带你手写基于 Spring 的可插拔式 RPC 框架通信协议模块

Posted paulwang92115

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在写代码之前我们先要想清楚几个问题。

  1. 我们的框架到底要实现什么功能?
    我们要实现一个远程调用的 RPC 协议。
  2. 最终实现效果是什么样的?
    我们能像调用本地服务一样调用远程的服务。
  3. 怎样实现上面的效果?
    前面几章已经给大家说了,使用动态代理,在客户端生成接口代理类使用,在代理类的 invoke 方法里面将方法参数等信息组装成 request 发给服务端,服务端需要起一个服务器一直等待接收这种消息,接收之后使用反射调
    用对应接口的实现类。

首先我们需要实现底层的通信的服务端和客户端,可以有一下几种实现:

  1. 基于 Socket 的客户端和服务端(同步阻塞式,不推荐),大家可以当作一个编程练习,整个和系统没有进行整合,纯粹练习使用。
    基于 Socket 的服务端。
    启动一个阻塞式的 socket server,加入一个线程池实现伪异步。

    public class SocketServer 
    
         private static SocketServer INSTANCE = new SocketServer();
    
         private SocketServer();
    
         public static SocketServer getInstance() 
             return INSTANCE;
         
    
         //没有核心线程数量控制的线程池,最大线程数是 Integer 的最大值,多线程实现伪异步
         ExecutorService executorService = Executors.newCachedThreadPool();
    
         /**
          * 发布服务,bio 模型
          * @param service
          * @param port
          */
         public void publiser(int port)
             try (ServerSocket serverSocket  = new ServerSocket(port);)
             
                 while (true)
                     Socket socket = serverSocket.accept();//接收请求
                     executorService.execute(new SocketHandler(socket));
                 
              catch (IOException e) 
                 e.printStackTrace();
             
         
     
    

    对应的 hanlder,使用反射调用对应的服务,并通过 sokcet 写回结果。

    public class SocketHandler implements Runnable
    
         private Socket socket;
    
         public SocketHandler(Socket socket) 
             this.socket = socket;
         
    
         @Override
         public void run() 
             try (ObjectInputStream inputStream = new ObjectInputStream(socket.getInputStream());
                  ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream());)
             
                 Object o = inputStream.readObject(); //readObject 是 java 反序列化的过程
                 System.out.println(o);
                 Object result = invoke((RpcRequest) o);
                 //写回结果
                 outputStream.writeObject(result);
                 outputStream.flush();
              catch (IOException e) 
                 e.printStackTrace();
              catch (ClassNotFoundException e) 
                 e.printStackTrace();
             
         
    
         private Object invoke(RpcRequest invocation)
    
             //根据方法名和参数类型在 service 里获取方法
             try 
                 String interFaceName = invocation.getInterfaceName();
                 Class impClass = Class.forName(invocation.getImpl());
    
                 Method method = impClass.getMethod(invocation.getMethodName(),invocation.getParamTypes());
                 String result = (String)method.invoke(impClass.newInstance(),invocation.getParams());
                 return result;
              catch (NoSuchMethodException e) 
                 e.printStackTrace();
              catch (IllegalAccessException e) 
                 e.printStackTrace();
              catch (InvocationTargetException e) 
                 e.printStackTrace();
              catch (InstantiationException e) 
                 e.printStackTrace();
              catch (ClassNotFoundException e) 
                 e.printStackTrace();
             
    
             return null;
         
     

    在看客户端,拼装参数,发送给 socket 服务端。

    public class SocketClient 
    
         private static SocketClient INSTANCE = new SocketClient();
    
         private SocketClient();
    
         public static SocketClient getInstance() 
             return INSTANCE;
         
    
         private Socket newSocket(String host, Integer port) 
             System.out.println("创建一个新的 socket 连接");
             try 
                 Socket socket = new Socket(host, port);
                 return socket;
              catch (IOException e) 
                 System.out.println("建立连接失败");
                 e.printStackTrace();
             
             return null;
         
    
         public Object sendRequest(String host, Integer port,RpcRequest rpcRequest) 
             Socket socket = newSocket(host,port);
             try (
                 ObjectOutputStream outputStream = new ObjectOutputStream(socket.getOutputStream());
                 ObjectInputStream inputStream = new ObjectInputStream(socket.getInputStream());)
             
                 outputStream.writeObject(rpcRequest);
                 outputStream.flush();
    
