Marshalling入門

1.1 基本概念

JBoss Marshalling是一個Java物件序列化包，對JDK預設的序列化框架進行了優化，但又保持跟java.io.Serializable介面的相容，同時增加了一些可調的引數和附加的特性，這些引數和特性可通過工廠類進行配置

1.2 Netty中使用Marshalling

對應一般業務場景而言，只需要將Marshalling編碼器和解碼器加入到ChannelPipline中，就能實現對Marshalling序列化的支援

• 新增marshalling 的 maven 依賴

<!-- https://mvnrepository.com/artifact/org.jboss.marshalling/jboss-marshalling -->
 

<dependency>
    <groupId>org.jboss.marshalling</groupId>
    <artifactId>jboss-marshalling</artifactId>
    <version>1.4.11.Final</version>
</dependency>

• 編解碼工廠類

import io.netty.handler.codec.marshalling.DefaultMarshallerProvider;
import io.netty.handler.
 
codec.marshalling.DefaultUnmarshallerProvider;
import io.netty.handler.codec.marshalling.MarshallerProvider;
import io.netty.handler.codec.marshalling.MarshallingDecoder;
import io.netty.handler.codec.marshalling.MarshallingEncoder;
import io.netty.handler.codec.marshalling.UnmarshallerProvider;

import
 
 org.jboss.marshalling.MarshallerFactory;
import org.jboss.marshalling.Marshalling;
import org.jboss.marshalling.MarshallingConfiguration;

/**
 * Marshalling工廠
 */
public final class MarshallingCodeCFactory {

    /**
     * 建立Jboss Marshalling解碼器MarshallingDecoder
     * @return MarshallingDecoder
     */
    public static MarshallingDecoder buildMarshallingDecoder() {
    	//首先通過Marshalling工具類的精通方法獲取Marshalling例項物件 引數serial標識建立的是java序列化工廠物件。
		final MarshallerFactory marshallerFactory = Marshalling.getProvidedMarshallerFactory("serial");
		//建立了MarshallingConfiguration物件，配置了版本號為5 
		final MarshallingConfiguration configuration = new MarshallingConfiguration();
		configuration.setVersion(5);
		//根據marshallerFactory和configuration建立provider
		UnmarshallerProvider provider = new DefaultUnmarshallerProvider(marshallerFactory, configuration);
		//構建Netty的MarshallingDecoder物件，倆個引數分別為provider和單個訊息序列化後的最大長度
		MarshallingDecoder decoder = new MarshallingDecoder(provider, 1024 * 1024 * 1);
		return decoder;
    }

    /**
     * 建立Jboss Marshalling編碼器MarshallingEncoder
     * @return MarshallingEncoder
     */
    public static MarshallingEncoder buildMarshallingEncoder() {
		final MarshallerFactory marshallerFactory = Marshalling.getProvidedMarshallerFactory("serial");
		final MarshallingConfiguration configuration = new MarshallingConfiguration();
		configuration.setVersion(5);
		MarshallerProvider provider = new DefaultMarshallerProvider(marshallerFactory, configuration);
		//構建Netty的MarshallingEncoder物件，MarshallingEncoder用於實現序列化介面的POJO物件序列化為二進位制陣列
		MarshallingEncoder encoder = new MarshallingEncoder(provider);
		return encoder;
    }

• 服務端，只需要給SocketChannel 新增編碼和解碼器就行了。

import io.netty.bootstrap.ServerBootstrap;
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.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

public class Server {

	public static void main(String[] args) throws Exception{
		
		EventLoopGroup pGroup = new NioEventLoopGroup();
		EventLoopGroup cGroup = new NioEventLoopGroup();
		
		ServerBootstrap b = new ServerBootstrap();
		b.group(pGroup, cGroup)
		 .channel(NioServerSocketChannel.class)
		 .option(ChannelOption.SO_BACKLOG, 1024)
		 //設定日誌
		 .handler(new LoggingHandler(LogLevel.INFO))
		 .childHandler(new ChannelInitializer<SocketChannel>() {
			protected void initChannel(SocketChannel sc) throws Exception {
				//最關鍵的兩行程式碼。即可實現序列號工作
				sc.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingDecoder());
				sc.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingEncoder());
				sc.pipeline().addLast(new ServerHandler());
			}
		});
		
		ChannelFuture cf = b.bind(8765).sync();
		
		cf.channel().closeFuture().sync();
		pGroup.shutdownGracefully();
		cGroup.shutdownGracefully();
		
	}
}

客戶端與服務端相似。文章略過客戶端以及各自的handler。最關鍵的程式碼就是下面兩句程式碼：

sc.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingDecoder());
sc.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingEncoder());

詳細的內容，可以看參考中給的案例。

參考