Netty编解码&粘包拆包&心跳机制&断线自动重连

<dependency>
     <groupId>com.dyuproject.protostuff</groupId>
     <artifactId>protostuff‐api</artifactId>
     <version>1.0.10</version>
</dependency>
<dependency>
    <groupId>com.dyuproject.protostuff</groupId>
    <artifactId>protostuff‐core</artifactId>
    <version>1.0.10</version>
</dependency>
<dependency>
    <groupId>com.dyuproject.protostuff</groupId>
    <artifactId>protostuff‐runtime</artifactId>
    <version>1.0.10</version>
</dependency>

import com.dyuproject.protostuff.LinkedBuffer;
import com.dyuproject.protostuff.ProtostuffIOUtil;
import com.dyuproject.protostuff.Schema;
import com.dyuproject.protostuff.runtime.RuntimeSchema;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
* protostuff 序列化工具类，基于protobuf封装
*/
public class ProtostuffUtil {

    private static Map<Class<?>, Schema<?>> cachedSchema = new ConcurrentHashMap<Class<?>, Schema<?>>();

    private static <T> Schema<T> getSchema(Class<T> clazz) {
        @SuppressWarnings("unchecked")
        Schema<T> schema = (Schema<T>) cachedSchema.get(clazz);
        if (schema == null) {
            schema = RuntimeSchema.getSchema(clazz);
            if (schema != null) {
                cachedSchema.put(clazz, schema);
            }
        }
        return schema;
    }

    /**
    * 序列化
    *
    * @param obj
    * @return
    */
    public static <T> byte[] serializer(T obj) {
        @SuppressWarnings("unchecked")
        Class<T> clazz = (Class<T>) obj.getClass();
        LinkedBuffer buffer = LinkedBuffer.allocate(LinkedBuffer.DEFAULT_BUFFER_SIZE);
        try {
            Schema<T> schema = getSchema(clazz);
            return ProtostuffIOUtil.toByteArray(obj, schema, buffer);
        } catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        } finally {
            buffer.clear();
        }
    }

    /**
    * 反序列化
    *
    * @param data
    * @param clazz
    * @return
    */
    public static <T> T deserializer(byte[] data, Class<T> clazz) {
        try {
            T obj = clazz.newInstance();
            Schema<T> schema = getSchema(clazz);
            ProtostuffIOUtil.mergeFrom(data, obj, schema);
            return obj;
        } catch (Exception e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
    }

    public static void main(String[] args) {
        byte[] userBytes = ProtostuffUtil.serializer(new User(1, "zhuge"));
        User user = ProtostuffUtil.deserializer(userBytes, User.class);
        System.out.println(user);
    }
}

//服务端代码
 public class HeartBeatServer {

     public static void main(String[] args) throws Exception {
         EventLoopGroup boss = new NioEventLoopGroup();
         EventLoopGroup worker = new NioEventLoopGroup();
         try {
             ServerBootstrap bootstrap = new ServerBootstrap();
             bootstrap.group(boss, worker)
             .channel(NioServerSocketChannel.class)
             .childHandler(new ChannelInitializer<SocketChannel>() {
                 @Override
                 protected void initChannel(SocketChannel ch) throws Exception {
                     ChannelPipeline pipeline = ch.pipeline();
                     pipeline.addLast("decoder", new StringDecoder());
                     pipeline.addLast("encoder", new StringEncoder());
                     //IdleStateHandler的readerIdleTime参数指定超过3秒还没收到客户端的连接，
                     //会触发IdleStateEvent事件并且交给下一个handler处理，下一个handler必须
                     //实现userEventTriggered方法处理对应事件
                     pipeline.addLast(new IdleStateHandler(3, 0, 0, TimeUnit.SECONDS));
                     pipeline.addLast(new HeartBeatHandler());
                 }
             });
             System.out.println("netty server start。。");
             ChannelFuture future = bootstrap.bind(9000).sync();
             future.channel().closeFuture().sync();
         } catch (Exception e) {
            e.printStackTrace();
         } finally {
             worker.shutdownGracefully();
             boss.shutdownGracefully();
         }
     }
 }

//服务端处理handler
 public class HeartBeatServerHandler extends SimpleChannelInboundHandler<String> {

     int readIdleTimes = 0;

     @Override
     protected void channelRead0(ChannelHandlerContext ctx, String s) throws Exception {
         System.out.println(" ====== > [server] message received : " + s);
         if ("Heartbeat Packet".equals(s)) {
            ctx.channel().writeAndFlush("ok");
         } else {
            System.out.println(" 其他信息处理 ... ");
         }
    }

     @Override
     public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
         IdleStateEvent event = (IdleStateEvent) evt;
         String eventType = null;
         switch (event.state()) {
             case READER_IDLE:
                 eventType = "读空闲";
                 readIdleTimes++; // 读空闲的计数加1
                 break;
             case WRITER_IDLE:
                 eventType = "写空闲";
                 // 不处理
                 break;
             case ALL_IDLE:
                 eventType = "读写空闲";
                 // 不处理
                 break;
         }
         System.out.println(ctx.channel().remoteAddress() + "超时事件：" + eventType);
         if (readIdleTimes > 3) {
             System.out.println(" [server]读空闲超过3次，关闭连接，释放更多资源");
             ctx.channel().writeAndFlush("idle close");
             ctx.channel().close();
         }
     }

     @Override
     public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.err.println("=== " + ctx.channel().remoteAddress() + " is active ===");
     }
 }

//客户端代码
 public class HeartBeatClient {
     public static void main(String[] args) throws Exception {
         EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
         try {
             Bootstrap bootstrap = new Bootstrap();
             bootstrap.group(eventLoopGroup).channel(NioSocketChannel.class)
             .handler(new ChannelInitializer<SocketChannel>() {
                 @Override
                 protected void initChannel(SocketChannel ch) throws Exception {
                     ChannelPipeline pipeline = ch.pipeline();
                     pipeline.addLast("decoder", new StringDecoder());
                     pipeline.addLast("encoder", new StringEncoder());
                     pipeline.addLast(new HeartBeatClientHandler());
                 }
             });

             System.out.println("netty client start。。");
             Channel channel = bootstrap.connect("127.0.0.1", 9000).sync().channel();
             String text = "Heartbeat Packet";
             Random random = new Random();
             while (channel.isActive()) {
                 int num = random.nextInt(10);
                 Thread.sleep(num * 1000);
                 channel.writeAndFlush(text);
             }
         } catch (Exception e) {
            e.printStackTrace();
         } finally {
            eventLoopGroup.shutdownGracefully();
         }
     }

     static class HeartBeatClientHandler extends SimpleChannelInboundHandler<String> {

         @Override
         protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
             System.out.println(" client received :" + msg);
             if (msg != null && msg.equals("idle close")) {
                 System.out.println(" 服务端关闭连接，客户端也关闭");
             ctx.channel().closeFuture();
            }
         }
     }
 }