在本人写的前一篇文章中，谈及有关如何利用Netty开发实现，高性能RPC服务器的一些设计思路、设计原理，以及具体的实现方案（具体参见：谈谈如何使用Netty开发实现高性能的RPC服务器）。在文章的最后提及到，其实基于该方案设计的RPC服务器的处理性能，还有优化的余地。于是利用周末的时间，在原来NettyRPC框架的基础上，加以优化重构，本次主要优化改造点如下：
1、NettyRPC中对RPC消息进行编码、解码采用的是Netty自带的ObjectEncoder、ObjectDecoder（对象编码、解码器），该编码、解码器基于的是Java的原生序列化机制，从已有的文章以及测试数据来看，Java的原生序列化性能效率不高，而且产生的序列化二进制码流太大，故本次在优化中，引入RPC消息序列化协议的概念。所谓消息序列化协议，就是针对RPC消息的序列化、反序列化过程进行特殊的定制，引入第三方编解码框架。本次引入的第三方编解码框架有Kryo、Hessian。这里，不得不再次提及一下，对象序列化、反序列化的概念，在RPC的远程服务调用过程中，需要把消息对象通过网络传输，这个就要用到序列化将对象转变成字节流，到达另外一端之后，再反序列化回来变成消息对象。
2、引入Google Guava并发编程框架对NettyRPC的NIO线程池、业务线程池进行重新梳理封装。
3、利用第三方编解码框架（Kryo、Hessian）的时候，考虑到高并发的场景下，频繁的创建、销毁序列化对象，会非常消耗JVM的内存资源，影响整个RPC服务器的处理性能，因此引入对象池化（Object Pooling）技术。众所周知，创建新对象并初始化，可能会消耗很多的时间。当需要产生大量对象的时候，可能会对性能造成一定的影响。为了解决这个问题，除了提升硬件条件之外，对象池化技术就是这方面的银弹，而Apache Commons Pool框架就是对象池化技术的一个很好的实现（开源项目路径：http://commons.apache.org/proper/commons-pool/download_pool.cgi）。本文中的Hessian池化工作，主要是基于Apache Commons Pool框架，进行封装处理。
本文将着重，从上面的三个方面，对重构优化之后的NettyRPC服务器的实现思路、实现方式进行重点讲解。首先请大家简单看下，本次优化之后的NettyRPC服务器支持的序列化协议，如下图所示：
可以很清楚的看到，优化之后的NettyRPC可以支持Kryo、Hessian、Java本地序列化三种消息序列化方式。其中Java本地序列化方式，相信大家应该很熟悉了，再次不在重复讲述。现在我们重点讲述一下，另外两种序列化方式：
1、Kryo序列化。它是针对Java，而定制实现的高效对象序列化框架，相比Java本地原生序列化方式，Kryo在处理性能上、码流大小上等等方面有很大的优化改进。目前已知的很多著名开源项目，都引入采用了该序列化方式。比如alibaba开源的dubbo RPC等等。本文中采用的Kryo的默认版本是基于：kryo-3.0.3。它的下载链接是：https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-3.0.3。为什么采用这个版本？主要原因我上面也说明了，出于应对高并发场景下，频繁地创建、销毁序列化对象，会非常消耗JVM的内存资源、以及时间。Kryo的这个发行版本中，集成引入了序列化对象池功能模块（KryoFactory、KryoPool），这样我们就不必再利用Apache Commons Pool对其进行二次封装。
2、Hessian序列化。Hessian本身是一种序列化协议，它比Java原生的序列化、反序列化速度更快、序列化出来的数据也更小。它是采用二进制格式进行数据传输，而且，目前支持多种语言格式。本文中采用的是：hessian-4.0.37 版本，它的下载链接是：http://hessian.caucho.com/#Java。
接下来，先来看下优化之后的NettyRPC的消息协议编解码包（newlandframework.netty.rpc.serialize.support、newlandframework.netty.rpc.serialize.support.kryo、newlandframework.netty.rpc.serialize.support.hessian）的结构，如下图所示：
其中RPC请求消息结构代码如下：
/** * @filename:MessageRequest.java * * Newland Co. Ltd. All rights reserved. * * @Description:rpc服务请求结构 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.model; import java.io.Serializable; import org.apache.commons.lang.builder.ReflectionToStringBuilder; public class MessageRequest implements Serializable { private String messageId; private String className; private String methodName; private Class<?>[] typeParameters; private Object[] parametersVal; public String getMessageId() { return messageId; } public void setMessageId(String messageId) { this.messageId = messageId; } public String getClassName() { return className; } public void setClassName(String className) { this.className = className; } public String getMethodName() { return methodName; } public void setMethodName(String methodName) { this.methodName = methodName; } public Class<?>[] getTypeParameters() { return typeParameters; } public void setTypeParameters(Class<?>[] typeParameters) { this.typeParameters = typeParameters; } public Object[] getParameters() { return parametersVal; } public void setParameters(Object[] parametersVal) { this.parametersVal = parametersVal; } public String toString() { return ReflectionToStringBuilder.toStringExclude(this, new String[]{"typeParameters", "parametersVal"}); } }
RPC应答消息结构，如下所示：
/** * @filename:MessageResponse.java * * Newland Co. Ltd. All rights reserved. * * @Description:rpc服务应答结构 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.model; import java.io.Serializable; import org.apache.commons.lang.builder.ReflectionToStringBuilder; public class MessageResponse implements Serializable { private String messageId; private String error; private Object resultDesc; public String getMessageId() { return messageId; } public void setMessageId(String messageId) { this.messageId = messageId; } public String getError() { return error; } public void setError(String error) { this.error = error; } public Object getResult() { return resultDesc; } public void setResult(Object resultDesc) { this.resultDesc = resultDesc; } public String toString() { return ReflectionToStringBuilder.toString(this); } }
现在，我们就来对上述的RPC请求消息、应答消息进行编解码框架的设计。由于NettyRPC中的协议类型，目前已经支持Kryo序列化、Hessian序列化、Java原生本地序列化方式。考虑到可扩展性，故要抽象出RPC消息序列化，协议类型对象（RpcSerializeProtocol），它的代码实现如下所示：
/** * @filename:RpcSerializeProtocol.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC消息序序列化协议类型 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support; import org.apache.commons.lang.builder.ReflectionToStringBuilder; import org.apache.commons.lang.builder.ToStringStyle; public enum RpcSerializeProtocol { //目前由于没有引入跨语言RPC通信机制，暂时采用支持同构语言Java序列化/反序列化机制的第三方插件 //NettyRPC目前已知的序列化插件有:Java原生序列化、Kryo、Hessian JDKSERIALIZE("jdknative"), KRYOSERIALIZE("kryo"), HESSIANSERIALIZE("hessian"); private String serializeProtocol; private RpcSerializeProtocol(String serializeProtocol) { this.serializeProtocol = serializeProtocol; } public String toString() { ReflectionToStringBuilder.setDefaultStyle(ToStringStyle.SHORT_PREFIX_STYLE); return ReflectionToStringBuilder.toString(this); } public String getProtocol() { return serializeProtocol; } }
针对不同编解码序列化的框架（这里主要是指Kryo、Hessian），再抽象、萃取出一个RPC消息序列化/反序列化接口（RpcSerialize）、RPC消息编解码接口（MessageCodecUtil）。
/** * @filename:RpcSerialize.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC消息序列化/反序列化接口定义 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public interface RpcSerialize { void serialize(OutputStream output, Object object) throws IOException; Object deserialize(InputStream input) throws IOException; }
/** * @filename:MessageCodecUtil.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC消息编解码接口 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support; import io.netty.buffer.ByteBuf; import java.io.IOException; public interface MessageCodecUtil { //RPC消息报文头长度4个字节 final public static int MESSAGE_LENGTH = 4; public void encode(final ByteBuf out, final Object message) throws IOException; public Object decode(byte[] body) throws IOException; }
最后我们的NettyRPC框架要能自由地支配、定制Netty的RPC服务端、客户端，采用何种序列化来进行RPC消息对象的网络传输。因此，要再抽象一个RPC消息序列化协议选择器接口（RpcSerializeFrame），对应的实现如下：
