java - 为 FtpClient 设置连接超时

Question

当对没有 Activity ftp 服务的现有主机使用 ftpClient.connect 时，超时仅在 5 分钟后发生，这太长了。

我尝试设置不同的超时(setDefaultTimeout、setDataTimeout)，但没有任何改变。

FtpClient 继承自 SocketClient，它有一个 setConnectTimeout 方法，但是当我使用它时，我得到一个 java.lang.NoSuchMethodError: org/apache/commons/net/ftp/FTPClient.setConnectTimeout 运行时。这似乎是因为某些 J2SW 1.2 兼容性，如 Commons-net FAQ 中所述:

问:如何设置连接超时？ http://wiki.apache.org/commons/Net/FrequentlyAskedQuestions

他们建议实现自己的 SocketFactory，使用特定超时从扩展的 Socket 类创建对象。但是，当尝试使用 ftpClient.setSocketFactory 时，我还会收到 java.lang.NoSuchMethodError。

对我如何减少连接超时有什么帮助吗？

Answer 1

    FTPClient ftp = new FTPClient();

    ftp.setDefaultTimeout();
    ftp.setDataTimeout();
    ftp.setConnectTimeout();
    ftp.setSoTimeout();
    ftp.setControlKeepAliveTimeout();
    ftp.setControlKeepAliveReplyTimeout();

来自 Apache 文档:

   /**
     * Set the default timeout in milliseconds to use when opening a socket.
     * This value is only used previous to a call to
     * {@link #connect connect()}
     * and should not be confused with {@link #setSoTimeout setSoTimeout()}
     * which operates on an the currently opened socket.  _timeout_ contains
     * the new timeout value.
     * <p>
     * @param timeout  The timeout in milliseconds to use for the socket
     *                 connection.
     */
    void setDefaultTimeout(int timeout);


    /**
     * Sets the timeout in milliseconds to use when reading from the
     * data connection.  This timeout will be set immediately after
     * opening the data connection, provided that the value is &ge; 0.
     * <p>
     * <b>Note:</b> the timeout will also be applied when calling accept()
     * whilst establishing an active local data connection.
     * @param  timeout The default timeout in milliseconds that is used when
     *        opening a data connection socket. The value 0 means an infinite timeout.
     */
    void setDataTimeout(int timeout)
    /**
     * Sets the connection timeout in milliseconds, which will be passed to the {@link java.net.Socket} object's
     * connect() method.
     * @param connectTimeout The connection timeout to use (in ms)
     * @since 2.0
     */
    void setConnectTimeout(int connectTimeout);
    /**
     * Set the timeout in milliseconds of a currently open connection.
     * Only call this method after a connection has been opened
     * by {@link #connect connect()}.
     * <p>
     * To set the initial timeout, use {@link #setDefaultTimeout(int)} instead.
     *
     * @param timeout  The timeout in milliseconds to use for the currently
     *                 open socket connection.
     * @exception SocketException If the operation fails.
     * @throws NullPointerException if the socket is not currently open
     */
    void setSoTimeout(int timeout) throws SocketException;
    /**
     * Set the time to wait between sending control connection keepalive messages
     * when processing file upload or download.
     *
     * @param controlIdle the wait (in secs) between keepalive messages. Zero (or less) disables.
     * @since 3.0
     * @see #setControlKeepAliveReplyTimeout(int)
     */
    void setControlKeepAliveTimeout(long controlIdle);

    /**
     * Set how long to wait for control keep-alive message replies.
     *
     * @param timeout number of milliseconds to wait (defaults to 1000)
     * @since 3.0
     * @see #setControlKeepAliveTimeout(long)
     */
    void setControlKeepAliveReplyTimeout(int timeout)