    
                 Object result = inputStream.readObject();
    
                 inputStream.close();
                 outputStream.close();
                 return result;
    
              catch (Exception e) 
                 e.printStackTrace();
             
             return null;
         
     
    通过上面的代码相信大家已经明白了这个流程了,就是一个客户端与服务端通信的过程,将需要调用的方法的参数传到服务端,服务端通过反射完成调用,最后返回结果给客户端。
    下面正式开始。
  2. 基于 Http 请求的客户端和基于 Tomcat 的服务端。
    基于 Tomcat 的服务端,单例模式,只有一个启动服务的 start 方法,监听到的请求通过 DispatcherServlet 处理。

    public class HttpServer 
    
         private static HttpServer INSTANCE = new HttpServer();
    
         private HttpServer()
    
         public static HttpServer getInstance()
             return INSTANCE;
         
    
    
         /**
          *
          * servlet 容器,tomcat
          * @param hostname
          * @param port
          */
    
         public void start(String hostname,Integer port)
    
             Tomcat tomcat = new Tomcat();
             Server server = tomcat.getServer();
             Service service = server.findService("Tomcat");
    
             Connector connector = new Connector();
             connector.setPort(port);
    
             Engine engine = new StandardEngine();
             engine.setDefaultHost(hostname);
    
             Host host = new StandardHost();
             host.setName(hostname);
    
             String contextPath = "";
             Context context = new StandardContext();
             context.setPath(contextPath);
             context.addLifecycleListener(new Tomcat.FixContextListener()); //声明周期监听器
    
             host.addChild(context);
             engine.addChild(host);
    
             service.setContainer(engine);
             service.addConnector(connector);
    
             tomcat.addServlet(contextPath,"dispatcher", new DispatcherServlet());
             context.addServletMappingDecoded("/*","dispatcher");
    
             try 
                 tomcat.start();
                 tomcat.getServer().await();
              catch (LifecycleException e) 
                 e.printStackTrace();
             
         
     
    

    下面来看请求分发器 DispatcherServlet 的实现,将请求派发给 HttpServletHandler 实现。

    /**
      * tomcat 是 servlet 容器,写一个 servlet
      *
      */
     public class DispatcherServlet extends HttpServlet 
    
         @Override
         protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException 
             new HttpServletHandler().handler(req,resp);
         
     

    HttpServletHandler 的实现其实就是解析 request,通过反射调用最后返回结果。

    public class HttpServletHandler
    
         public void handler(HttpServletRequest req, HttpServletResponse resp) 
    
             try(InputStream inputStream = req.getInputStream();
                 OutputStream outputStream =resp.getOutputStream();)
                 ObjectInputStream ois = new ObjectInputStream(inputStream);
                 RpcRequest invocation = (RpcRequest) ois.readObject();
    
                 // 从注册中心根据接口,找接口的实现类
                 String interFaceName = invocation.getInterfaceName();
                 Class impClass = Class.forName(invocation.getImpl());
    
    
                 Method method = impClass.getMethod(invocation.getMethodName(),invocation.getParamTypes());
                 Object result = method.invoke(impClass.newInstance(),invocation.getParams());
    
                 RpcResponse rpcResponse = new RpcResponse();
                 rpcResponse.setResponseId(invocation.getRequestId());
                 rpcResponse.setData(result);
                 IOUtils.write(toByteArray(rpcResponse),outputStream);
             catch (IOException e)
                 e.printStackTrace();
              catch (ClassNotFoundException e) 
                 e.printStackTrace();
              catch (NoSuchMethodException e) 
                 e.printStackTrace();
              catch (IllegalAccessException e) 
                 e.printStackTrace();
              catch (InvocationTargetException e) 
                 e.printStackTrace();
              catch (InstantiationException e) 
                 e.printStackTrace();
             
