此地就推行到了netty内部，通过netty自身的NioClientSocketChannel将音信发送给服务端。（这里发送在此以前有编码行为，后续会讲）
public void send(Object message, boolean sent) throws RemotingException { //重连 if (send_reconnect && !isConnected{ connect(); } //先获取Channel，是在NettyClient中实现的 Channel channel = getChannel(); //TODO getChannel返回的状态是否包含null需要改进 if (channel == null || ! channel.isConnected { throw new RemotingException(this, "message can not send, because channel is closed . url:" + getUrl; } channel是NettyChannel channel.send(message, sent);}
第三将请求参数封装成二个MuranopcInvocation实例，如下：
public void send(Object message) throws RemotingException { //NettyChannel send(message, url.getParameter(Constants.SENT_KEY, false));}
1 private volatile List<Router> routers;
2 public List<Invoker<T>> list(Invocation invocation) throws RpcException {
3 ...
4 List<Invoker<T>> invokers = doList(invocation);
5 List<Router> localRouters = this.routers; // local reference
6 if (localRouters != null && localRouters.size() > 0) {
7 for (Router router : localRouters) {
8 try {
9 if (router.getUrl() == null || router.getUrl().getParameter(Constants.RUNTIME_KEY, true)) {
10 invokers = router.route(invokers, getConsumerUrl(), invocation);
11 }
12 } catch (Throwable t) {
13 logger.error("Failed to execute router: " + getUrl() + ", cause: " + t.getMessage(), t);
14 }
15 }
16 }
17 return invokers;
18 }
Invoker<?> getInvoker(Channel channel, Invocation inv) throws RemotingException{ boolean isCallBackServiceInvoke = false; boolean isStubServiceInvoke = false; int port = channel.getLocalAddress().getPort(); String path = inv.getAttachments().get(Constants.PATH_KEY); //如果是客户端的回调服务. isStubServiceInvoke = Boolean.TRUE.toString().equals(inv.getAttachments().get(Constants.STUB_EVENT_KEY)); if (isStubServiceInvoke){ port = channel.getRemoteAddress().getPort(); } //callback isCallBackServiceInvoke = isClientSide && !isStubServiceInvoke; if(isCallBackServiceInvoke){ path = inv.getAttachments().get(Constants.PATH_KEY)+"."+inv.getAttachments().get(Constants.CALLBACK_SERVICE_KEY); inv.getAttachments().put(IS_CALLBACK_SERVICE_INVOKE, Boolean.TRUE.toString; } String serviceKey = serviceKey(port, path, inv.getAttachments().get(Constants.VERSION_KEY), inv.getAttachments().get(Constants.GROUP_KEY)); //从之前缓存的exporterMap中查找Exporter //key：dubbo.common.hello.service.HelloService:20880 DubboExporter<?> exporter = (DubboExporter<?>) exporterMap.get(serviceKey); if (exporter == null) throw new RemotingException; //得到Invoker，返回 return exporter.getInvoker();}
第3实施doList(invocation)方法赢得出List<Invoker<T>>，之后选用router循环过滤，最终回来过滤后的List<Invoker<T>>。
买主端的DubboInvoker发起请求后，后续的逻辑是异步的或是钦赐超时时间内阻塞的，直到获得响应结果后，继续执行DubboInvoker中逻辑。
1 public class InvokerInvocationHandler implements InvocationHandler {
2 private final Invoker<?> invoker;//MockClusterInvoker实例
3
4 public InvokerInvocationHandler(Invoker<?> handler) {
5 this.invoker = handler;
6 }
7
8 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
9 String methodName = method.getName();
10 Class<?>[] parameterTypes = method.getParameterTypes();
11 if (method.getDeclaringClass() == Object.class) {
12 return method.invoke(invoker, args);
13 }
14 if ("toString".equals(methodName) && parameterTypes.length == 0) {
15 return invoker.toString();
16 }
17 if ("hashCode".equals(methodName) && parameterTypes.length == 0) {
18 return invoker.hashCode();
19 }
20 if ("equals".equals(methodName) && parameterTypes.length == 1) {
21 return invoker.equals(args[0]);
22 }
23 return invoker.invoke(new RpcInvocation(method, args)).recreate();
24 }
25 }
Result result =
invoker.invoke(invocation);调用并回到结果，会率先进入InvokerWrapper，然后进入ListenerInvokerWrapper的invoke方法，接着进入AbstractInvoker的invoke：
RandomLoadBalance.doSelect
此间会去运转新线程执行Channel伊夫ntRunnable的run方法，接着去调用DecodeHandler的received方法：
1 public void send(Object message, boolean sent) throws RemotingException {
2 if (send_reconnect && !isConnected()) {
3 connect();
4 }
5 Channel channel = getChannel();//NettyChannel
6 //TODO getChannel返回的状态是否包含null需要改进
7 if (channel == null || !channel.isConnected()) {
8 throw new RemotingException(this, "message can not send, because channel is closed . url:" + getUrl());