/** * @filename:RpcSerializeFrame.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC消息序序列化协议选择器接口 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support; import io.netty.channel.ChannelPipeline; public interface RpcSerializeFrame { public void select(RpcSerializeProtocol protocol, ChannelPipeline pipeline); }
现在有了上面定义的一系列的接口，现在就可以定制实现，基于Kryo、Hessian方式的RPC消息序列化、反序列化模块了。先来看下整体的类图结构：
首先是RPC消息的编码器MessageEncoder，它继承自Netty的MessageToByteEncoder编码器。主要是把RPC消息对象编码成二进制流的格式，对应实现如下：
/** * @filename:MessageEncoder.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC消息编码接口 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToByteEncoder; public class MessageEncoder extends MessageToByteEncoder<Object> { private MessageCodecUtil util = null; public MessageEncoder(final MessageCodecUtil util) { this.util = util; } protected void encode(final ChannelHandlerContext ctx, final Object msg, final ByteBuf out) throws Exception { util.encode(out, msg); } }
接下来是RPC消息的解码器MessageDecoder，它继承自Netty的ByteToMessageDecoder。主要针对二进制流反序列化成消息对象。当然了，在之前的一篇文章中我曾经提到，NettyRPC是基于TCP协议的，TCP在传输数据的过程中会出现所谓的“粘包”现象，所以我们的MessageDecoder要对RPC消息体的长度进行校验，如果不满足RPC消息报文头中指定的消息体长度，我们直接重置一下ByteBuf读索引的位置，具体可以参考如下的代码方式，进行RPC消息协议的解析：
/** * @filename:MessageDecoder.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC消息解码接口 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.ByteToMessageDecoder; import java.io.IOException; import java.util.List; import java.util.logging.Level; import java.util.logging.Logger; public class MessageDecoder extends ByteToMessageDecoder { final public static int MESSAGE_LENGTH = MessageCodecUtil.MESSAGE_LENGTH; private MessageCodecUtil util = null; public MessageDecoder(final MessageCodecUtil util) { this.util = util; } protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) { //出现粘包导致消息头长度不对，直接返回 if (in.readableBytes() < MessageDecoder.MESSAGE_LENGTH) { return; } in.markReaderIndex(); //读取消息的内容长度 int messageLength = in.readInt(); if (messageLength < 0) { ctx.close(); } //读到的消息长度和报文头的已知长度不匹配。那就重置一下ByteBuf读索引的位置 if (in.readableBytes() < messageLength) { in.resetReaderIndex(); return; } else { byte[] messageBody = new byte[messageLength]; in.readBytes(messageBody); try { Object obj = util.decode(messageBody); out.add(obj); } catch (IOException ex) { Logger.getLogger(MessageDecoder.class.getName()).log(Level.SEVERE, null, ex); } } } }
现在，我们进一步实现，利用Kryo序列化方式，对RPC消息进行编解码的模块。首先是要实现NettyRPC消息序列化接口（RpcSerialize）的方法。
/** * @filename:KryoSerialize.java * * Newland Co. Ltd. All rights reserved. * * @Description:Kryo序列化/反序列化实现 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.kryo; import newlandframework.netty.rpc.serialize.support.RpcSerialize; import com.esotericsoftware.kryo.Kryo; import com.esotericsoftware.kryo.io.Input; import com.esotericsoftware.kryo.io.Output; import com.esotericsoftware.kryo.pool.KryoPool; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class KryoSerialize implements RpcSerialize { private KryoPool pool = null; public KryoSerialize(final KryoPool pool) { this.pool = pool; } public void serialize(OutputStream output, Object object) throws IOException { Kryo kryo = pool.borrow(); Output out = new Output(output); kryo.writeClassAndObject(out, object); out.close(); pool.release(kryo); } public Object deserialize(InputStream input) throws IOException { Kryo kryo = pool.borrow(); Input in = new Input(input); Object result = kryo.readClassAndObject(in); in.close(); pool.release(kryo); return result; } }
接着利用Kryo库里面的对象池，对RPC消息对象进行编解码。首先是Kryo对象池工厂（KryoPoolFactory），这个也是我为什么选择kryo-3.0.3版本的原因了。代码如下：
/** * @filename:KryoPoolFactory.java * * Newland Co. Ltd. All rights reserved. * * @Description:Kryo对象池工厂 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.kryo; import com.esotericsoftware.kryo.Kryo; import com.esotericsoftware.kryo.pool.KryoFactory; import com.esotericsoftware.kryo.pool.KryoPool; import newlandframework.netty.rpc.model.MessageRequest; import newlandframework.netty.rpc.model.MessageResponse; import org.objenesis.strategy.StdInstantiatorStrategy; public class KryoPoolFactory { private static KryoPoolFactory poolFactory = null; private KryoFactory factory = new KryoFactory() { public Kryo create() { Kryo kryo = new Kryo(); kryo.setReferences(false); //把已知的结构注册到Kryo注册器里面，提高序列化/反序列化效率 kryo.register(MessageRequest.class); kryo.register(MessageResponse.class); kryo.setInstantiatorStrategy(new StdInstantiatorStrategy()); return kryo; } }; private KryoPool pool = new KryoPool.Builder(factory).build(); private KryoPoolFactory() { } public static KryoPool getKryoPoolInstance() { if (poolFactory == null) { synchronized (KryoPoolFactory.class) { if (poolFactory == null) { poolFactory = new KryoPoolFactory(); } } } return poolFactory.getPool(); } public KryoPool getPool() { return pool; } }
Kryo对RPC消息进行编码、解码的工具类KryoCodecUtil，实现了RPC消息编解码接口（MessageCodecUtil），具体实现方式如下：
/** * @filename:KryoCodecUtil.java * * Newland Co. Ltd. All rights reserved. * * @Description:Kryo编解码工具类 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.kryo; import com.esotericsoftware.kryo.pool.KryoPool; import io.netty.buffer.ByteBuf; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; import com.google.common.io.Closer; public class KryoCodecUtil implements MessageCodecUtil { private KryoPool pool; private static Closer closer = Closer.create(); public KryoCodecUtil(KryoPool pool) { this.pool = pool; } public void encode(final ByteBuf out, final Object message) throws IOException { try { ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); closer.register(byteArrayOutputStream); KryoSerialize kryoSerialization = new KryoSerialize(pool); kryoSerialization.serialize(byteArrayOutputStream, message); byte[] body = byteArrayOutputStream.toByteArray(); int dataLength = body.length; out.writeInt(dataLength); out.writeBytes(body); } finally { closer.close(); } } public Object decode(byte[] body) throws IOException { try { ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body); closer.register(byteArrayInputStream); KryoSerialize kryoSerialization = new KryoSerialize(pool); Object obj = kryoSerialization.deserialize(byteArrayInputStream); return obj; } finally { closer.close(); } } }