         
    
         public byte[] toByteArray (Object obj) 
             byte[] bytes = null;
             ByteArrayOutputStream bos = new ByteArrayOutputStream();
             try 
                 ObjectOutputStream oos = new ObjectOutputStream(bos);
                 oos.writeObject(obj);
                 oos.flush();
                 bytes = bos.toByteArray ();
                 oos.close();
                 bos.close();
              catch (IOException ex) 
                 ex.printStackTrace();
             
             return bytes;
         
    
     

    最后来看客户端的实现,通过 post 方法发送数据,最后解析服务端返回的结果。

    public class HttpClient 
    
         private static HttpClient INSTANCE = new HttpClient();
    
         private HttpClient()
    
         public static HttpClient getInstance()
             return INSTANCE;
         
    
         public Object post(String hostname, Integer port, RpcRequest invocation)
    
             try
                 URL url = new URL("http",hostname,port,"/");
                 HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
    
                 httpURLConnection.setRequestMethod("POST");
                 httpURLConnection.setDoOutput(true);
    
                 OutputStream outputStream = httpURLConnection.getOutputStream();
                 ObjectOutputStream oos = new ObjectOutputStream(outputStream);
                 oos.writeObject(invocation);
                 oos.flush();
                 oos.close();
    
                 InputStream inputStream = httpURLConnection.getInputStream();
                 RpcResponse rpcResponse =  (RpcResponse)toObject(IOUtils.toByteArray(inputStream));
                 return rpcResponse.getData();
    
    
              catch (MalformedURLException e) 
                 e.printStackTrace();
              catch (IOException e) 
                 e.printStackTrace();
             
             return null;
    
         
    
         public Object toObject (byte[] bytes) 
             Object obj = null;
             try 
                 ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
                 ObjectInputStream ois = new ObjectInputStream (bis);
                 obj = ois.readObject();
                 ois.close();
                 bis.close();
              catch (IOException ex) 
                 ex.printStackTrace();
              catch (ClassNotFoundException ex) 
                 ex.printStackTrace();
             
             return obj;
         
     
    
  3. Netty 模型的客户端和服务端。
    基于 Netty 的服务端,里面的编码器和解码器是我们自己实现的,大家可以先用我注释掉的那部分,等我们写到编码解码器的时候再替换。

    public class NettyServer 
    
         private static NettyServer INSTANCE = new NettyServer();
    
         private static Executor executor = Executors.newCachedThreadPool();
    
         private final static int MESSAGE_LENGTH = 4;
    
         private NettyServer();
    
         public static NettyServer getInstance()
             return INSTANCE;
         
    
    
         private SerializeType serializeType = SerializeType.queryByType(Configuration.getInstance().getSerialize());
    
         public static void submit(Runnable t)
             executor.execute(t);
         
    
         public void start(String host, Integer port)
             EventLoopGroup bossGroup = new NioEventLoopGroup(1);
             EventLoopGroup workerGroup = new NioEventLoopGroup();
    
             try
                 final ServerBootstrap bootstrap = new ServerBootstrap();
                 bootstrap.group(bossGroup,workerGroup)
                 .channel(NioserverSocketChannel.class)
                 .option(ChannelOption.SO_BACKLOG, 128)
                 .childOption(ChannelOption.SO_KEEPALIVE, true)
                 .childHandler(new ChannelInitializer<SocketChannel>()
    
                     @Override
                     protected void initChannel(SocketChannel arg0) throws Exception 
                         ChannelPipeline pipeline = arg0.pipeline();
                          //ObjectDecoder的基类半包解码器LengthFieldBasedFrameDecoder的报文格式保持兼容。因为底层的父类LengthFieldBasedFrameDecoder
                         //的初始化参数即为super(maxObjectSize, 0, 4, 0, 4); 
     //                  pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, NettyServer.MESSAGE_LENGTH, 0, NettyServer.MESSAGE_LENGTH));
                         //利用LengthFieldPrepender回填补充ObjectDecoder消息报文头
     //                  pipeline.addLast(new LengthFieldPrepender(NettyServer.MESSAGE_LENGTH));
     //                  pipeline.addLast(new ObjectEncoder());
                         //考虑到并发性能,采用weakCachingConcurrentResolver缓存策略。一般情况使用:cacheDisabled即可
     //                  pipeline.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.weakCachingConcurrentResolver(this.getClass().getClassLoader())));
                         //注册解码器NettyDecoderHandler
                         pipeline.addLast(new NettyDecoderHandler(RpcRequest.class, serializeType));
                         //注册编码器NettyEncoderHandler
                         pipeline.addLast(new NettyEncoderHandler(serializeType));
                         pipeline.addLast("handler", new NettyServerHandler());
    
