三.netty學習之ChannelPipeline

時間 2019-11-07

標籤 netty 學習 channelpipeline 欄目 Netty 简体版

原文原文鏈接

官方的文檔裏一直推薦看看這三個類之間的關係. public interface ChannelPipeline extends java.lang.Iterable<java.util.Map.Entry<java.lang.String, io.netty.channel.ChannelHandler>>java

能夠看出,他裏面存的是ChannelHandler的集合他就是一個責任鏈的設計模式實現設計模式

1.pipeline的建立 每個channel都有本身的pipeline, 而且當channel建立的時候自動建立 2.一個event是怎麼在pipeline裏流動的promise

![pipeline中事件的流動](https://static.oschina.net/uploads/img/201510/31014503_tbRZ.png "pipeline中event的流動")

3.傳遞一個事件到下一個handler ChannelHandler要想event傳遞到下一個handler,他必須調用ChannelHandlerContext的方法 1. ** Inbound event propagation methods:**安全

ChannelHandlerContext.fireChannelRegistered()
        ChannelHandlerContext.fireChannelActive()
        ChannelHandlerContext.fireChannelRead(Object)
        ChannelHandlerContext.fireChannelReadComplete()
        ChannelHandlerContext.fireExceptionCaught(Throwable)
        ChannelHandlerContext.fireUserEventTriggered(Object)
        ChannelHandlerContext.fireChannelWritabilityChanged()
        ChannelHandlerContext.fireChannelInactive()
   2.
        **Outbound event propagation methods:**
        ChannelHandlerContext.bind(SocketAddress, ChannelPromise)
        ChannelHandlerContext.connect(SocketAddress, SocketAddress, ChannelPromise)
        ChannelHandlerContext.write(Object, ChannelPromise)
        ChannelHandlerContext.flush()
        ChannelHandlerContext.read()
        ChannelHandlerContext.disconnect(ChannelPromise)
        ChannelHandlerContext.close(ChannelPromise)

下面有一個例子async

public class MyInboundHandler extends ChannelHandlerAdapter {
        @Override
       public void channelActive(ChannelHandlerContext ctx) {
           System.out.println("Connected!");
           ctx.fireChannelActive();
       }
   }
  
   public clas MyOutboundHandler extends ChannelHandlerAdapter {
        @Override
       public void close(ChannelHandlerContext ctx, ChannelPromise promise) {
           System.out.println("Closing ..");
           ctx.close(promise);
       }
   }

構建一個pipeline

如下是代碼ide

static final EventExecutorGroup group = new DefaultEventExecutorGroup(16);
   ...
  
   ChannelPipeline pipeline = ch.pipeline();
  
   pipeline.addLast("decoder", new MyProtocolDecoder());
   pipeline.addLast("encoder", new MyProtocolEncoder());
  
   // Tell the pipeline to run MyBusinessLogicHandler's event handler methods
   // in a different thread than an I/O thread so that the I/O thread is not blocked by
   // a time-consuming task.
   // If your business logic is fully asynchronous or finished very quickly, you don't
   // need to specify a group.
   pipeline.addLast(group, "handler", new MyBusinessLogicHandler());