//中会抛NullPointerException
//因为DefaultChannelPipeline的toString方法如果在DefaultChannelPipeline中没有Handler,
//则DefaultChannelPipeline的head字段为null,从而导致NullPointerException
pipeline = getPipelineFactory().getPipeline();
} catch (Exception e) {
throw new ChannelPipelineException("Failed to initialize a pipeline.", e);
}
// Set the options.
Channel ch = getFactory().newChannel(pipeline);
ch.getConfig().setOptions(getOptions());