                     
    
                 );
                 Channel channel = bootstrap.bind(host, port).sync().channel();
                 System.out.println("Server start listen at " + port);
             catch(Exception e)
                 bossGroup.shutdownGracefully();
                 workerGroup.shutdownGracefully();
             
         
    
    
     

    服务端对应的 handler,netty 都是这种 handler 模式,handler 里面也是将这个接收的 request 放入线程池中处理。

        public class NettyServerHandler extends SimpleChannelInboundHandler<RpcRequest> 
    
         private ChannelHandlerContext context;
    
    
         @Override
         protected void channelRead0(ChannelHandlerContext ctx, RpcRequest rpcRequest) throws Exception 
             System.out.println("server channelRead...");
             System.out.println(ctx.channel().remoteAddress() + "->server:" + rpcRequest.toString());
             InvokeTask it = new InvokeTask(rpcRequest,ctx);
             NettyServer.submit(it);
         
    
    
         @Override
         public void handlerAdded(ChannelHandlerContext ctx) throws Exception
             this.context = ctx;     
         
    
     

    给出 InvokeTask 的对应实现。

    public class InvokeTask implements Runnable
    
         private RpcRequest invocation;
         private ChannelHandlerContext ctx;
    
         public InvokeTask(RpcRequest invocation,ChannelHandlerContext ctx) 
             super();
             this.invocation = invocation;
             this.ctx = ctx;
         
    
    
         @Override
         public void run() 
    
             // 从注册中心根据接口,找接口的实现类
             String interFaceName = invocation.getInterfaceName();
             Class impClass = null;
             try 
                 impClass = Class.forName(invocation.getImpl());
              catch (ClassNotFoundException e) 
                 e.printStackTrace();
             
    
             Method method;
             Object result = null;
             try 
                 method = impClass.getMethod(invocation.getMethodName(),invocation.getParamTypes());
                 //这块考虑实现类,是不是应该在 spring 里面拿
                 result = method.invoke(impClass.newInstance(),invocation.getParams());
              catch (Exception e) 
                 e.printStackTrace();
             
             RpcResponse rpcResponse = new RpcResponse();
             rpcResponse.setResponseId(invocation.getRequestId());
             rpcResponse.setData(result);
             ctx.writeAndFlush(rpcResponse).addListener(new ChannelFutureListener() 
                 public void operationComplete(ChannelFuture channelFuture) throws Exception 
                     System.out.println("RPC Server Send message-id respone:" + invocation.getRequestId());
                 
             );
    
         
    
     

    再来看客户端,客户端有两种实现,一种是不能复用 handler(可以立即为 connection)的模式,这种模式并发不太高,另一种是能够复用 handler 的 handlerPool 模式。

    不能复用的模式。

    public class NettyClient 
         private static NettyClient INSTANCE = new NettyClient();
    
         private final static int parallel = Runtime.getRuntime().availableProcessors() * 2;
    
         private NettyClient();
    
         public static NettyClient getInstance()
             return INSTANCE;
         
    
         private SerializeType serializeType = SerializeType.queryByType(Configuration.getInstance().getSerialize());
    
         public void start(String host,Integer port)
    
             Bootstrap bootstrap = new Bootstrap();
             EventLoopGroup group = new NioEventLoopGroup(parallel);
    
             try
                 bootstrap.group(group)
                         .channel(NioSocketChannel.class)
                         .handler(new ChannelInitializer<SocketChannel>()
    
