Netty内建对象

Handler

Handler

SimpleChannelInboundHandler

ChannelInboundHandlerAdapter which allows to explicit only handle a specific type of messages.

只允许显式地处理特定类型的消息

ChannelInboundHandlerAdapter

Pipeline

HttpServerCodec 请求解码和返回编码组合

A combination(组合) of HttpRequestDecoder and HttpResponseEncoder which enables easier server side HTTP implementation.

HttpRequestDecoder和HttpResponseEncoder的组合，使服务器端更容易实现HTTP

LengthFieldBasedFrameDecoder

LengthFieldPrepender

StringDecoder&StringEncoder

DelimiterBasedFrameDecoder 分隔符

A decoder that splits the received ByteBufs by one or more delimiters. It is particularly useful for decoding the frames which ends with a delimiter such as Delimiters or Delimiters newline characters.

解码器将收到的ByteBufs通过一个或者更多的分隔符进行切割。他对于解码结束的帧特别有用诸如分隔符和分隔换行符

IdleStateHandler 空闲检测

Triggers an IdleStateEvent when a Channel has not performed read, write, or both operation for a while.

当Channel一段时间内没有触发读和写操作触发IdleStateEvent

通过继承ChannelInboudHandlerAdapter重写userEventTriggered捕获异常

// 加入handler到pipeline
protected void initChannel(SocketChannel ch) throws Exception {
	ch.pipeline()
    .addLast(new IdleStateHandler(5, 6, 10, TimeUnit.SECONDS))
    .addLast(new CatchHandler()); // 事件处理handler
}
--------------------------------------------------------------
// 捕获异常
public class CatchHandler extends ChannelInboundHandlerAdapter {
   /**
     * Calls {@link ChannelHandlerContext#fireUserEventTriggered(Object)} to forward
     * to the next {@link ChannelInboundHandler} in the {@link ChannelPipeline}.
     *
     * Sub-classes may override this method to change behavior.
     */
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        // super.userEventTriggered(ctx, evt); 默认将异常抛给下一个handler
        if (evt instanceof IdleStateEvent) {
            IdleStateEvent event = (IdleStateEvent) evt;
            switch (event.state()) {
                case READER_IDLE: // 到达时间不出现读
                    break;
                case WRITER_IDLE: // 到达时间不出现写
                    break;
                case ALL_IDLE: // // 到达时间不出现读 写
                    break;
            }
        }
    }
}

LoggingHandler 日志框架

A ChannelHandler that logs all events using a logging framework. By default, all events are logged at DEBUG level.

使用日志框架记录所有事件日志的ChannelHandler。默认所有事件都使用debug等级

ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap
  .group(bossGroup, workerGroup)
  .channel(NioServerSocketChannel.class)
  .handler(new LoggingHandler(LogLevel.INFO))

ChunkedWriteHandler

HttpObjectAggregator

WebSocketServerProtocolHandler

ProtocalType

HttpObject

WebSocketFrame

TextWebSocketFrame

PingWebSocketFrame

PongWebSocketFrame

CloseWebSocketFrame

ContinuationWebSocketFrame

BinaryWebSocketFrame