Java NIO on Android: Attempting to READ/WRITE while connection is still pending?

问题

This question regards Java's NIO on Android (2.2, though I can build for higher APIs if necessary): After performing a SocketChannel connect() to a destination IP address, I register my channel for a READ operation. The problem is that when I try to perform a READ on the resulting selected key set, I receive NotYetConnectedException. While I can check the channel's status with isConnectionPending before I try to READ, I would ideally like to have READ keys be selected only when the connection is actually working. Any ideas?

回答1:

You're doing it wrong.

While the connection is pending, the channel must only be registered for OP_CONNECT.

When OP_CONNECT fires, you must call finishConnect(), and then proceed as follows:

1. If it returns true, you must then deregister OP_CONNECT, and you may then register OP_READ or OP_WRITE.

2. If it returns false, do nothing: the connection is still pending.

3. If it throws an exception, the connect has failed and you must close the channel.

来源：https://stackoverflow.com/questions/13050848/java-nio-on-android-attempting-to-read-write-while-connection-is-still-pending