????11??public final static int SO_TIMEOUT = 0x1006;
/**
*  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 {
if (isClosed())
throw new SocketException("Socket is closed");
if (timeout < 0)
throw new IllegalArgumentException("timeout can't be negative");
getImpl().setOption(SocketOptions.SO_TIMEOUT?? new Integer(timeout));
}
?????????????????????????socket?????????????timeout?????0????????????????????????????????????????
????12??public final static int SO_SNDBUF = 0x1001;
?????????????￡??????????????????8096??????8K??????????Java???????????????????С?????????????????????????????setSendBufferSize??????????????????????С??
????13??public final static int SO_RCVBUF = 0x1002;
?????????????￡???????????????????8096??????8K??????????Java??????????????????С?????????????????????????????setReceiveBufferSize??????????????????????С??
????14??public final static int SO_KEEPALIVE = 0x0008;
?????????????????????True???????????????????????2С??????????????????????????????????????????????????
????1?????????????????ACK??????????????????OK???????????????????????????????2С???????????????
????2???????????????RST?????????????????????????????????????
????3???????????δ?????????????????11??????????Socket????????????????????12?????????????????????????????Socket??????
????15??public final static int SO_OOBINLINE = 0x1003;
??????????Socket?????????????Socket???sendUrgentData??????????????????????????????????????????????????????????????????????????????????????????OutputStream????????????????????????????????????????????????????????????????????????????????в???????????????????????????OutputStream??????sendUrgentData?????????