网络编程之每天学习一点点[day13]-----netty编解码技术

编解码技术，说白了就是java序列化传输，序列化的目的就两个：

第一个是进行网络传输，第二对象持久化。

虽然我们可以使用java进行对象序列化，netty去传输。但是java序列化的硬伤太多，比如java序列话没办法跨语言、序列化后的码流太大、序列化性能太低等等

主流的编解码框架：

JBOSS的MarsShaling包

google的Protobuf

基于Protobuf的Kyro

MessagePack框架

Jboss Marshalling是一个java对象序列化包，对jdk默认的序列化框架进行了优化，但又保留了跟java.io.serlalizable接口的兼容，同时增加了一些可调的参数和附加特性。

类库：jboss-marshalling-1.3.0、jboss-marshalling-serial-1.3.0

我们使用客户端传输的是一个req对象：

import java.io.Serializable;

public class Req implements Serializable{

	/**
	 * 
	 */
	private static final long serialVersionUID = 6673744374596339216L;
	private String id ;
	private String name ;
	private String requestMessage ;
	private byte[] attachment;
	
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getRequestMessage() {
		return requestMessage;
	}
	public void setRequestMessage(String requestMessage) {
		this.requestMessage = requestMessage;
	}
	public byte[] getAttachment() {
		return attachment;
	}
	public void setAttachment(byte[] attachment) {
		this.attachment = attachment;
	}

}

服务器端响应的对象是Resp:

import java.io.Serializable;

public class Resp implements Serializable{
	
	/**
	 * 
	 */
	private static final long serialVersionUID = -3041772672090376328L;
	private String id;
	private String name;
	private String responseMessage;
	
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getResponseMessage() {
		return responseMessage;
	}
	public void setResponseMessage(String responseMessage) {
		this.responseMessage = responseMessage;
	}
	

}

客户端和服务端的代码中都增加了marshalling的解码器和编码器

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

先看下客户端的代码

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;

import java.io.File;
import java.io.FileInputStream;

import bhz.utils.GzipUtils;

public class Client {

	
	public static void main(String[] args) throws Exception{
		
		EventLoopGroup group = new NioEventLoopGroup();
		Bootstrap b = new Bootstrap();
		b.group(group)
		 .channel(NioSocketChannel.class)
		 .handler(new ChannelInitializer<SocketChannel>() {
			@Override
			protected void initChannel(SocketChannel sc) throws Exception {
				sc.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingDecoder());
				sc.pipeline().addLast(MarshallingCodeCFactory.buildMarshallingEncoder());
				sc.pipeline().addLast(new ClientHandler());
			}
		});
		
		ChannelFuture cf = b.connect("127.0.0.1", 8765).sync();
		
		for(int i = 0; i < 5; i++ ){
			Req req = new Req();
			req.setId("" + i);
			req.setName("pro" + i);
			req.setRequestMessage("数据信息" + i);	
			String path = System.getProperty("user.dir") + File.separatorChar + "sources" +  File.separatorChar + "001.jpg";
			File file = new File(path);
	        FileInputStream in = new FileInputStream(file);  
	        byte[] data = new byte[in.available()];  
	        in.read(data);  
	        in.close(); 
			req.setAttachment(GzipUtils.gzip(data));
			cf.channel().writeAndFlush(req);
		}

		cf.channel().closeFuture().sync();
		group.shutdownGracefully();
	}
}

客户端封装了5个req对象，并且读取本地图片001.jpg,使用gzip压缩后传递给服务端。

看下客户端处理器：

import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.ReferenceCountUtil;

public class ClientHandler extends ChannelHandlerAdapter{
	
	@Override
	public void channelActive(ChannelHandlerContext ctx) throws Exception {
		
	}

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
		try {
			Resp resp = (Resp)msg;
			System.out.println("Client : " + resp.getId() + ", " + resp.getName() + ", " + resp.getResponseMessage());			
		} finally {
			ReferenceCountUtil.release(msg);
		}
	}