                             @Override
                             protected void initChannel(SocketChannel arg0) throws Exception 
                                 ChannelPipeline pipeline = arg0.pipeline();
                                 //ObjectDecoder的基类半包解码器LengthFieldBasedFrameDecoder的报文格式保持兼容。因为底层的父类LengthFieldBasedFrameDecoder
                                 //的初始化参数即为super(maxObjectSize, 0, 4, 0, 4);
     //                          pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
                                 //利用LengthFieldPrepender回填补充ObjectDecoder消息报文头
     //                          pipeline.addLast(new LengthFieldPrepender(4));
     //                          pipeline.addLast(new ObjectEncoder());
                                 //考虑到并发性能,采用weakCachingConcurrentResolver缓存策略。一般情况使用:cacheDisabled即可
     //                          pipeline.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.weakCachingConcurrentResolver(this.getClass().getClassLoader())));
                                 //注册Netty编码器
                                 System.out.println("11111111:"+serializeType.getSerializeType());
                                 pipeline.addLast(new NettyEncoderHandler(serializeType));
                                 //注册Netty解码器
                                 pipeline.addLast(new NettyDecoderHandler(RpcResponse.class, serializeType));
                                 pipeline.addLast("handler", new NettyClientHandler());
    
                             
    
                         );
                 ChannelFuture future = bootstrap.connect(host,port).sync();
             catch(Exception e)
                 group.shutdownGracefully();
             
    
    
         
     

    在看可复用的模式,固定 handler 数量,目前框架中使用的是可复用模式,上面的不可复用的没用上,为了给大家理解,没有删除。

    public class NettyChannelPoolFactory 
    
         //初始化Netty Channel阻塞队列的长度,该值为可配置信息
         private static final int channelConnectSize = 10;
    
         //Key为服务提供者地址,value为Netty Channel阻塞队列
         private static final Map<URL, ArrayBlockingQueue<Channel>> channelPoolMap = new ConcurrentHashMap<>();
    
         private static NettyChannelPoolFactory INSTANCE = new NettyChannelPoolFactory();
    
         private NettyChannelPoolFactory();
    
         public static NettyChannelPoolFactory getInstance()
             return INSTANCE;
         
    
         private List<ServiceProvider> serviceMetaDataList = new ArrayList<>();
    
         //根据配置文件里面需要调用的接口信息来初始化 channel
         public void initNettyChannelPoolFactory(Map<String, List<ServiceProvider>> providerMap)
    
             //将服务提供者信息存入serviceMetaDataList列表
             Collection<List<ServiceProvider>> collectionServiceMetaDataList = providerMap.values();
             for (List<ServiceProvider> serviceMetaDataModels : collectionServiceMetaDataList) 
                 if (CollectionUtils.isEmpty(serviceMetaDataModels)) 
                     continue;
                 
                 serviceMetaDataList.addAll(serviceMetaDataModels);
             
    
             //获取服务提供者地址列表
             Set<URL> set = new HashSet<>();
             for (ServiceProvider serviceMetaData : serviceMetaDataList) 
                 String serviceIp = serviceMetaData.getIp();
                 int servicePort = serviceMetaData.getPort();
                 URL url = new URL(serviceIp,servicePort);
                 set.add(url);
             
    
             for(URL url:set)
                 //为每个 ip端口 建立多个 channel,并且放入阻塞队列中
                 int channelSize = 0;
                 while(channelSize < channelConnectSize)
                     Channel channel = null;
                     while(channel == null)
                         channel = registerChannel(url);
                     
    
                     channelSize ++;
    
                     ArrayBlockingQueue<Channel> queue = channelPoolMap.get(url);
                     if(queue == null)
                         queue = new ArrayBlockingQueue<Channel>(channelConnectSize);
                         channelPoolMap.put(url, queue);
                     
                     queue.offer(channel);
    
                 
             
    
         
    
         public Channel registerChannel(URL url) 
             final SerializeType serializeType = SerializeType.queryByType(Configuration.getInstance().getSerialize());
             Bootstrap bootstrap = new Bootstrap();
             EventLoopGroup group = new NioEventLoopGroup(10);
    
             try
                 bootstrap.group(group)
                     .channel(NioSocketChannel.class)
                     .handler(new ChannelInitializer<SocketChannel>()
    
