JAVA Socket的方法说明

 Java代码

/**
 * Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).
 *
 * @param on <code>true</code> to enable TCP_NODELAY,
 * <code>false</code> to disable.
 *
 * @exception SocketException if there is an error
 * in the underlying protocol, such as a TCP error.
 *
 * @since JDK1.1
 *
 * @see #getTcpNoDelay()
 */
public void setTcpNoDelay(boolean on) throws SocketException

    /**
     * Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).
     *
     * @param on <code>true</code> to enable TCP_NODELAY, 
     * <code>false</code> to disable.
     *
     * @exception SocketException if there is an error 
     * in the underlying protocol, such as a TCP error.
     * 
     * @since   JDK1.1
     *
     * @see #getTcpNoDelay()
     */
    public void setTcpNoDelay(boolean on) throws SocketException

• setTcpNoDelay

这是一个设置是否启用Nagle算法,Nagle算法是一个TCP层的通信流量的拥塞控制算法（Flow Control），在大学的计算机网络课本上都会提到这个慢启动(Slow start)”和“拥塞避免(Congestion avoidance)”，“快速重传(Fast retransmit)”、“快速恢复(Fast Recovery)”。

缺省的算法实现一般都是启用的。这样可以处理，防止发送方处理过快，接受方数据处理不过来的情况。但是，如果在实时处理上，通常发送方不需要关心接收方是否能够及时处理数据，因此可能需要设置这个参数。、

如果设置ture，不启用Nagle‘s algorithm

如果为false，启用Nagle's algorithm

缺省值，依赖于socket的具体实现，通常是false。即启用Nagle

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/**
 * Send one byte of urgent data on the socket. The byte to be sent is the lowest eight
 * bits of the data parameter. The urgent byte is
 * sent after any preceding writes to the socket OutputStream
 * and before any future writes to the OutputStream.
 * @param data The byte of data to send
 * @exception IOException if there is an error
 * sending the data.
 * @since 1.4
 */
public void sendUrgentData (int data) throws IOException

   /**
     * Send one byte of urgent data on the socket. The byte to be sent is the lowest eight
     * bits of the data parameter. The urgent byte is
     * sent after any preceding writes to the socket OutputStream
     * and before any future writes to the OutputStream.
     * @param data The byte of data to send
     * @exception IOException if there is an error
     *  sending the data.
     * @since 1.4
     */
    public void sendUrgentData (int data) throws IOException 

 

• sendUrgentData

设置紧急数据包——在socket上发送一个byte的紧急数据，它会在所有socket的输出流（OutputStream)，已经写入之后，但是在其他将要发送的数据之前。

通常，发送紧急数据用于处理一些特殊情况。（如通知对方执行某个控制指令）。

/**
 * Enable/disable SO_TIMEOUT with the specified timeout, in
 * milliseconds. With this option set to a non-zero timeout,
 * a read() call on the InputStream associated with this Socket
 * will block for only this amount of time. If the timeout expires,
 * a <B>java.net.SocketTimeoutException</B> is raised, though the
 * Socket is still valid. The option <B>must</B> be enabled
 * prior to entering the blocking operation to have effect. The
 * timeout must be > 0.
 * A timeout of zero is interpreted as an infinite timeout.
 * @param timeout the specified timeout, in milliseconds.
 * @exception SocketException if there is an error
 * in the underlying protocol, such as a TCP error.
 * @since JDK 1.1
 * @see #getSoTimeout()
 */
public synchronized void setSoTimeout(int timeout) throws SocketException

    /**
     *  Enable/disable SO_TIMEOUT with the specified timeout, in
     *  milliseconds.  With this option set to a non-zero timeout,
     *  a read() call on the InputStream associated with this Socket
     *  will block for only this amount of time.  If the timeout expires,
     *  a <B>java.net.SocketTimeoutException</B> is raised, though the
     *  Socket is still valid. The option <B>must</B> be enabled
     *  prior to entering the blocking operation to have effect. The
     *  timeout must be > 0.
     *  A timeout of zero is interpreted as an infinite timeout.
     * @param timeout the specified timeout, in milliseconds.
     * @exception SocketException if there is an error
     * in the underlying protocol, such as a TCP error. 
     * @since   JDK 1.1
     * @see #getSoTimeout()
     */
    public synchronized void setSoTimeout(int timeout) throws SocketException