最后是，Kryo自己的编码器、解码器，其实只要调用Kryo编解码工具类（KryoCodecUtil）里面的encode、decode方法就可以了。现在贴出具体的代码：
/** * @filename:KryoDecoder.java * * Newland Co. Ltd. All rights reserved. * * @Description:Kryo解码器 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.kryo; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; import newlandframework.netty.rpc.serialize.support.MessageDecoder; public class KryoDecoder extends MessageDecoder { public KryoDecoder(MessageCodecUtil util) { super(util); } }
/** * @filename:KryoEncoder.java * * Newland Co. Ltd. All rights reserved. * * @Description:Kryo编码器 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.kryo; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; import newlandframework.netty.rpc.serialize.support.MessageEncoder; public class KryoEncoder extends MessageEncoder { public KryoEncoder(MessageCodecUtil util) { super(util); } }
最后，我们再来实现一下，利用Hessian实现RPC消息的编码、解码器代码模块。首先还是Hessian序列化/反序列化实现（HessianSerialize），它同样实现了RPC消息序列化/反序列化接口（RpcSerialize），对应的代码如下：
/** * @filename:HessianSerialize.java * * Newland Co. Ltd. All rights reserved. * * @Description:Hessian序列化/反序列化实现 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.hessian; import com.caucho.hessian.io.Hessian2Input; import com.caucho.hessian.io.Hessian2Output; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import newlandframework.netty.rpc.serialize.support.RpcSerialize; public class HessianSerialize implements RpcSerialize { public void serialize(OutputStream output, Object object) { Hessian2Output ho = new Hessian2Output(output); try { ho.startMessage(); ho.writeObject(object); ho.completeMessage(); ho.close(); output.close(); } catch (IOException e) { e.printStackTrace(); } } public Object deserialize(InputStream input) { Object result = null; try { Hessian2Input hi = new Hessian2Input(input); hi.startMessage(); result = hi.readObject(); hi.completeMessage(); hi.close(); } catch (IOException e) { e.printStackTrace(); } return result; } }
现在利用对象池（Object Pooling）技术，对Hessian序列化/反序列化类（HessianSerialize）进行池化处理，对应的代码如下：
/** * @filename:HessianSerializeFactory.java * * Newland Co. Ltd. All rights reserved. * * @Description:Hessian序列化/反序列化对象工厂池 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.hessian; import org.apache.commons.pool2.BasePooledObjectFactory; import org.apache.commons.pool2.PooledObject; import org.apache.commons.pool2.impl.DefaultPooledObject; public class HessianSerializeFactory extends BasePooledObjectFactory<HessianSerialize> { public HessianSerialize create() throws Exception { return createHessian(); } public PooledObject<HessianSerialize> wrap(HessianSerialize hessian) { return new DefaultPooledObject<HessianSerialize>(hessian); } private HessianSerialize createHessian() { return new HessianSerialize(); } }
/** * @filename:HessianSerializePool.java * * Newland Co. Ltd. All rights reserved. * * @Description:Hessian序列化/反序列化池 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.hessian; import org.apache.commons.pool2.impl.GenericObjectPool; import org.apache.commons.pool2.impl.GenericObjectPoolConfig; public class HessianSerializePool { //Netty采用Hessian序列化/反序列化的时候，为了避免重复产生对象，提高JVM内存利用率，故引入对象池技术，经过测试 //遇到高并发序列化/反序列化的场景的时候，序列化效率明显提升不少。 private GenericObjectPool<HessianSerialize> hessianPool; private static HessianSerializePool poolFactory = null; private HessianSerializePool() { hessianPool = new GenericObjectPool<HessianSerialize>(new HessianSerializeFactory()); } public static HessianSerializePool getHessianPoolInstance() { if (poolFactory == null) { synchronized (HessianSerializePool.class) { if (poolFactory == null) { poolFactory = new HessianSerializePool(); } } } return poolFactory; } //预留接口，后续可以通过Spring Property Placeholder依赖注入 public HessianSerializePool(final int maxTotal, final int minIdle, final long maxWaitMillis, final long minEvictableIdleTimeMillis) { hessianPool = new GenericObjectPool<HessianSerialize>(new HessianSerializeFactory()); GenericObjectPoolConfig config = new GenericObjectPoolConfig(); //最大池对象总数 config.setMaxTotal(maxTotal); //最小空闲数 config.setMinIdle(minIdle); //最大等待时间， 默认的值为-1，表示无限等待 config.setMaxWaitMillis(maxWaitMillis); //退出连接的最小空闲时间 默认1800000毫秒 config.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis); hessianPool.setConfig(config); } public HessianSerialize borrow() { try { return getHessianPool().borrowObject(); } catch (final Exception ex) { ex.printStackTrace(); return null; } } public void restore(final HessianSerialize object) { getHessianPool().returnObject(object); } public GenericObjectPool<HessianSerialize> getHessianPool() { return hessianPool; } }
Hessian序列化对象经过池化处理之后，我们通过Hessian编解码工具类，来“借用”Hessian序列化对象（HessianSerialize），当然了，你借出来之后，一定要还回去嘛。Hessian编解码工具类的实现方式如下：
/** * @filename:HessianCodecUtil.java * * Newland Co. Ltd. All rights reserved. * * @Description:Hessian编解码工具类 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.hessian; import com.google.common.io.Closer; import io.netty.buffer.ByteBuf; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; public class HessianCodecUtil implements MessageCodecUtil { HessianSerializePool pool = HessianSerializePool.getHessianPoolInstance(); private static Closer closer = Closer.create(); public HessianCodecUtil() { } public void encode(final ByteBuf out, final Object message) throws IOException { try { ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); closer.register(byteArrayOutputStream); HessianSerialize hessianSerialization = pool.borrow(); hessianSerialization.serialize(byteArrayOutputStream, message); byte[] body = byteArrayOutputStream.toByteArray(); int dataLength = body.length; out.writeInt(dataLength); out.writeBytes(body); pool.restore(hessianSerialization); } finally { closer.close(); } } public Object decode(byte[] body) throws IOException { try { ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body); closer.register(byteArrayInputStream); HessianSerialize hessianSerialization = pool.borrow(); Object object = hessianSerialization.deserialize(byteArrayInputStream); pool.restore(hessianSerialization); return object; } finally { closer.close(); } } }
