netty 对象序列化传输示例

package object.server.impl;

import io.netty.bootstrap.ServerBootstrap;
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.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.serialization.ClassResolvers;
import io.netty.handler.codec.serialization.ObjectDecoder;
import io.netty.handler.codec.serialization.ObjectEncoder;

public class SubReqServer {
    public void start(int port) {
        NioEventLoopGroup workGroup = new NioEventLoopGroup();
        NioEventLoopGroup bossGroup = new NioEventLoopGroup();
        ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(bossGroup, workGroup);
        bootstrap.channel(NioServerSocketChannel.class);
        // 配置 NioServerSocketChannel 的 tcp 参数, BACKLOG 的大小
        bootstrap.option(ChannelOption.SO_BACKLOG, 1024);
        bootstrap.childHandler(new ChannelInitializer<SocketChannel>() {
            protected void initChannel(SocketChannel ch) throws Exception {
                /*
                 * 使用 weakCachingConcurrentResolver 创建线程安全的 WeakReferenceMap
                 * ,对类加载器进行缓存
                 * ,它支持多线程并发访问,当虚拟机内存不足时,会释放缓存中的内存,防止内存泄露,为了房子异常码流和解码错位导致的内存溢出
                 * ,这里将当个对象序列化之后的字节数组长度设置为1M
                 */
                ObjectDecoder objectDecoder = new ObjectDecoder(1024 * 1024,
                        ClassResolvers.weakCachingConcurrentResolver(this
                                .getClass().getClassLoader()));

                ch.pipeline().addLast(objectDecoder);
                ch.pipeline().addLast(new ObjectEncoder());
                ch.pipeline().addLast(new SubReqHandler());
            }
        });
        // 绑定端口,随后调用它的同步阻塞方法 sync 等等绑定操作成功,完成之后 Netty 会返回一个 ChannelFuture
        // 它的功能类似于的 Future,主要用于异步操作的通知回调.
        ChannelFuture channelFuture;
        try {
            channelFuture = bootstrap.bind(port).sync();
            // 等待服务端监听端口关闭,调用 sync 方法进行阻塞,等待服务端链路关闭之后 main 函数才退出.
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        SubReqServer server = new SubReqServer();
        server.start(9091);
    }
}

package object.server.impl;

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

public class SubReqHandler extends ChannelHandlerAdapter {

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

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg)
            throws Exception {

        System.out.println(msg);
        SubscriptResp sub = new SubscriptResp();
        ctx.writeAndFlush(sub);
    }

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

}

Client

package object.client.impl;

import io.netty.bootstrap.Bootstrap;
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.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.serialization.ClassResolvers;
import io.netty.handler.codec.serialization.ObjectDecoder;
import io.netty.handler.codec.serialization.ObjectEncoder;

public class SubReqClient {
    public void connect(String host, int port) {
        NioEventLoopGroup workGroup = new NioEventLoopGroup();

        Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(workGroup);
        bootstrap.channel(NioSocketChannel.class);
        bootstrap.option(ChannelOption.TCP_NODELAY, true);
        bootstrap.handler(new ChannelInitializer<SocketChannel>() {

            @Override
            protected void initChannel(SocketChannel ch) throws Exception {
                /*
                 * 禁止堆类加载器进行缓存,他在基于 OSGI 的动态模块化编程中经常使用,由于 OSGI 可以进行热部署和热升级,当某个
                 * bundle
                 * 升级后,它对应的类加载器也将一起升级,因此在动态模块化的编程过程中,很少对类加载器进行缓存,因为他随时可能会发生变化.
                 */
                ch.pipeline().addLast(
                        new ObjectDecoder(1024 >> 2, ClassResolvers
                                .cacheDisabled(getClass().getClassLoader())));
                ch.pipeline().addLast(new ObjectEncoder());
                ch.pipeline().addLast(new SubReqClientHandler());
            }
        });

        // 发起异步链接操作
        ChannelFuture future;
        try {
            future = bootstrap.connect(host, port).sync();
            // 等待客户端链路关闭
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            workGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        new SubReqClient().connect("localhost", 9091);
    }
}

ClientHandler

package object.client.impl;

import object.server.impl.SubScriptReq;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

public class SubReqClientHandler extends ChannelHandlerAdapter {

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

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        SubScriptReq req = new SubScriptReq();
        req.setSubReq(999);
        ctx.writeAndFlush(req);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg)
            throws Exception {
        System.out.println(msg);
    }

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

}

POJO

package object.server.impl;

import java.io.Serializable;

public class SubscriptResp implements Serializable {
    /**
     *
     */
    private static final long serialVersionUID = 4923081103118853877L;
    private Integer subScriptID;
    private String respCode;
    private String desc;

    public Integer getSubScriptID() {
        return subScriptID;
    }

    public void setSubScriptID(Integer subScriptID) {
        this.subScriptID = subScriptID;
    }

    public String getRespCode() {
        return respCode;
    }

    public void setRespCode(String respCode) {
        this.respCode = respCode;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    @Override
    public String toString() {
        return "SubscriptResp [subScriptID=" + subScriptID + ", respCode="
                + respCode + ", desc=" + desc + "]";
    }

}

req

package object.server.impl;

import java.io.Serializable;

public class SubScriptReq implements Serializable {
    /**
     *
     */
    private static final long serialVersionUID = 4686274228090335845L;
    private Integer subReq;
    private String userName;
    private String productName;
    private String address;

    public Integer getSubReq() {
        return subReq;
    }

    public void setSubReq(Integer subReq) {
        this.subReq = subReq;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getProductName() {
        return productName;
    }

    public void setProductName(String productName) {
        this.productName = productName;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "SubScriptReq [subReq=" + subReq + ", userName=" + userName
                + ", productName=" + productName + ", address=" + address + "]";
    }

}