netty4是2.5.6引入的,2.5.6之前的netty用的是netty3。在dubbo源码中相较于netty3,添加netty4主要仅仅改了两个类:NettyServer,NettyClient。还有就是编解码。

使用方式:

服务端:

 <dubbo:provider server="netty4"/>

客户端:

 <dubbo:consumer client="netty4" />

一、服务端 - NettyServer

 package com.alibaba.dubbo.remoting.transport.netty4;

 import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.ExecutorUtil;
import com.alibaba.dubbo.common.utils.NetUtils;
import com.alibaba.dubbo.remoting.Channel;
import com.alibaba.dubbo.remoting.ChannelHandler;
import com.alibaba.dubbo.remoting.RemotingException;
import com.alibaba.dubbo.remoting.Server;
import com.alibaba.dubbo.remoting.transport.AbstractServer;
import com.alibaba.dubbo.remoting.transport.dispatcher.ChannelHandlers;
import com.alibaba.dubbo.remoting.transport.netty4.logging.NettyHelper; import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.PooledByteBufAllocator;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.util.concurrent.DefaultThreadFactory; import java.net.InetSocketAddress;
import java.util.Collection;
import java.util.HashSet;
import java.util.Map; public class NettyServer extends AbstractServer implements Server { private static final Logger logger = LoggerFactory.getLogger(NettyServer.class); private Map<String, Channel> channels; // <ip:port, channel> private ServerBootstrap bootstrap; private io.netty.channel.Channel channel; private EventLoopGroup bossGroup;
private EventLoopGroup workerGroup; public NettyServer(URL url, ChannelHandler handler) throws RemotingException {
super(url, ChannelHandlers.wrap(handler, ExecutorUtil.setThreadName(url, SERVER_THREAD_POOL_NAME)));
} @Override
protected void doOpen() throws Throwable {
NettyHelper.setNettyLoggerFactory(); bootstrap = new ServerBootstrap(); bossGroup = new NioEventLoopGroup(1, new DefaultThreadFactory("NettyServerBoss", true));
workerGroup = new NioEventLoopGroup(getUrl().getPositiveParameter(Constants.IO_THREADS_KEY, Constants.DEFAULT_IO_THREADS),
new DefaultThreadFactory("NettyServerWorker", true)); final NettyServerHandler nettyServerHandler = new NettyServerHandler(getUrl(), this);
channels = nettyServerHandler.getChannels(); bootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childOption(ChannelOption.TCP_NODELAY, Boolean.TRUE)
.childOption(ChannelOption.SO_REUSEADDR, Boolean.TRUE)
.childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT)
.childHandler(new ChannelInitializer<NioSocketChannel>() {
@Override
protected void initChannel(NioSocketChannel ch) throws Exception {
NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), NettyServer.this);
ch.pipeline()//.addLast("logging",new LoggingHandler(LogLevel.INFO))//for debug
.addLast("decoder", adapter.getDecoder())
.addLast("encoder", adapter.getEncoder())
.addLast("handler", nettyServerHandler);
}
});
// bind
ChannelFuture channelFuture = bootstrap.bind(getBindAddress());
channelFuture.syncUninterruptibly();
channel = channelFuture.channel(); } @Override
protected void doClose() throws Throwable {
try {
if (channel != null) {
// unbind.
channel.close();
}
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
try {
Collection<com.alibaba.dubbo.remoting.Channel> channels = getChannels();
if (channels != null && channels.size() > 0) {
for (com.alibaba.dubbo.remoting.Channel channel : channels) {
try {
channel.close();
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
}
}
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
try {
if (bootstrap != null) {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
try {
if (channels != null) {
channels.clear();
}
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
} public Collection<Channel> getChannels() {
Collection<Channel> chs = new HashSet<Channel>();
for (Channel channel : this.channels.values()) {
if (channel.isConnected()) {
chs.add(channel);
} else {
channels.remove(NetUtils.toAddressString(channel.getRemoteAddress()));
}
}
return chs;
} public Channel getChannel(InetSocketAddress remoteAddress) {
return channels.get(NetUtils.toAddressString(remoteAddress));
} public boolean isBound() {
return channel.isActive();
}
}

