Java代码

  1. /**
  2. * Enable/disable TCP_NODELAY (disable/enable Nagle's algorithm).
  3. *
  4. * @param on true to enable TCP_NODELAY,
  5. * false to disable.
  6. *
  7. * @exception SocketException if there is an error
  8. * in the underlying protocol, such as a TCP error.
  9. *
  10. * @since JDK1.1
  11. *
  12. * @see #getTcpNoDelay()
  13. */
  14. 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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Java代码
  1. /**
  2. * Send one byte of urgent data on the socket. The byte to be sent is the lowest eight
  3. * bits of the data parameter. The urgent byte is
  4. * sent after any preceding writes to the socket OutputStream
  5. * and before any future writes to the OutputStream.
  6. * @param data The byte of data to send
  7. * @exception IOException if there is an error
  8. * sending the data.
  9. * @since 1.4
  10. */
  11. 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）。

Java代码
  1. /**
  2. * Enable/disable SO_TIMEOUT with the specified timeout, in
  3. * milliseconds. With this option set to a non-zero timeout,
  4. * a read() call on the InputStream associated with this Socket
  5. * will block for only this amount of time. If the timeout expires,
  6. * a java.net.SocketTimeoutException is raised, though the
  7. * Socket is still valid. The option must be enabled
  8. * prior to entering the blocking operation to have effect. The
  9. * timeout must be > 0.
  10. * A timeout of zero is interpreted as an infinite timeout.
  11. * @param timeout the specified timeout, in milliseconds.
  12. * @exception SocketException if there is an error
  13. * in the underlying protocol, such as a TCP error.
  14. * @since JDK 1.1
  15. * @see #getSoTimeout()
  16. */
  17. public synchronized void setSoTimeout(int timeout) throws SocketException