	@Override
	public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
		
	}

	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
		ctx.close();
	}
	
}

附上gzip工具类：

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class GzipUtils {

    public static byte[] gzip(byte[] data) throws Exception{
    	ByteArrayOutputStream bos = new ByteArrayOutputStream();
    	GZIPOutputStream gzip = new GZIPOutputStream(bos);
    	gzip.write(data);
    	gzip.finish();
    	gzip.close();
    	byte[] ret = bos.toByteArray();
    	bos.close();
    	return ret;
    }
    
    public static byte[] ungzip(byte[] data) throws Exception{
    	ByteArrayInputStream bis = new ByteArrayInputStream(data);
    	GZIPInputStream gzip = new GZIPInputStream(bis);
    	byte[] buf = new byte[1024];
    	int num = -1;
    	ByteArrayOutputStream bos = new ByteArrayOutputStream();
    	while((num = gzip.read(buf, 0 , buf.length)) != -1 ){
    		bos.write(buf, 0, num);
    	}
    	gzip.close();
    	bis.close();
    	byte[] ret = bos.toByteArray();
    	bos.flush();
    	bos.close();
    	return ret;
    }
    
    public static void main(String[] args) throws Exception{
		
    	//读取文件
    	String readPath = System.getProperty("user.dir") + File.separatorChar + "sources" +  File.separatorChar + "006.jpg";
        File file = new File(readPath);  
        FileInputStream in = new FileInputStream(file);  
        byte[] data = new byte[in.available()];  
        in.read(data);  
        in.close();  
        
        System.out.println("文件原始大小:" + data.length);
        //测试压缩
        
        byte[] ret1 = GzipUtils.gzip(data);
        System.out.println("压缩之后大小:" + ret1.length);
        
        byte[] ret2 = GzipUtils.ungzip(ret1);
        System.out.println("还原之后大小:" + ret2.length);
        
        //写出文件
        String writePath = System.getProperty("user.dir") + File.separatorChar + "receive" +  File.separatorChar + "006.jpg";
        FileOutputStream fos = new FileOutputStream(writePath);
        fos.write(ret2);
        fos.close();    	
    	
    	
	}
    
    
    
}

再看下我们的server代码：

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)
		 //设置日志
		 .handler(new LoggingHandler(LogLevel.INFO))
		 .childHandler(new ChannelInitializer<SocketChannel>() {

			protected void initChannel(SocketChannel sc) throws Exception {
				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();
		
	}
}

ServerHandler

import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

import java.io.File;
import java.io.FileOutputStream;

import bhz.utils.GzipUtils;

public class ServerHandler extends ChannelHandlerAdapter{

	@Override
	public void channelActive(ChannelHandlerContext ctx) throws Exception {

	}

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
		Req req = (Req)msg;
		System.out.println("Server : " + req.getId() + ", " + req.getName() + ", " + req.getRequestMessage());
		byte[] attachment = GzipUtils.ungzip(req.getAttachment());
		
		String path = System.getProperty("user.dir") + File.separatorChar + "receive" +  File.separatorChar + "001.jpg";
        FileOutputStream fos = new FileOutputStream(path);
        fos.write(attachment);
        fos.close();
		
		Resp resp = new Resp();
		resp.setId(req.getId());
		resp.setName("resp" + req.getId());
		resp.setResponseMessage("响应内容" + req.getId());
		ctx.writeAndFlush(resp);//.addListener(ChannelFutureListener.CLOSE);
	}

	@Override
	public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
		
	}

	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
		ctx.close();
	}

	
	
}

读取客户端发送的req，将其中的图片放置在receice文件下，封装响应报文给客户端。

看下我们的重点，MarshallingCodeCFactory：

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工厂
 * @author（jeffSheng）
 */
public final class MarshallingCodeCFactory {

    /**
     * 创建Jboss Marshalling解码器MarshallingDecoder
     * @return MarshallingDecoder
     */
    public static MarshallingDecoder buildMarshallingDecoder() {
    	//首先通过Marshalling工具类的精通方法获取Marshalling实例对象 参数serial标识创建的是java序列化工厂对象。
		final MarshallerFactory marshallerFactory = Marshalling.getProvidedMarshallerFactory("serial");
		//创建了MarshallingConfiguration对象，配置了版本号为5 
		final MarshallingConfiguration configuration = new MarshallingConfiguration();
		configuration.setVersion(5);
		//根据marshallerFactory和configuration创建provider
		UnmarshallerProvider provider = new DefaultUnmarshallerProvider(marshallerFactory, configuration);
		//构建Netty的MarshallingDecoder对象，俩个参数分别为provider和单个消息序列化后的最大长度
		MarshallingDecoder decoder = new MarshallingDecoder(provider, 1024 * 1024 * 1);
		return decoder;
    }

    /**
     * 创建Jboss Marshalling编码器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);
		//构建Netty的MarshallingEncoder对象，MarshallingEncoder用于实现序列化接口的POJO对象序列化为二进制数组
		MarshallingEncoder encoder = new MarshallingEncoder(provider);
		return encoder;
    }
}