ChannelHandler

類圖

ChannelHandler

public interface ChannelHandler {void handlerAdded(ChannelHandlerContext ctx) throws Exception;void handlerRemoved(ChannelHandlerContext ctx) throws Exception; }

ChannelInboundHandler

inbound事件：從I/O線程流向用戶業務handler的事件。

public interface ChannelInboundHandler extends ChannelHandler {void channelRegistered(ChannelHandlerContext ctx) throws Exception;void channelUnregistered(ChannelHandlerContext ctx) throws Exception;void channelActive(ChannelHandlerContext ctx) throws Exception;void channelInactive(ChannelHandlerContext ctx) throws Exception;void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception;void channelReadComplete(ChannelHandlerContext ctx) throws Exception;void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception;void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception;/*** Gets called if a {@link Throwable} was thrown.*/@Override@SuppressWarnings("deprecation")void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception; }

ChannelOutboundHandler

outbound事件：由用戶或代碼發起的I/O操作事件。

public interface ChannelOutboundHandler extends ChannelHandler {void bind(ChannelHandlerContext ctx, SocketAddress localAddress, ChannelPromise promise) throws Exception;void connect(ChannelHandlerContext ctx, SocketAddress remoteAddress,SocketAddress localAddress, ChannelPromise promise) throws Exception;void disconnect(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception;void close(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception;void deregister(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception;void read(ChannelHandlerContext ctx) throws Exception;void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception;void flush(ChannelHandlerContext ctx) throws Exception; }

ByteToMessageDecoder

用于把讀取到的字節數組或字節緩沖區解析為業務POJO。

MessageToMessageDecoder

MessageToMessageDecoder為二次解碼器，用于把一個對象二次解析為另一個對象。

LineBasedFrameDecoder

通過長度處理半包，粘包問題

ChannelPipeline

Netty將Channel的數據管道抽象為ChannelPipeline，消息在ChannelPipeline中流動和傳遞。ChannelPipeline持有I/O事件攔截器ChannelHandler的鏈表，由ChannelHandler對I/O事件進行處理。

在ChannelPipeline 中ChannelHandler由ChannelHandlerContext進行了封裝，包含next，prev指針。

volatile AbstractChannelHandlerContext next;volatile AbstractChannelHandlerContext prev;

調用事件時，調用next或者prev的同名事件。

static void invokeChannelRegistered(final AbstractChannelHandlerContext next) {EventExecutor executor = next.executor();if (executor.inEventLoop()) {next.invokeChannelRegistered();} else {executor.execute(new Runnable() {@Overridepublic void run() {next.invokeChannelRegistered();}});}}

ChannelPipeline 包含2個屬性：head，tail，當fireXXX()時，調用head或tail的相關方法。

final AbstractChannelHandlerContext head;final AbstractChannelHandlerContext tail; public final ChannelPipeline fireChannelUnregistered() {AbstractChannelHandlerContext.invokeChannelUnregistered(head);return this;}

?

總結

以上是生活随笔為你收集整理的Netty--ChannelHandler和ChannelPipeline的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。