最后Hessian对RPC消息的编码器、解码器参考实现代码如下所示：
/** * @filename:HessianDecoder.java * * Newland Co. Ltd. All rights reserved. * * @Description:Hessian解码器 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.hessian; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; import newlandframework.netty.rpc.serialize.support.MessageDecoder; public class HessianDecoder extends MessageDecoder { public HessianDecoder(MessageCodecUtil util) { super(util); } }
/** * @filename:HessianEncoder.java * * Newland Co. Ltd. All rights reserved. * * @Description:Hessian编码器 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.serialize.support.hessian; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; import newlandframework.netty.rpc.serialize.support.MessageEncoder; public class HessianEncoder extends MessageEncoder { public HessianEncoder(MessageCodecUtil util) { super(util); } }
到目前为止，NettyRPC所针对的Kryo、Hessian序列化协议模块，已经设计实现完毕，现在我们就要把这个协议，嵌入NettyRPC的核心模块包（newlandframework.netty.rpc.core），下面只给出优化调整之后的代码，其它代码模块的内容，可以参考我上一篇的文章：谈谈如何使用Netty开发实现高性能的RPC服务器。好了，我们先来看下，NettyRPC核心模块包（newlandframework.netty.rpc.core）的层次结构：
先来看下，NettyRPC服务端的实现部分。首先是，Rpc服务端管道初始化（MessageRecvChannelInitializer），跟上一版本对比，主要引入了序列化消息对象（RpcSerializeProtocol），具体实现代码如下：
/** * @filename:MessageRecvChannelInitializer.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc服务端管道初始化 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import java.util.Map; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; public class MessageRecvChannelInitializer extends ChannelInitializer<SocketChannel> { private RpcSerializeProtocol protocol; private RpcRecvSerializeFrame frame = null; MessageRecvChannelInitializer buildRpcSerializeProtocol(RpcSerializeProtocol protocol) { this.protocol = protocol; return this; } MessageRecvChannelInitializer(Map<String, Object> handlerMap) { frame = new RpcRecvSerializeFrame(handlerMap); } protected void initChannel(SocketChannel socketChannel) throws Exception { ChannelPipeline pipeline = socketChannel.pipeline(); frame.select(protocol, pipeline); } }
Rpc服务器执行模块（MessageRecvExecutor）中，默认的序列化采用Java原生本地序列化机制，并且优化了线程池异步调用的层次结构。具体代码如下：
/** * @filename:MessageRecvExecutor.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc服务器执行模块 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import com.google.common.util.concurrent.FutureCallback; import com.google.common.util.concurrent.Futures; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.ListeningExecutorService; import com.google.common.util.concurrent.MoreExecutors; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelOption; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.nio.NioServerSocketChannel; import java.nio.channels.spi.SelectorProvider; import java.util.Iterator; import java.util.Map; import java.util.Set; import java.util.concurrent.Callable; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ThreadFactory; import java.util.concurrent.ThreadPoolExecutor; import java.util.logging.Level; import newlandframework.netty.rpc.model.MessageKeyVal; import newlandframework.netty.rpc.model.MessageRequest; import newlandframework.netty.rpc.model.MessageResponse; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; import org.springframework.beans.BeansException; import org.springframework.beans.factory.InitializingBean; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; public class MessageRecvExecutor implements ApplicationContextAware, InitializingBean { private String serverAddress; //默认JKD本地序列化协议 private RpcSerializeProtocol serializeProtocol = RpcSerializeProtocol.JDKSERIALIZE; private final static String DELIMITER = ":"; private Map<String, Object> handlerMap = new ConcurrentHashMap<String, Object>(); private static ListeningExecutorService threadPoolExecutor; public MessageRecvExecutor(String serverAddress, String serializeProtocol) { this.serverAddress = serverAddress; this.serializeProtocol = Enum.valueOf(RpcSerializeProtocol.class, serializeProtocol); } public static void submit(Callable<Boolean> task, ChannelHandlerContext ctx, MessageRequest request, MessageResponse response) { if (threadPoolExecutor == null) { synchronized (MessageRecvExecutor.class) { if (threadPoolExecutor == null) { threadPoolExecutor = MoreExecutors.listeningDecorator((ThreadPoolExecutor) RpcThreadPool.getExecutor(16, -1)); } } } ListenableFuture<Boolean> listenableFuture = threadPoolExecutor.submit(task); //Netty服务端把计算结果异步返回 Futures.addCallback(listenableFuture, new FutureCallback<Boolean>() { public void onSuccess(Boolean result) { ctx.writeAndFlush(response).addListener(new ChannelFutureListener() { public void operationComplete(ChannelFuture channelFuture) throws Exception { System.out.println("RPC Server Send message-id respone:" + request.getMessageId()); } }); } public void onFailure(Throwable t) { t.printStackTrace(); } }, threadPoolExecutor); } public void setApplicationContext(ApplicationContext ctx) throws BeansException { try { MessageKeyVal keyVal = (MessageKeyVal) ctx.getBean(Class.forName("newlandframework.netty.rpc.model.MessageKeyVal")); Map<String, Object> rpcServiceObject = keyVal.getMessageKeyVal(); Set s = rpcServiceObject.entrySet(); Iterator<Map.Entry<String, Object>> it = s.iterator(); Map.Entry<String, Object> entry; while (it.hasNext()) { entry = it.next(); handlerMap.put(entry.getKey(), entry.getValue()); } } catch (ClassNotFoundException ex) { java.util.logging.Logger.getLogger(MessageRecvExecutor.class.getName()).log(Level.SEVERE, null, ex); } } public void afterPropertiesSet() throws Exception { //netty的线程池模型设置成主从线程池模式，这样可以应对高并发请求 //当然netty还支持单线程、多线程网络IO模型，可以根据业务需求灵活配置 ThreadFactory threadRpcFactory = new NamedThreadFactory("NettyRPC ThreadFactory"); //方法返回到Java虚拟机的可用的处理器数量 int parallel = Runtime.getRuntime().availableProcessors() * 2; EventLoopGroup boss = new NioEventLoopGroup(); EventLoopGroup