9 }
10 channel.send(message, sent);
11 }
注意：
在八.二创设客户端源码解析中我们看到最终收获的demoService是二个proxy0代理对象。以后来分析第1行代码。
public Result invoke(Invocation inv) throws RpcException { if(destroyed) { throw new RpcException; } //转成RpcInvocation RpcInvocation invocation = (RpcInvocation) inv; invocation.setInvoker; if (attachment != null && attachment.size { invocation.addAttachmentsIfAbsent(attachment); } Map<String, String> context = RpcContext.getContext().getAttachments(); if (context != null) { invocation.addAttachmentsIfAbsent; } if .getMethodParameter(invocation.getMethodName(), Constants.ASYNC_KEY, false)){ invocation.setAttachment(Constants.ASYNC_KEY, Boolean.TRUE.toString; } //异步的话，需要添加id RpcUtils.attachInvocationIdIfAsync, invocation); try { //这里是DubboInvoker return doInvoke(invocation); } catch (InvocationTargetException e) { } }
一 客户端请求总体流程
public void received(Channel channel, Object message) throws RemotingException { //获取线程池执行 ExecutorService cexecutor = getExecutorService(); try { //handler是DecodeHandler cexecutor.execute(new ChannelEventRunnable(channel, handler, ChannelState.RECEIVED, message)); } catch (Throwable t) { }}
1 public Result doInvoke(Invocation invocation, final List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
2 List<Invoker<T>> copyinvokers = invokers;
3 checkInvokers(copyinvokers, invocation);
4 int len = getUrl().getMethodParameter(invocation.getMethodName(), Constants.RETRIES_KEY, Constants.DEFAULT_RETRIES) + 1;//默认是2+1次
5 if (len <= 0) {
6 len = 1;
7 }
8 // retry loop.
9 RpcException le = null; // last exception.
10 List<Invoker<T>> invoked = new ArrayList<Invoker<T>>(copyinvokers.size()); // invoked invokers.
11 Set<String> providers = new HashSet<String>(len);
12 for (int i = 0; i < len; i++) {
13 //重试时，进行重新选择，避免重试时invoker列表已发生变化.
14 //注意：如果列表发生了变化，那么invoked判断会失效，因为invoker示例已经改变
15 if (i > 0) {
16 checkWhetherDestroyed();
17 copyinvokers = list(invocation);
18 //重新检查一下
19 checkInvokers(copyinvokers, invocation);
20 }
21 Invoker<T> invoker = select(loadbalance, invocation, copyinvokers, invoked);
22 invoked.add(invoker);
23 RpcContext.getContext().setInvokers((List) invoked);
24 try {
25 Result result = invoker.invoke(invocation);
26 ...
27 return result;
28 } catch (RpcException e) {
29 if (e.isBiz()) { // biz exception.
30 throw e;
31 }
32 le = e;
33 } catch (Throwable e) {
34 le = new RpcException(e.getMessage(), e);
35 } finally {
36 providers.add(invoker.getUrl().getAddress());
37 }
38 }
39 throw new RpcException(le ...);
40 }
public Result doInvoke(Invocation invocation, final List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException { List<Invoker<T>> copyinvokers = invokers; //检查invokers是否为空 checkInvokers(copyinvokers, invocation); //重试次数 int len = getUrl().getMethodParameter(invocation.getMethodName(), Constants.RETRIES_KEY, Constants.DEFAULT_RETRIES) + 1; if (len <= 0) { len = 1; } // retry loop. RpcException le = null; // last exception. //已经调用过的invoker List<Invoker<T>> invoked = new ArrayList<Invoker<T>>(copyinvokers.size; // invoked invokers. Set<String> providers = new HashSet<String>; for (int i = 0; i < len; i++) { //重试时，进行重新选择，避免重试时invoker列表已发生变化. //注意：如果列表发生了变化，那么invoked判断会失效，因为invoker示例已经改变 if { checkWheatherDestoried(); copyinvokers = list(invocation); //重新检查一下 checkInvokers(copyinvokers, invocation); } //使用负载均衡选择invoker.（负载均衡咱先不做解释） Invoker<T> invoker = select(loadbalance, invocation, copyinvokers, invoked); invoked.add; //添加到以调用过的列表中 RpcContext.getContext().setInvokersinvoked); try { //开始调用，返回结果 Result result = invoker.invoke(invocation); return result; } catch (RpcException e) {。。。 } finally { providers.add(invoker.getUrl().getAddress; } } throw new RpcException;}
1 DemoService demoService = (DemoService) context.getBean("demoService"); // 获取远程服务代理
2 String hello = demoService.sayHello("world"); // 执行远程方法
进入MultiMessageHandler：
2 源码分析
进去拍卖response的decode方法，进行解码response：
ReferenceCountExchangeClient.request
进入MultiMessageHandler的received方法：
1 protected Invoker<T> select(LoadBalance loadbalance, Invocation invocation, List<Invoker<T>> invokers, List<Invoker<T>> selected) throws RpcException {
2 ...