netty4的写法与netty3有很大不同,下面是netty3:(http://www.cnblogs.com/java-zhao/p/7625596.html

 /**
* 启动netty服务,监听客户端连接
*/
@Override
protected void doOpen() throws Throwable {
NettyHelper.setNettyLoggerFactory();
ExecutorService boss = Executors.newCachedThreadPool(new NamedThreadFactory("NettyServerBoss", true));
ExecutorService worker = Executors.newCachedThreadPool(new NamedThreadFactory("NettyServerWorker", true));
ChannelFactory channelFactory = new NioServerSocketChannelFactory(boss, worker, getUrl().getPositiveParameter(Constants.IO_THREADS_KEY, Constants.DEFAULT_IO_THREADS));
bootstrap = new ServerBootstrap(channelFactory); final NettyHandler nettyHandler = new NettyHandler(getUrl(), this);
channels = nettyHandler.getChannels();
// https://issues.jboss.org/browse/NETTY-365
// https://issues.jboss.org/browse/NETTY-379
// final Timer timer = new HashedWheelTimer(new NamedThreadFactory("NettyIdleTimer", true));
bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
public ChannelPipeline getPipeline() {
NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), NettyServer.this);
ChannelPipeline pipeline = Channels.pipeline();
/*int idleTimeout = getIdleTimeout();
if (idleTimeout > 10000) {
pipeline.addLast("timer", new IdleStateHandler(timer, idleTimeout / 1000, 0, 0));
}*/
pipeline.addLast("decoder", adapter.getDecoder());
pipeline.addLast("encoder", adapter.getEncoder());
pipeline.addLast("handler", nettyHandler);
return pipeline;
}
});
// bind
channel = bootstrap.bind(getBindAddress());
}

二、客户端 - NettyClient

 package com.alibaba.dubbo.remoting.transport.netty4;

 import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.Version;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.NetUtils;
import com.alibaba.dubbo.remoting.ChannelHandler;
import com.alibaba.dubbo.remoting.RemotingException;
import com.alibaba.dubbo.remoting.transport.AbstractClient;
import com.alibaba.dubbo.remoting.transport.netty4.logging.NettyHelper; import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.PooledByteBufAllocator;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.util.concurrent.DefaultThreadFactory; import java.util.concurrent.TimeUnit; public class NettyClient extends AbstractClient { private static final Logger logger = LoggerFactory.getLogger(NettyClient.class); private static final NioEventLoopGroup nioEventLoopGroup = new NioEventLoopGroup(Constants.DEFAULT_IO_THREADS, new DefaultThreadFactory("NettyClientWorker", true)); private Bootstrap bootstrap; private volatile Channel channel; // volatile, please copy reference to use public NettyClient(final URL url, final ChannelHandler handler) throws RemotingException {
super(url, wrapChannelHandler(url, handler));
} @Override
protected void doOpen() throws Throwable {
NettyHelper.setNettyLoggerFactory();
final NettyClientHandler nettyClientHandler = new NettyClientHandler(getUrl(), this);
bootstrap = new Bootstrap();
bootstrap.group(nioEventLoopGroup)
.option(ChannelOption.SO_KEEPALIVE, true)
.option(ChannelOption.TCP_NODELAY, true)
.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT)
//.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, getTimeout())
.channel(NioSocketChannel.class); if (getTimeout() < 3000) {
bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 3000);
} else {
bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, getTimeout());
} bootstrap.handler(new ChannelInitializer() {
protected void initChannel(Channel ch) throws Exception {
NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), NettyClient.this);
ch.pipeline()//.addLast("logging",new LoggingHandler(LogLevel.INFO))//for debug
.addLast("decoder", adapter.getDecoder())
.addLast("encoder", adapter.getEncoder())
.addLast("handler", nettyClientHandler);
}
});
} protected void doConnect() throws Throwable {
long start = System.currentTimeMillis();
ChannelFuture future = bootstrap.connect(getConnectAddress());
try {
boolean ret = future.awaitUninterruptibly(3000, TimeUnit.MILLISECONDS); if (ret && future.isSuccess()) {
Channel newChannel = future.channel();
try {
// Close old channel
Channel oldChannel = NettyClient.this.channel; // copy reference
if (oldChannel != null) {
try {
if (logger.isInfoEnabled()) {
logger.info("Close old netty channel " + oldChannel + " on create new netty channel " + newChannel);
}
oldChannel.close();
} finally {
NettyChannel.removeChannelIfDisconnected(oldChannel);
}
}
} finally {
if (NettyClient.this.isClosed()) {
try {
if (logger.isInfoEnabled()) {
logger.info("Close new netty channel " + newChannel + ", because the client closed.");
}
newChannel.close();
} finally {
NettyClient.this.channel = null;
NettyChannel.removeChannelIfDisconnected(newChannel);
}
} else {
NettyClient.this.channel = newChannel;
}
}
} else if (future.cause() != null) {
throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server "
+ getRemoteAddress() + ", error message is:" + future.cause().getMessage(), future.cause());
} else {
throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server "
+ getRemoteAddress() + " client-side timeout "
+ getConnectTimeout() + "ms (elapsed: " + (System.currentTimeMillis() - start) + "ms) from netty client "
+ NetUtils.getLocalHost() + " using dubbo version " + Version.getVersion());
}
} finally {
if (!isConnected()) {
//future.cancel(true);
}
}
} @Override
protected void doDisConnect() throws Throwable {
try {
NettyChannel.removeChannelIfDisconnected(channel);
} catch (Throwable t) {
logger.warn(t.getMessage());
}
} @Override
protected void doClose() throws Throwable {
//can't shutdown nioEventLoopGroup
//nioEventLoopGroup.shutdownGracefully();
} @Override
protected com.alibaba.dubbo.remoting.Channel getChannel() {
Channel c = channel;
if (c == null || !c.isActive())
return null;
return NettyChannel.getOrAddChannel(c, getUrl(), this);
}
}