worker = new NioEventLoopGroup(parallel, threadRpcFactory, SelectorProvider.provider()); try { ServerBootstrap bootstrap = new ServerBootstrap(); bootstrap.group(boss, worker).channel(NioServerSocketChannel.class) .childHandler(new MessageRecvChannelInitializer(handlerMap).buildRpcSerializeProtocol(serializeProtocol)) .option(ChannelOption.SO_BACKLOG, 128) .childOption(ChannelOption.SO_KEEPALIVE, true); String[] ipAddr = serverAddress.split(MessageRecvExecutor.DELIMITER); if (ipAddr.length == 2) { String host = ipAddr[0]; int port = Integer.parseInt(ipAddr[1]); ChannelFuture future = bootstrap.bind(host, port).sync(); System.out.printf("[author tangjie] Netty RPC Server start success! ip:%s port:%d protocol:%s ", host, port, serializeProtocol); future.channel().closeFuture().sync(); } else { System.out.printf("[author tangjie] Netty RPC Server start fail! "); } } finally { worker.shutdownGracefully(); boss.shutdownGracefully(); } } }
Rpc服务器消息处理（MessageRecvHandler）也跟随着调整：
/** * @filename:MessageRecvHandler.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc服务器消息处理 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import java.util.Map; import newlandframework.netty.rpc.model.MessageRequest; import newlandframework.netty.rpc.model.MessageResponse; public class MessageRecvHandler extends ChannelInboundHandlerAdapter { private final Map<String, Object> handlerMap; public MessageRecvHandler(Map<String, Object> handlerMap) { this.handlerMap = handlerMap; } public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { MessageRequest request = (MessageRequest) msg; MessageResponse response = new MessageResponse(); MessageRecvInitializeTask recvTask = new MessageRecvInitializeTask(request, response, handlerMap); //不要阻塞nio线程，复杂的业务逻辑丢给专门的线程池 MessageRecvExecutor.submit(recvTask, ctx, request, response); } public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { //网络有异常要关闭通道 ctx.close(); } }
Rpc服务器消息线程任务处理（MessageRecvInitializeTask）完成的任务也更加单纯，即根据RPC消息的请求报文，利用反射得到最终的计算结果，并把结果写入RPC应答报文结构。代码如下：
/** * @filename:MessageRecvInitializeTask.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc服务器消息线程任务处理 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import io.netty.channel.ChannelHandlerContext; import java.util.Map; import java.util.concurrent.Callable; import newlandframework.netty.rpc.model.MessageRequest; import newlandframework.netty.rpc.model.MessageResponse; import org.apache.commons.lang.reflect.MethodUtils; public class MessageRecvInitializeTask implements Callable<Boolean> { private MessageRequest request = null; private MessageResponse response = null; private Map<String, Object> handlerMap = null; private ChannelHandlerContext ctx = null; public MessageResponse getResponse() { return response; } public MessageRequest getRequest() { return request; } public void setRequest(MessageRequest request) { this.request = request; } MessageRecvInitializeTask(MessageRequest request, MessageResponse response, Map<String, Object> handlerMap) { this.request = request; this.response = response; this.handlerMap = handlerMap; this.ctx = ctx; } public Boolean call() { response.setMessageId(request.getMessageId()); try { Object result = reflect(request); response.setResult(result); return Boolean.TRUE; } catch (Throwable t) { response.setError(t.toString()); t.printStackTrace(); System.err.printf("RPC Server invoke error! "); return Boolean.FALSE; } } private Object reflect(MessageRequest request) throws Throwable { String className = request.getClassName(); Object serviceBean = handlerMap.get(className); String methodName = request.getMethodName(); Object[] parameters = request.getParameters(); return MethodUtils.invokeMethod(serviceBean, methodName, parameters); } }
刚才说到了，NettyRPC的服务端，可以选择具体的序列化协议，目前是通过硬编码方式实现。后续可以考虑，通过Spring IOC方式，依赖注入。其对应代码如下：
/** * @filename:RpcRecvSerializeFrame.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC服务端消息序列化协议框架 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import io.netty.channel.ChannelPipeline; import io.netty.handler.codec.LengthFieldBasedFrameDecoder; import io.netty.handler.codec.LengthFieldPrepender; import io.netty.handler.codec.serialization.ClassResolvers; import io.netty.handler.codec.serialization.ObjectDecoder; import io.netty.handler.codec.serialization.ObjectEncoder; import java.util.Map; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; import newlandframework.netty.rpc.serialize.support.RpcSerializeFrame; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; import newlandframework.netty.rpc.serialize.support.hessian.HessianCodecUtil; import newlandframework.netty.rpc.serialize.support.hessian.HessianDecoder; import newlandframework.netty.rpc.serialize.support.hessian.HessianEncoder; import newlandframework.netty.rpc.serialize.support.kryo.KryoCodecUtil; import newlandframework.netty.rpc.serialize.support.kryo.KryoDecoder; import newlandframework.netty.rpc.serialize.support.kryo.KryoEncoder; import newlandframework.netty.rpc.serialize.support.kryo.KryoPoolFactory; public class RpcRecvSerializeFrame implements RpcSerializeFrame { private Map<String, Object> handlerMap = null; public RpcRecvSerializeFrame(Map<String, Object> handlerMap) { this.handlerMap = handlerMap; } //后续可以优化成通过spring ioc方式注入 public void select(RpcSerializeProtocol protocol, ChannelPipeline pipeline) { switch (protocol) { case JDKSERIALIZE: { pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, MessageCodecUtil.MESSAGE_LENGTH, 0, MessageCodecUtil.MESSAGE_LENGTH)); pipeline.addLast(new LengthFieldPrepender(MessageCodecUtil.MESSAGE_LENGTH)); pipeline.addLast(new ObjectEncoder()); pipeline.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.weakCachingConcurrentResolver(this.getClass().getClassLoader()))); pipeline.addLast(new MessageRecvHandler(handlerMap)); break; } case KRYOSERIALIZE: { KryoCodecUtil util = new KryoCodecUtil(KryoPoolFactory.getKryoPoolInstance()); pipeline.addLast(new KryoEncoder(util)); pipeline.addLast(new KryoDecoder(util)); pipeline.addLast(new MessageRecvHandler(handlerMap)); break; } case HESSIANSERIALIZE: { HessianCodecUtil util = new HessianCodecUtil(); pipeline.addLast(new HessianEncoder(util)); pipeline.addLast(new HessianDecoder(util)); pipeline.addLast(new MessageRecvHandler(handlerMap)); break; } } } }