                     @Override
                     protected void initChannel(SocketChannel arg0) throws Exception 
                         ChannelPipeline pipeline = arg0.pipeline();
                         //ObjectDecoder的基类半包解码器LengthFieldBasedFrameDecoder的报文格式保持兼容。因为底层的父类LengthFieldBasedFrameDecoder
                         //的初始化参数即为super(maxObjectSize, 0, 4, 0, 4);
     //                  pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
                         //利用LengthFieldPrepender回填补充ObjectDecoder消息报文头
     //                  pipeline.addLast(new LengthFieldPrepender(4));
     //                  pipeline.addLast(new ObjectEncoder());
                         //考虑到并发性能,采用weakCachingConcurrentResolver缓存策略。一般情况使用:cacheDisabled即可
     //                  pipeline.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.weakCachingConcurrentResolver(this.getClass().getClassLoader())));
                         pipeline.addLast(new NettyEncoderHandler(serializeType));
                         //注册Netty解码器
                         pipeline.addLast(new NettyDecoderHandler(RpcResponse.class, serializeType));
                         pipeline.addLast("handler", new NettyClientHandler());
    
                     
    
                 );
                 ChannelFuture future = bootstrap.connect(url.getHost(),url.getPort()).sync();
                 Channel channel = future.channel();
                 //等待Netty服务端链路建立通知信号
                 final CountDownLatch connectedLatch = new CountDownLatch(1);
    
                 final List<Boolean> isSuccess = new ArrayList<>(1);
                 future.addListener(new ChannelFutureListener()
    
                     @Override
                     public void operationComplete(ChannelFuture future)
                             throws Exception 
                         if(future.isSuccess())
                             isSuccess.add(true);
                         else
                             isSuccess.add(false);
                         
                         connectedLatch.countDown();
                     
    
                 );
                 connectedLatch.await();
                 if(isSuccess.get(0))
                     return channel;
                 
             catch(Exception e)
                 group.shutdownGracefully();
                 e.printStackTrace();
             
             return null;
         
         //根据 url 获取阻塞队列
         public ArrayBlockingQueue<Channel> acqiure(URL url)
             System.out.println(channelPoolMap.toString());
             return channelPoolMap.get(url);
         
    
         //channel 使用完毕后进行回收
         public void release(ArrayBlockingQueue<Channel> queue, Channel channel, URL url)
             if(queue == null)
                 return;
             
             //需要检查 channel 是否可用,如果不可用,重新注册一个放入阻塞队列中
             if(channel == null || !channel.isActive() || !channel.isOpen()|| !channel.isWritable())
                 if (channel != null) 
                     channel.deregister().syncUninterruptibly().awaitUninterruptibly();
                     channel.closeFuture().syncUninterruptibly().awaitUninterruptibly();
                 
                 Channel c = null;
                 while(c == null)
                     c = registerChannel(url);
                 
                 queue.offer(c);
                 return;
             
             queue.offer(channel);
         
    
     

    给出对应的 handler 实现,在 channelread0 里面读取 server 端返回的信息,因为 netty 是异步的,所以需要 MessageCallBack 来实现我们的同步调用。

    public class NettyClientHandler extends SimpleChannelInboundHandler<RpcResponse> 
    
         private ChannelHandlerContext context;
    
         @Override
         public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
                 throws Exception 
             cause.printStackTrace();
             ctx.close();
         
    
         @Override
         public void channelInactive(ChannelHandlerContext ctx) throws Exception 
             System.out.println("停止时间是:"+new Date());
             System.out.println("HeartBeatClientHandler channelInactive");
         
    
         @Override
         public void channelActive(ChannelHandlerContext ctx) throws Exception 
             this.context = ctx;
             System.out.println("激活时间是:"+ctx.channel().id());
         
    
    
         @Override
         protected void channelRead0(ChannelHandlerContext channelHandlerContext, RpcResponse rpcResponse) throws Exception 
             // String res = (String)msg;
             //RpcResponse rpcResponse = (RpcResponse)msg;
             String responseId = rpcResponse.getResponseId();
             MessageCallBack callBack = ResponseHolder.getInstance().mapCallBack.get(responseId);
             if(callBack != null)
                 ResponseHolder.getInstance().mapCallBack.remove(responseId);
                 callBack.over(rpcResponse);
             