netty3:http://www.cnblogs.com/java-zhao/p/7811040.html

 protected void doOpen() throws Throwable {
NettyHelper.setNettyLoggerFactory();
bootstrap = new ClientBootstrap(channelFactory);
// config
// @see org.jboss.netty.channel.socket.SocketChannelConfig
bootstrap.setOption("keepAlive", true);
bootstrap.setOption("tcpNoDelay", true);
bootstrap.setOption("connectTimeoutMillis", getTimeout());
final NettyHandler nettyHandler = new NettyHandler(getUrl(), this);
bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
public ChannelPipeline getPipeline() {
NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), NettyClient.this);
ChannelPipeline pipeline = Channels.pipeline();
pipeline.addLast("decoder", adapter.getDecoder());
pipeline.addLast("encoder", adapter.getEncoder());
pipeline.addLast("handler", nettyHandler);
return pipeline;
}
});
} protected void doConnect() throws Throwable {
long start = System.currentTimeMillis();
ChannelFuture future = bootstrap.connect(getConnectAddress());
try {
boolean ret = future.awaitUninterruptibly(getConnectTimeout(), TimeUnit.MILLISECONDS); if (ret && future.isSuccess()) {
Channel newChannel = future.getChannel();
newChannel.setInterestOps(Channel.OP_READ_WRITE);
try {
// 关闭旧的连接
Channel oldChannel = NettyClient.this.channel; // copy reference
if (oldChannel != null) {
try {
if (logger.isInfoEnabled()) {
logger.info("Close old netty channel " + oldChannel + " on create new netty channel " + newChannel);
}
oldChannel.close();
} finally {
NettyChannel.removeChannelIfDisconnected(oldChannel);
}
}
} finally {
if (NettyClient.this.isClosed()) {
try {
if (logger.isInfoEnabled()) {
logger.info("Close new netty channel " + newChannel + ", because the client closed.");
}
newChannel.close();
} finally {
NettyClient.this.channel = null;
NettyChannel.removeChannelIfDisconnected(newChannel);
}
} else {
NettyClient.this.channel = newChannel;
}
}
} else if (future.getCause() != null) {
throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server "
+ getRemoteAddress() + ", error message is:" + future.getCause().getMessage(), future.getCause());
} else {
throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server "
+ getRemoteAddress() + " client-side timeout "
+ getConnectTimeout() + "ms (elapsed: " + (System.currentTimeMillis() - start) + "ms) from netty client "
+ NetUtils.getLocalHost() + " using dubbo version " + Version.getVersion());
}
} finally {
if (!isConnected()) {
future.cancel();
}
}
}

还有就是编解码。

后续会做netty4源码阅读计划。

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