到目前为止，NettyRPC的服务端的设计实现，已经告一段落。
现在继续实现一下NettyRPC的客户端模块。其中，Rpc客户端管道初始化（MessageSendChannelInitializer）模块调整之后，同样也支持选择具体的消息序列化协议（RpcSerializeProtocol）。代码如下：
/** * @filename:MessageSendChannelInitializer.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc客户端管道初始化 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; public class MessageSendChannelInitializer extends ChannelInitializer<SocketChannel> { private RpcSerializeProtocol protocol; private RpcSendSerializeFrame frame = new RpcSendSerializeFrame(); MessageSendChannelInitializer buildRpcSerializeProtocol(RpcSerializeProtocol protocol) { this.protocol = protocol; return this; } protected void initChannel(SocketChannel socketChannel) throws Exception { ChannelPipeline pipeline = socketChannel.pipeline(); frame.select(protocol, pipeline); } }
Rpc客户端执行模块（MessageSendExecutor）代码实现如下：
/** * @filename:MessageSendExecutor.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc客户端执行模块 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import com.google.common.reflect.Reflection; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; public class MessageSendExecutor { private RpcServerLoader loader = RpcServerLoader.getInstance(); public MessageSendExecutor() { } public MessageSendExecutor(String serverAddress, RpcSerializeProtocol serializeProtocol) { loader.load(serverAddress, serializeProtocol); } public void setRpcServerLoader(String serverAddress, RpcSerializeProtocol serializeProtocol) { loader.load(serverAddress, serializeProtocol); } public void stop() { loader.unLoad(); } public static <T> T execute(Class<T> rpcInterface) { return (T) Reflection.newProxy(rpcInterface, new MessageSendProxy<T>()); } }
Rpc客户端线程任务处理（MessageSendInitializeTask），其中参数增加了协议类型（RpcSerializeProtocol），具体代码如下：
/** * @filename:MessageSendInitializeTask.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc客户端线程任务处理 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import io.netty.bootstrap.Bootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelOption; import io.netty.channel.EventLoopGroup; import io.netty.channel.socket.nio.NioSocketChannel; import java.net.InetSocketAddress; import java.util.concurrent.Callable; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; public class MessageSendInitializeTask implements Callable<Boolean> { private EventLoopGroup eventLoopGroup = null; private InetSocketAddress serverAddress = null; private RpcSerializeProtocol protocol; MessageSendInitializeTask(EventLoopGroup eventLoopGroup, InetSocketAddress serverAddress, RpcSerializeProtocol protocol) { this.eventLoopGroup = eventLoopGroup; this.serverAddress = serverAddress; this.protocol = protocol; } public Boolean call() { Bootstrap b = new Bootstrap(); b.group(eventLoopGroup) .channel(NioSocketChannel.class).option(ChannelOption.SO_KEEPALIVE, true); b.handler(new MessageSendChannelInitializer().buildRpcSerializeProtocol(protocol)); ChannelFuture channelFuture = b.connect(serverAddress); channelFuture.addListener(new ChannelFutureListener() { public void operationComplete(final ChannelFuture channelFuture) throws Exception { if (channelFuture.isSuccess()) { MessageSendHandler handler = channelFuture.channel().pipeline().get(MessageSendHandler.class); RpcServerLoader.getInstance().setMessageSendHandler(handler); } } }); return Boolean.TRUE; } }
Rpc客户端消息处理（MessageSendProxy）的实现方式调整重构之后，如下所示：
/** * @filename:MessageSendProxy.java * * Newland Co. Ltd. All rights reserved. * * @Description:Rpc客户端消息处理 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import java.lang.reflect.Method; import java.util.UUID; import newlandframework.netty.rpc.model.MessageRequest; import com.google.common.reflect.AbstractInvocationHandler; public class MessageSendProxy<T> extends AbstractInvocationHandler { public Object handleInvocation(Object proxy, Method method, Object[] args) throws Throwable { MessageRequest request = new MessageRequest(); request.setMessageId(UUID.randomUUID().toString()); request.setClassName(method.getDeclaringClass().getName()); request.setMethodName(method.getName()); request.setTypeParameters(method.getParameterTypes()); request.setParameters(args); MessageSendHandler handler = RpcServerLoader.getInstance().getMessageSendHandler(); MessageCallBack callBack = handler.sendRequest(request); return callBack.start(); } }
同样，NettyRPC的客户端也是可以选择协议类型的，必须注意的是，NettyRPC的客户端和服务端的协议类型必须一致，才能互相通信。NettyRPC的客户端消息序列化协议框架代码实现方式如下：
/** * @filename:RpcSendSerializeFrame.java * * Newland Co. Ltd. All rights reserved. * * @Description:RPC客户端消息序列化协议框架 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import io.netty.channel.ChannelPipeline; import io.netty.handler.codec.LengthFieldBasedFrameDecoder; import io.netty.handler.codec.LengthFieldPrepender; import io.netty.handler.codec.serialization.ClassResolvers; import io.netty.handler.codec.serialization.ObjectDecoder; import io.netty.handler.codec.serialization.ObjectEncoder; import newlandframework.netty.rpc.serialize.support.MessageCodecUtil; import newlandframework.netty.rpc.serialize.support.hessian.HessianCodecUtil; import newlandframework.netty.rpc.serialize.support.hessian.HessianDecoder; import newlandframework.netty.rpc.serialize.support.hessian.HessianEncoder; import newlandframework.netty.rpc.serialize.support.kryo.KryoCodecUtil; import newlandframework.netty.rpc.serialize.support.kryo.KryoDecoder; import newlandframework.netty.rpc.serialize.support.kryo.KryoEncoder; import newlandframework.netty.rpc.serialize.support.kryo.KryoPoolFactory; import newlandframework.netty.rpc.serialize.support.RpcSerializeFrame; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; public class RpcSendSerializeFrame implements RpcSerializeFrame { //后续可以优化成通过spring ioc方式注入 public void select(RpcSerializeProtocol protocol, ChannelPipeline pipeline) { switch (protocol) { case JDKSERIALIZE: { pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, MessageCodecUtil.MESSAGE_LENGTH, 0, MessageCodecUtil.MESSAGE_LENGTH)); pipeline.addLast(new LengthFieldPrepender(MessageCodecUtil.MESSAGE_LENGTH)); pipeline.addLast(new ObjectEncoder()); pipeline.