         
     

    MessageCallBack 的实现。

    public class MessageCallBack 
    
         private RpcRequest rpcRequest;
    
         private RpcResponse rpcResponse;
    
         private Lock lock = new ReentrantLock();
    
         private Condition finish = lock.newCondition();
    
         public MessageCallBack(RpcRequest request) 
             this.rpcRequest = request;
         
    
         public Object start() throws InterruptedException 
             try 
                 lock.lock();
                 //设定一下超时时间,rpc服务器太久没有相应的话,就默认返回空吧。
                 finish.await(10*1000, TimeUnit.MILLISECONDS);
                 if (this.rpcResponse != null) 
                     return this.rpcResponse.getData();
                  else 
                     return null;
                 
              finally 
                 lock.unlock();
             
         
    
         public void over(RpcResponse reponse) 
             try 
                 lock.lock();
                 this.rpcResponse = reponse;
                 finish.signal();
              finally 
                 lock.unlock();
             
         
    
     

    既然是可插拔式框架,那么底层协议一定要是可选择的,所以我们定义一个顶层接口来支持我们选择协议。
    start 方法是启动服务端,send 方法是客户端发送数据。

    public interface Procotol 
    
         void start(URL url);
         Object send(URL url, RpcRequest invocation);
     

    对应的三个协议的接口实现。
    Netty 的实现

    public class DubboProcotol implements Procotol 
         @Override
         public void start(URL url) 
             NettyServer nettyServer = NettyServer.getInstance();
             nettyServer.start(url.getHost(),url.getPort());
         
    
         @Override
         public Object send(URL url, RpcRequest invocation) 
             ArrayBlockingQueue<Channel> queue = NettyChannelPoolFactory.getInstance().acqiure(url);
             Channel channel = null;
             try 
                 channel = queue.poll(invocation.getTimeout(), TimeUnit.MILLISECONDS);
                 if(channel == null || !channel.isActive() || !channel.isOpen()|| !channel.isWritable())
                     channel = queue.poll(invocation.getTimeout(), TimeUnit.MILLISECONDS);
                     if(channel == null)
                         channel = NettyChannelPoolFactory.getInstance().registerChannel(url);
                     
                 
                 //将本次调用的信息写入Netty通道,发起异步调用
                 ChannelFuture channelFuture = channel.writeAndFlush(invocation);
                 channelFuture.syncUninterruptibly();
                 MessageCallBack callback = new MessageCallBack(invocation);
                 ResponseHolder.getInstance().mapCallBack.put(invocation.getRequestId(), callback);
                 try 
                     return callback.start();
                  catch (InterruptedException e) 
                     e.printStackTrace();
                 
                 return null;
              catch (InterruptedException e1) 
                 e1.printStackTrace();
             finally
                 System.out.println("release:"+channel.id());
                 NettyChannelPoolFactory.getInstance().release(queue, channel, url);
             
             return null;
         
     

    http 的实现

    public class HttpProcotol implements Procotol 
         @Override
         public void start(URL url) 
             HttpServer httpServer = HttpServer.getInstance();
             httpServer.start(url.getHost(),url.getPort());
         
    
         @Override
         public Object send(URL url, RpcRequest invocation) 
             HttpClient httpClient = HttpClient.getInstance();
             return httpClient.post(url.getHost(),url.getPort(),invocation);
         
     

    Socket 的实现

    public class SocketProcotol implements Procotol 
         @Override
         public void start(URL url) 
             SocketServer socketServer = SocketServer.getInstance();
             socketServer.publiser(url.getPort());
         
    
         @Override
         public Object send(URL url, RpcRequest invocation) 
             SocketClient socketClient = SocketClient.getInstance();
             return socketClient.sendRequest(url.getHost(),url.getPort(),invocation);
         
     

    这样一个可选择协议的模型就实现了,我们可已通过这个模块选择协议,并且与服务端通信。

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