3 Invoker<T> invoker = doselect(loadbalance, invocation, invokers, selected);
4 ..
5 return invoker;
6 }
7
8 private Invoker<T> doselect(LoadBalance loadbalance, Invocation invocation, List<Invoker<T>> invokers, List<Invoker<T>> selected) throws RpcException {
9 if (invokers == null || invokers.size() == 0)
10 return null;
11 if (invokers.size() == 1)
12 return invokers.get(0);
13 // 如果只有两个invoker，并且其中一个已经有至少一个被选过了，退化成轮循
14 if (invokers.size() == 2 && selected != null && selected.size() > 0) {
15 return selected.get(0) == invokers.get(0) ? invokers.get(1) : invokers.get(0);
16 }
17 Invoker<T> invoker = loadbalance.select(invokers, getUrl(), invocation);
18
19 //如果 selected中包含（优先判断） 或者 不可用&&availablecheck=true 则重试.
20 if ((selected != null && selected.contains(invoker))
21 || (!invoker.isAvailable() && getUrl() != null && availablecheck)) {
22 try {
23 Invoker<T> rinvoker = reselect(loadbalance, invocation, invokers, selected, availablecheck);
24 ...
25 } catch (Throwable t) {
26 ...
27 }
28 }
29 return invoker;
30 }
随之会跻身HeaderExchangerHandler.received () 方法：
1 ExchangeClient[] clients = [ReferenceCountExchangeClient实例]//如果设置了多条连接，此处有多个client
对于异步请求时，消费者获得Future，别的逻辑均是异步的。
//代理发出请求
proxy0.sayHello(String paramString)
-->InvokerInvocationHandler.invoke(Object proxy, Method method, Object[] args)
-->new RpcInvocation(method, args)
-->MockClusterInvoker.invoke(Invocation invocation)//服务降级的地方
//ClusterInvoker将多个Invoker伪装成一个集群版的Invoker
-->AbstractClusterInvoker.invoke(final Invocation invocation)
//获取Invokers
-->list(Invocation invocation)
-->AbstractDirectory.list(Invocation invocation)
-->RegistryDirectory.doList(Invocation invocation)//从Map<String, List<Invoker<T>>> methodInvokerMap中获取key为sayHello的List<Invoker<T>>
-->MockInvokersSelector.getNormalInvokers(final List<Invoker<T>> invokers)//对上述的List<Invoker<T>>再进行一次过滤（这里比如说过滤出所有协议为mock的Invoker，如果一个也没有就全部返回），这就是router的作用
//获取负载均衡器
-->loadbalance = ExtensionLoader.getExtensionLoader(LoadBalance.class).getExtension(invokers.get(0).getUrl()
.getMethodParameter(invocation.getMethodName(), Constants.LOADBALANCE_KEY, Constants.DEFAULT_LOADBALANCE))//默认为random
-->RpcUtils.attachInvocationIdIfAsync(getUrl(), invocation)//异步操作添加invocationID
-->FailoverClusterInvoker.doInvoke(Invocation invocation, final List<Invoker<T>> invokers, LoadBalance loadbalance)
//使用负载均衡器选择一个Invoker出来：RegistryDirectory$InvokerDelegete实例
-->AbstractClusterInvoker.select(LoadBalance loadbalance, Invocation invocation, List<Invoker<T>> invokers, List<Invoker<T>> selected)
-->doselect(LoadBalance loadbalance, Invocation invocation, List<Invoker<T>> invokers, List<Invoker<T>> selected)
-->AbstractLoadBalance.select(List<Invoker<T>> invokers, URL url, Invocation invocation)
-->RandomLoadBalance.doSelect(List<Invoker<T>> invokers, URL url, Invocation invocation)
//执行listener和filter链
-->ListenerInvokerWrapper.invoke
-->ConsumerContextFilter.invoke(Invoker<?> invoker, Invocation invocation)//设置一些RpcContext属性，并且设置invocation中的invoker属性
-->FutureFilter.invoke(Invocation invocation)
-->MonitorFilter.invoke(Invocation invocation)//monitor在这里收集数据
-->AbstractInvoker.invoke(Invocation inv)//重新设置了invocation中的invoker属性和attachment属性
-->DubboInvoker.doInvoke(final Invocation invocation)
//获取ExchangeClient进行消息的发送
-->ReferenceCountExchangeClient.request(Object request, int timeout)
-->HeaderExchangeClient.request(Object request, int timeout)
-->HeaderExchangeChannel.request(Object request, int timeout)