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.weakCachingConcurrentResolver(this.getClass().getClassLoader()))); pipeline.addLast(new MessageSendHandler()); break; } case KRYOSERIALIZE: { KryoCodecUtil util = new KryoCodecUtil(KryoPoolFactory.getKryoPoolInstance()); pipeline.addLast(new KryoEncoder(util)); pipeline.addLast(new KryoDecoder(util)); pipeline.addLast(new MessageSendHandler()); break; } case HESSIANSERIALIZE: { HessianCodecUtil util = new HessianCodecUtil(); pipeline.addLast(new HessianEncoder(util)); pipeline.addLast(new HessianDecoder(util)); pipeline.addLast(new MessageSendHandler()); break; } } } }
最后，NettyRPC客户端，要加载NettyRPC服务端的一些上下文（Context）信息。因此，RPC服务器配置加载（RpcServerLoader）的代码重构调整如下：
/** * @filename:RpcServerLoader.java * * Newland Co. Ltd. All rights reserved. * * @Description:rpc服务器配置加载 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.core; import com.google.common.util.concurrent.FutureCallback; import com.google.common.util.concurrent.Futures; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.ListeningExecutorService; import com.google.common.util.concurrent.MoreExecutors; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import java.net.InetSocketAddress; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.locks.Condition; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock; import java.util.logging.Level; import java.util.logging.Logger; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; public class RpcServerLoader { private volatile static RpcServerLoader rpcServerLoader; private final static String DELIMITER = ":"; //默认采用Java原生序列化协议方式传输RPC消息 private RpcSerializeProtocol serializeProtocol = RpcSerializeProtocol.JDKSERIALIZE; //方法返回到Java虚拟机的可用的处理器数量 private final static int parallel = Runtime.getRuntime().availableProcessors() * 2; //netty nio线程池 private EventLoopGroup eventLoopGroup = new NioEventLoopGroup(parallel); private static ListeningExecutorService threadPoolExecutor = MoreExecutors.listeningDecorator((ThreadPoolExecutor) RpcThreadPool.getExecutor(16, -1)); private MessageSendHandler messageSendHandler = null; //等待Netty服务端链路建立通知信号 private Lock lock = new ReentrantLock(); private Condition connectStatus = lock.newCondition(); private Condition handlerStatus = lock.newCondition(); private RpcServerLoader() { } //并发双重锁定 public static RpcServerLoader getInstance() { if (rpcServerLoader == null) { synchronized (RpcServerLoader.class) { if (rpcServerLoader == null) { rpcServerLoader = new RpcServerLoader(); } } } return rpcServerLoader; } public void load(String serverAddress, RpcSerializeProtocol serializeProtocol) { String[] ipAddr = serverAddress.split(RpcServerLoader.DELIMITER); if (ipAddr.length == 2) { String host = ipAddr[0]; int port = Integer.parseInt(ipAddr[1]); final InetSocketAddress remoteAddr = new InetSocketAddress(host, port); ListenableFuture<Boolean> listenableFuture = threadPoolExecutor.submit(new MessageSendInitializeTask(eventLoopGroup, remoteAddr, serializeProtocol)); //监听线程池异步的执行结果成功与否再决定是否唤醒全部的客户端RPC线程 Futures.addCallback(listenableFuture, new FutureCallback<Boolean>() { public void onSuccess(Boolean result) { try { lock.lock(); if (messageSendHandler == null) { handlerStatus.await(); } //Futures异步回调，唤醒所有rpc等待线程 if (result == Boolean.TRUE && messageSendHandler != null) { connectStatus.signalAll(); } } catch (InterruptedException ex) { Logger.getLogger(RpcServerLoader.class.getName()).log(Level.SEVERE, null, ex); } finally { lock.unlock(); } } public void onFailure(Throwable t) { t.printStackTrace(); } }, threadPoolExecutor); } } public void setMessageSendHandler(MessageSendHandler messageInHandler) { try { lock.lock(); this.messageSendHandler = messageInHandler; handlerStatus.signal(); } finally { lock.unlock(); } } public MessageSendHandler getMessageSendHandler() throws InterruptedException { try { lock.lock(); //Netty服务端链路没有建立完毕之前，先挂起等待 if (messageSendHandler == null) { connectStatus.await(); } return messageSendHandler; } finally { lock.unlock(); } } public void unLoad() { messageSendHandler.close(); threadPoolExecutor.shutdown(); eventLoopGroup.shutdownGracefully(); } public void setSerializeProtocol(RpcSerializeProtocol serializeProtocol) { this.serializeProtocol = serializeProtocol; } }
到目前为止，NettyRPC的主要核心模块的代码，全部呈现出来了。到底经过改良重构之后，NettyRPC服务器的性能如何？还是那句话，实践是检验真理的唯一标准。现在，我们就来启动三台NettyRPC服务器进行验证。具体服务端的配置参数，参考如下：
1、Java原生本地序列化NettyRPC服务器，对应IP为：127.0.0.1:18887。
2、Kryo序列化NettyRPC服务器，对应IP为：127.0.0.1:18888。
3、Hessian序列化NettyRPC服务器，对应IP为：127.0.0.1:18889。
具体的Spring配置文件结构如下所示：
参数配置的内容如下：
rpc-server-jdknative.properties
#rpc server's ip address config rpc.server.addr=127.0.0.1:18887
rpc-server-kryo.properties
#rpc server's ip address config rpc.server.addr=127.0.0.1:18888
rpc-server-hessian.properties
#rpc server's ip address config rpc.server.addr=127.0.0.1:18889
rpc-invoke-config-jdknative.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <context:component-scan base-package="newlandframework.netty.rpc.core"/> <context:property-placeholder location="classpath:newlandframework/netty/rpc/config/rpc-server-jdknative.properties"/> <bean id="rpcbean" class="newlandframework.netty.rpc.model.MessageKeyVal"> <property name="messageKeyVal"> <map> <entry key="newlandframework.netty.rpc.servicebean.Calculate"> <ref bean="calc"/> </entry> </map> </property> </bean> <bean id="calc" class="newlandframework.netty.rpc.servicebean.CalculateImpl"/> <bean id="rpcServer" class="newlandframework.netty.rpc.core.MessageRecvExecutor"> <constructor-arg name="serverAddress" value="${rpc.server.addr}"/> <constructor-arg name="serializeProtocol" value="JDKSERIALIZE"/> </bean> </beans>
