register 不允许 block 模式，而默认的是

Exception in thread "main" java.nio.channels.IllegalBlockingModeException
at java.nio.channels.spi.AbstractSelectableChannel.register(Unknown Source)
at com.nio.echo.IOHandler.<init>(NIOEchoServer.java:99)
at com.nio.echo.AcceptHandler.doHandle(NIOEchoServer.java:77)
at com.nio.echo.NIOEchoServer.startServer(NIOEchoServer.java:52)
at com.nio.echo.NIOEchoServer.main(NIOEchoServer.java:59)

serverSocketChannel.configureBlocking(false);
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

　　

register 不允许 block 模式，而默认的是。 把它设置成false就可以了。

你应该仔细看看 register 的API说明。里面很清楚

* @throws IllegalBlockingModeException
* If this channel is in blocking mode