public class FTPClientPool implements ObjectPool<FTPClient> {
  private static Logger logger = LoggerFactory.getLogger(FTPClient.class);

  private static final int DEFAULT_POOL_SIZE = 10;

  public BlockingQueue<FTPClient> blockingQueue;

  private FTPClientFactory factory;

  public FTPClientPool(FTPClientFactory factory) throws Exception {
    this(DEFAULT_POOL_SIZE, factory);
  }

  public FTPClientPool(int poolSize, FTPClientFactory factory) throws Exception {
    this.factory = factory;
    this.blockingQueue = new ArrayBlockingQueue<FTPClient>(poolSize);
    initPool(poolSize);
  }

  /**
   * 初始化連線池
   * @param maxPoolSize
   *                  最大連線數
   * @throws Exception
   */
  private void initPool(int maxPoolSize) throws Exception {
    int count = 0;
    while(count < maxPoolSize) {
      this.addObject();
      count++;
    }
  }

  /**
   * 從連線池中獲取物件
   */
  @Override
  public FTPClient borrowObject() throws Exception {
    FTPClient client = blockingQueue.take();
    if(client == null) {
      client = factory.makeObject();
    } else if(!factory.validateObject(client)) {
      invalidateObject(client);
      client = factory.makeObject();
    }
    return client;
  }

  /**
   * 返還一個物件(連結)
   */
  @Override
  public void returnObject(FTPClient client) throws Exception {
    if ((client != null) && !blockingQueue.offer(client,2,TimeUnit.MINUTES)) {
      try {
        factory.destroyObject(client);
      } catch (Exception e) {
        throw e;
      }
    }
  }

  /**
   * 移除無效的物件(FTP客戶端)
   */
  @Override
  public void invalidateObject(FTPClient client) throws Exception {
    blockingQueue.remove(client);
  }

  /**
   * 增加一個新的連結，超時失效
   */
  @Override
  public void addObject() throws Exception {
    blockingQueue.offer(factory.makeObject(), 2, TimeUnit.MINUTES);
  }

  /**
   * 重新連線
   */
  public FTPClient reconnect() throws Exception {
    return factory.makeObject();
  }

  /**
   * 獲取空閒連結數(這裡暫不實現)
   */
  @Override
  public int getNumIdle() {
    return blockingQueue.size();
  }

  /**
   * 獲取正在被使用的連結數
   */
  @Override
  public int getNumActive() {
    return DEFAULT_POOL_SIZE - getNumIdle();
  }

  @Override
  public void clear() throws Exception {

  }

  /**
   * 關閉連線池
   */
  @Override
  public void close() {
    try {
      while(blockingQueue.iterator().hasNext()) {
        FTPClient client = blockingQueue.take();
        factory.destroyObject(client);
      }
    } catch(Exception e) {
      logger.error("close ftp client pool failed...{}", e);
    }
  }

  @Override
  public void setFactory(PoolableObjectFactory<FTPClient> factory) throws IllegalStateException, UnsupportedOperationException {

  }

  /**
   * 增加一個新的連結，超時失效
   */
  public void addObject(FTPClient ftpClient) throws Exception {
    blockingQueue.put(ftpClient);
  }
}
 

專案下載：