rpc-invoke-config-kryo.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <context:component-scan base-package="newlandframework.netty.rpc.core"/> <context:property-placeholder location="classpath:newlandframework/netty/rpc/config/rpc-server-kryo.properties"/> <bean id="rpcbean" class="newlandframework.netty.rpc.model.MessageKeyVal"> <property name="messageKeyVal"> <map> <entry key="newlandframework.netty.rpc.servicebean.Calculate"> <ref bean="calc"/> </entry> </map> </property> </bean> <bean id="calc" class="newlandframework.netty.rpc.servicebean.CalculateImpl"/> <bean id="rpcServer" class="newlandframework.netty.rpc.core.MessageRecvExecutor"> <constructor-arg name="serverAddress" value="${rpc.server.addr}"/> <constructor-arg name="serializeProtocol" value="KRYOSERIALIZE"/> </bean> </beans>
rpc-invoke-config-hessian.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <context:component-scan base-package="newlandframework.netty.rpc.core"/> <context:property-placeholder location="classpath:newlandframework/netty/rpc/config/rpc-server-hessian.properties"/> <bean id="rpcbean" class="newlandframework.netty.rpc.model.MessageKeyVal"> <property name="messageKeyVal"> <map> <entry key="newlandframework.netty.rpc.servicebean.Calculate"> <ref bean="calc"/> </entry> </map> </property> </bean> <bean id="calc" class="newlandframework.netty.rpc.servicebean.CalculateImpl"/> <bean id="rpcServer" class="newlandframework.netty.rpc.core.MessageRecvExecutor"> <constructor-arg name="serverAddress" value="${rpc.server.addr}"/> <constructor-arg name="serializeProtocol" value="HESSIANSERIALIZE"/> </bean> </beans>
然后，对应的NettRPC服务器启动方式参考如下：
new ClassPathXmlApplicationContext("newlandframework/netty/rpc/config/rpc-invoke-config-jdknative.xml");
new ClassPathXmlApplicationContext("newlandframework/netty/rpc/config/rpc-invoke-config-kryo.xml");
new ClassPathXmlApplicationContext("newlandframework/netty/rpc/config/rpc-invoke-config-hessian.xml");
如果一切顺利的话，在控制台上，会打印出支持Java原生序列化、Kryo序列化、Hessian序列化的NettyRPC服务器的启动信息，具体截图如下：
首先是Java原生序列化NettyRPC启动成功截图：
然后是Kryo序列化NettyRPC启动成功截图:
最后是Hessian序列化NettyRPC启动成功截图：
现在，还是跟我上一篇文章用到的并发测试用例一样，设计构造一个，瞬时值并行度1W的求和计算RPC请求，总共请求10笔，然后观察每一笔具体协议（Java原生序列化、Kryo、Hessian）的RPC消息编码、解码消耗时长（毫秒）。
测试代码如下所示：
/** * @filename:RpcParallelTest.java * * Newland Co. Ltd. All rights reserved. * * @Description:rpc并发测试代码 * @author tangjie * @version 1.0 * */ package newlandframework.netty.rpc.servicebean; import java.util.concurrent.CountDownLatch; import java.util.concurrent.TimeUnit; import newlandframework.netty.rpc.core.MessageSendExecutor; import newlandframework.netty.rpc.serialize.support.RpcSerializeProtocol; import org.apache.commons.lang.time.StopWatch; public class RpcParallelTest { public static void parallelTask(MessageSendExecutor executor, int parallel, String serverAddress, RpcSerializeProtocol protocol) throws InterruptedException { //开始计时 StopWatch sw = new StopWatch(); sw.start(); CountDownLatch signal = new CountDownLatch(1); CountDownLatch finish = new CountDownLatch(parallel); for (int index = 0; index < parallel; index++) { CalcParallelRequestThread client = new CalcParallelRequestThread(executor, signal, finish, index); new Thread(client).start(); } //10000个并发线程瞬间发起请求操作 signal.countDown(); finish.await(); sw.stop(); String tip = String.format("[%s] RPC调用总共耗时: [%s] 毫秒", protocol, sw.getTime()); System.out.println(tip); } //JDK本地序列化协议 public static void JdkNativeParallelTask(MessageSendExecutor executor, int parallel) throws InterruptedException { String serverAddress = "127.0.0.1:18887"; RpcSerializeProtocol protocol = RpcSerializeProtocol.JDKSERIALIZE; executor.setRpcServerLoader(serverAddress, protocol); RpcParallelTest.parallelTask(executor, parallel, serverAddress, protocol); TimeUnit.SECONDS.sleep(3); } //Kryo序列化协议 public static void KryoParallelTask(MessageSendExecutor executor, int parallel) throws InterruptedException { String serverAddress = "127.0.0.1:18888"; RpcSerializeProtocol protocol = RpcSerializeProtocol.KRYOSERIALIZE; executor.setRpcServerLoader(serverAddress, protocol); RpcParallelTest.parallelTask(executor, parallel, serverAddress, protocol); TimeUnit.SECONDS.sleep(3); } //Hessian序列化协议 public static void HessianParallelTask(MessageSendExecutor executor, int parallel) throws InterruptedException { String serverAddress = "127.0.0.1:18889"; RpcSerializeProtocol protocol = RpcSerializeProtocol.HESSIANSERIALIZE; executor.setRpcServerLoader(serverAddress, protocol); RpcParallelTest.parallelTask(executor, parallel, serverAddress, protocol); TimeUnit.SECONDS.sleep(3); } public static void main(String[] args) throws Exception { //并行度10000 int parallel = 10000; MessageSendExecutor executor = new MessageSendExecutor(); for (int i = 0; i < 10; i++) { JdkNativeParallelTask(executor, parallel); KryoParallelTask(executor, parallel); HessianParallelTask(executor, parallel); System.out.printf("[author tangjie] Netty RPC Server 消息协议序列化第[%d]轮并发验证结束! ", i); } executor.stop(); } }
运行截图如下：
现在，我就收集汇总一下测试数据，分析对比一下，每一种协议对RPC消息序列化/反序列化的性能（注意：由于每台计算机的配置差异，下面的测试结论可能存在出入，本次测试结果仅仅是学习交流之用！）。
经过10轮的压力测试，具体的数据如下所示：
可以很明显的发现，经过上述代码框架优化调整之后，Java原生本地序列化的处理性能，跟之前博客文章中设计实现处理性能上对比，运行效率有较大的提升（RPC消息序列化/反序列耗时更少）。Java本地序列化、Kryo序列化、Hessian序列化在10次的压力测试中，分别有1次耗时大于10S（秒）的操作。经过统计分析之后，结果如下图：
Kryo序列化、Hessian序列化的性能不分伯仲，并且总体优于Java本地序列化的性能水平。
再来看下，10轮压力测试中，Java本地序列化、Kryo序列化、Hessian序列化的耗时波动情况，如下图所示：
可以很清楚的发现，三种序列化方式分别有个“拐点”，除开这个“拐点”，三种序列化方式耗时相对来说比较平稳。但是总体而言，Kryo、Hessian序列化耗时有适当的波动，震荡相对比较明显；而Java原生序列化耗时相对来说比较平稳，没有出现频繁的震荡，但是耗时较长。
写在最后：本文是前一篇文章“谈谈如何使用Netty开发实现高性能的RPC服务器”的性能优化篇，主要从RPC消息序列化机制、对象池（Object Pooling）、多线程优化等角度，对之前设计实现的基于Netty的RPC服务器框架进行优化重构。当然目前的RPC服务器，还仅仅处于“各自为政”的状态，能不能把集群中的若干台RPC服务器，通过某种机制进行统一的分布式协调管理、以及服务调度呢？答案是肯定的，一种可行的方案就是引入Zookeeper，进行服务治理。后续有时间，我会继续加以优化改良，到时再以博客的形式，呈现给大家！由于本人的认知水平、技术能力的限制，本文中涉及的技术观点、测试数据、测试结论等等，仅限于博客园中园友们的学习交流之用。如果本人有说得不对的地方，欢迎各位园友批评指正！
洋洋洒洒地写了这么多，感谢您的耐心阅读。相信读完本篇文章，面前的您，对于利用Java开发高性能的服务端应用，又多了一份了解和自信。路漫漫其修远兮，吾将上下而求索。对于软件知识的求学探索之路没有止境，谨以此话和大家共勉之！
PS：自从在博客园发表了两篇：基于Netty开发高性能RPC服务器的文章之后，本人收到很多园友们索要源代码进行学习交流的请求。为了方便大家，本人把NettyRPC的代码开源托管到github上面，欢迎有兴趣的朋友一起学习、研究！
附上NettyRPC项目的下载路径：https://github.com/tang-jie/NettyRPC