-->AbstractClient.send(Object message, boolean sent)//NettyClient的父类
-->getChannel()//NettyChannel实例，其内部channel实例=NioClientSocketChannel实例
-->NettyChannel.send(Object message, boolean sent)
-->NioClientSocketChannel.write(Object message)//已经是netty的东西了，这里的message=Request实例：最重要的是RpcInvocation [methodName=sayHello, parameterTypes=[class java.lang.String], arguments=[world], attachments={path=com.alibaba.dubbo.demo.DemoService, interface=com.alibaba.dubbo.demo.DemoService, version=0.0.0}]
//子类处理，接着是AbstractClient执行发送public void send(Object message) throws RemotingException { send(message, url.getParameter(Constants.SENT_KEY, false));}
1 private final Directory<T> directory;//RegistryDirectory
2 private final Invoker<T> invoker;//FailoverClusterInvoker
3
4 /**
5 * 这里实际上会根据配置的mock参数来做服务降级：
6 * 1 如果没有配置mock参数或者mock=false，则进行远程调用；
7 * 2 如果配置了mock=force:return null，则直接返回null，不进行远程调用；
8 * 3 如果配置了mock=fail:return null，先进行远程调用，失败了在进行mock调用。
9 */
10 public Result invoke(Invocation invocation) throws RpcException {
11 Result result = null;
12 //sayHello.mock->mock->default.mock
13 String value = directory.getUrl().getMethodParameter(invocation.getMethodName(), Constants.MOCK_KEY, Boolean.FALSE.toString()).trim();
14 if (value.length() == 0 || value.equalsIgnoreCase("false")) {
15 //no mock
16 result = this.invoker.invoke(invocation);
17 } else if (value.startsWith("force")) {
18 if (logger.isWarnEnabled()) {
19 logger.info("force-mock: " + invocation.getMethodName() + " force-mock enabled , url : " + directory.getUrl());
20 }
21 //force:direct mock
22 result = doMockInvoke(invocation, null);
23 } else {
24 //fail-mock
25 try {
26 result = this.invoker.invoke(invocation);
27 } catch (RpcException e) {
28 if (e.isBiz()) {
29 throw e;
30 } else {
31 if (logger.isWarnEnabled()) {
32 logger.info("fail-mock: " + invocation.getMethodName() + " fail-mock enabled , url : " + directory.getUrl(), e);
33 }
34 result = doMockInvoke(invocation, e);
35 }
36 }
37 }
38 return result;
39 }
这一步设置response到买主请求的Future中，以供消费者通过DefaultFuture.get()取得提供者的响应，此为同步转异步首要一步，且请求超时也由DefaultFuture控制。
首先使用负载均衡器获取四个RegistryDirectory$InvokerDelegete实例，然后使用选出的RegistryDirectory$InvokerDelegete.invoke举办呼吁发送。
public Result invoke(final Invocation invocation) throws RpcException { //检查是否被销毁 checkWheatherDestoried(); LoadBalance loadbalance; //根据invocation中的参数来获取所有的invoker列表 List<Invoker<T>> invokers = list(invocation); if (invokers != null && invokers.size { //我们没有配置负载均衡的参数，默认使用random //这里得到的是RandomLoadBalance loadbalance = ExtensionLoader.getExtensionLoader(LoadBalance.class).getExtension(invokers.get.getUrl() .getMethodParameter(invocation.getMethodName(),Constants.LOADBALANCE_KEY, Constants.DEFAULT_LOADBALANCE)); } else { loadbalance = ExtensionLoader.getExtensionLoader(LoadBalance.class).getExtension(Constants.DEFAULT_LOADBALANCE); } //如果是异步操作默认添加invocation id RpcUtils.attachInvocationIdIfAsync, invocation); //这里是子类实现，FailoverClusterInvoker中，执行调用 return doInvoke(invocation, invokers, loadbalance);}
1 private final ExchangeClient[] clients;
2
3 protected Result doInvoke(final Invocation invocation) throws Throwable {
4 RpcInvocation inv = (RpcInvocation) invocation;
5 final String methodName = RpcUtils.getMethodName(invocation);
6 inv.setAttachment(Constants.PATH_KEY, getUrl().getPath());
7 inv.setAttachment(Constants.VERSION_KEY, version);
8
9 ExchangeClient currentClient;
10 if (clients.length == 1) {
11 currentClient = clients[0];//单一长连接。默认
12 } else {
