULE+ "Releasing Resources...."); 
    try{ 
     if(clientSocket !=null) 
      clientSocket.close(); 
    }catch(Exception e){ 
     System.out.println(MODULE+ "In releaseResources() :Error closing socket."+e.getMessage()); 
    } 
    try{ 
     if(inputStream !=null) 
      inputStream.close(); 

    }catch(Exception e){ 
     System.out.println(MODULE+ "In releaseResources() :Error closing inputStream."+e.getMessage());   
    } 

    try{ 
     if(outputStream != null){ 
      outputStream.close(); 
     } 
    }catch(Exception e){ 
     System.out.println(MODULE+ "in releaseResources() :Error closing outputStream."); 
    } 
    System.out.println(MODULE + "Resources Relased...");   
} 



} 

Здесь establishConnection() метод будет установить connection на сервер. Любая помощь могла бы помочь.

Примечание: Я думал об использовании ThreadPoolExecutor, но поскольку требование является синхронным, я отказался от этой идеи его использования.

Answer 1

Вы можете создать переменную Set<Socket> sockets хранить все clientSocket вы created.Every подключения к разъему сервера, вы можете поместить сокет клиента в этом set.So этого набор работает как бассейн.

Answer 2

Пример кода, как показано ниже, я использую карту, ключ - «host-port», а значение - LinkedList, содержащий сокеты, связанные с одним и тем же URL-адресом.

public class SocketPool{ 
    Map<String,LinkedList<Socket>> sockets; 

public boolean establishConnection(String inetServer , int devicePort){ 
    boolean result = false; 
    try { 
     Socket clientSocket = new Socket(inetServer, devicePort); 
     String socketKey = inetServer + "-" + devicePort; 
     if(clientSocket.isConnected()&&sockets.containsKey(socketKey)){ 
      sockets.get(socketKey).add(clientSocket); 
     }else if(clientSocket.isConnected()&&!sockets.containsKey(socketKey)){ 
      LinkedList<Socket> socketSet = new LinkedList<Socket>(); 
      socketSet.add(clientSocket); 
      sockets.put(socketKey, socketSet); 
     } 
     result = true; 
    } catch (UnknownHostException e) { 
     result = false; 
    } catch (IOException e) { 
     result = false; 
    } 
    return result; 
} 

public Socket fetchSocket(String inetServer , int devicePort){ 
    String socketKey = inetServer + "-" + devicePort; 
    Socket clientSocket =null; 
    if(sockets.containsKey(socketKey)&&!sockets.get(socketKey).isEmpty()){ 
     clientSocket = sockets.get(socketKey).removeLast(); 
     int size = sockets.get(socketKey).size(); 
     if(size==0){ 
      sockets.remove(socketKey); 
     } 
    } 
     return clientSocket; 
} 
//other functions 
}