Netty编解码技术

Netty编解码技术

编解码技术，说白了就是java序列化技术，序列化目的就两个，第一进行网络传输，第二对象持久化。
虽然可以使用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序列化没法跨语言、序列化后码流太大、序列化性能太低等等。。
主流的编解码框架:
- JBoss的Marshalling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，但又保持跟java.io.Serializable接口的兼容，同时增加了一些可调的参数和附加特性。

将对象编解码后传传输

Req

public class Req implements Serializable{    private static final long SerialVersionUID = 1L;    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;    }}

Resp

public class Resp implements Serializable{    private static final long SerialVersionUID = 1L;    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;    }}

MarshallingCodeFactory.class

public class MarshallingCodeFactory {    /**     * 创建Marshalling解码器MarshallingDecoder     * @return     */    public static MarshallingDecoder buildMarshallingDecoder(){        //首先通过Marshalling工具类的精通方法获取Marshalling实例对象 多数Serial标志创建的是java序列化工厂对象        final MarshallerFactory marshallerFactory = Marshalling.getProvidedMarshallerFactory("serial");        //创建了MarshallingConfiguration对象，配置的版本号为5        final MarshallingConfiguration configuration = new MarshallingConfiguration();        configuration.setVersion(5);        //根据marshallingFactory和Configuration创建provider        UnmarshallerProvider provider = new DefaultUnmarshallerProvider(marshallerFactory, configuration);        //构建Netty的MarshallingDecoder对象，两个参数分别为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MarshallingEncoder     * @return     */    public static MarshallingEncoder buildMarshallingEncoder(){        //首先通过Marshalling工具类的精通方法获取Marshalling实例对象 多数Serial标志创建的是java序列化工厂对象        final MarshallerFactory marshallerFactory = Marshalling.getProvidedMarshallerFactory("serial");        //创建了MarshallingConfiguration对象，配置的版本号为5        final MarshallingConfiguration configuration = new MarshallingConfiguration();        configuration.setVersion(5);        //根据marshallingFactory和Configuration创建provider        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;    }}

Client.java

public class Client {    public static void main(String[] args) throws Exception {        NioEventLoopGroup group = new NioEventLoopGroup();        Bootstrap b = new Bootstrap();        b.group(group)        .channel(NioSocketChannel.class)        .option(ChannelOption.SO_BACKLOG, 1024)        //设置日志        .handler(new LoggingHandler(LogLevel.INFO))        .handler(new ChannelInitializer<SocketChannel>() {            @Override            protected void initChannel(SocketChannel sc) throws Exception {                sc.pipeline().addLast(MarshallingCodeFactory.buildMarshallingDecoder());                sc.pipeline().addLast(MarshallingCodeFactory.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);            //读取文件            String readPath = System.getProperty("user.dir") + File.separatorChar + "sources" +  File.separatorChar + "001.jpg";            File file = new File(readPath);              FileInputStream in = new FileInputStream(file);              byte[] data = new byte[in.available()];              in.read(data);              in.close();              req.setAttachment(GzipUtil.gzip(data));            cf.channel().writeAndFlush(req);        }        cf.channel().closeFuture().sync();        group.shutdownGracefully();    }}

ClientHandler.java

public class ClientHandler extends ChannelHandlerAdapter{    @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 exceptionCaught(ChannelHandlerContext ctx, Throwable cause)            throws Exception {        ctx.close();    }}

Server.java

public class Server {    public static void main(String[] args) throws InterruptedException {        NioEventLoopGroup pGroup = new NioEventLoopGroup();        NioEventLoopGroup cGroup = new NioEventLoopGroup();        ServerBootstrap b = new ServerBootstrap();        b.group(pGroup,cGroup)        .channel(NioServerSocketChannel.class)        .childHandler(new ChannelInitializer<SocketChannel>() {            @Override            protected void initChannel(SocketChannel sc) throws Exception {                sc.pipeline().addLast(MarshallingCodeFactory.buildMarshallingDecoder());                sc.pipeline().addLast(MarshallingCodeFactory.buildMarshallingEncoder());                sc.pipeline().addLast(new ServerHandler());            }        });        ChannelFuture cf = b.bind(8765).sync();        cf.channel().closeFuture().sync();        pGroup.shutdownGracefully();        cGroup.shutdownGracefully();    }}

ServerHandler.java

public class ServerHandler extends ChannelHandlerAdapter {    @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 = GzipUtil.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);    }}