13 currentClient = clients[index.getAndIncrement() % clients.length];
14 }
15 try {
16 boolean isAsync = RpcUtils.isAsync(getUrl(), invocation);//是否异步
17 boolean isOneway = RpcUtils.isOneway(getUrl(), invocation);//是否没有返回值
18 int timeout = getUrl().getMethodParameter(methodName, Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT);
19 if (isOneway) {
20 boolean isSent = getUrl().getMethodParameter(methodName, Constants.SENT_KEY, false);
21 currentClient.send(inv, isSent);
22 RpcContext.getContext().setFuture(null);
23 return new RpcResult();
24 } else if (isAsync) {
25 ResponseFuture future = currentClient.request(inv, timeout);
26 RpcContext.getContext().setFuture(new FutureAdapter<Object>(future));
27 return new RpcResult();
28 } else {
29 RpcContext.getContext().setFuture(null);
30 return (Result) currentClient.request(inv, timeout).get();
31 }
32 } catch (TimeoutException e) {
33 throw new RpcException(RpcException.TIMEOUT_EXCEPTION, "Invoke remote method timeout. method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e);
34 } catch (RemotingException e) {
35 throw new RpcException(RpcException.NETWORK_EXCEPTION, "Failed to invoke remote method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e);
36 }
37 }
先看下new
翼虎pcInvocation，Invocation是会话域，它富有调用进度中的变量，比如方法名，参数类型等。接着是invoker.invoke()，那里invoker是MockClusterInvoker，进入MockClusterInvoker.invoker()：
1 public String sayHello(String paramString) {
2 Object[] arrayOfObject = new Object[1];
3 arrayOfObject[0] = paramString;
4 Object localObject = null;
5 try {
6 localObject = this.handler.invoke(this, DemoService.class.getMethod("sayHello"), arrayOfObject);
7 } catch (Throwable e) {
8 // TODO Auto-generated catch block
9 e.printStackTrace();
10 }
11 return (String) localObject;
12 }
public ResponseFuture request(Object request, int timeout) throws RemotingException { //这里的Channel是HeaderExchangeChannel return channel.request(request, timeout);}
1 public List<Invoker<T>> doList(Invocation invocation) {
2 ...
3 List<Invoker<T>> invokers = null;
4 Map<String, List<Invoker<T>>> localMethodInvokerMap = this.methodInvokerMap; // local reference
5 if (localMethodInvokerMap != null && localMethodInvokerMap.size() > 0) {
6 String methodName = RpcUtils.getMethodName(invocation);
7 Object[] args = RpcUtils.getArguments(invocation);
8 if (args != null && args.length > 0 && args[0] != null
9 && (args[0] instanceof String || args[0].getClass().isEnum())) {
10 invokers = localMethodInvokerMap.get(methodName + "." + args[0]); // 可根据第一个参数枚举路由 sayHello.world
11 }
12 if (invokers == null) {
13 invokers = localMethodInvokerMap.get(methodName);
14 }
15 if (invokers == null) {
16 invokers = localMethodInvokerMap.get(Constants.ANY_VALUE);
17 }
18 if (invokers == null) {
19 Iterator<List<Invoker<T>>> iterator = localMethodInvokerMap.values().iterator();
20 if (iterator.hasNext()) {
21 invokers = iterator.next();
22 }
23 }
24 }
25 return invokers == null ? new ArrayList<Invoker<T>>(0) : invokers;
26 }
解析完请求，构造完响应新闻，就从头发送响应了,channel.send;，先经过AbstractPeer:
RegistryDirectory.doList(invocation)
public void received(Channel ch, Object msg) throws RemotingException { if { return; } //这里是MultiMessageHandler handler.received;}
先是来看proxy0.sayHello
public void received(Channel channel, Object message) throws RemotingException { if (message instanceof Decodeable) { decode; } if (message instanceof Request) { decode(message).getData; } //这里进行response类型的处理 if (message instanceof Response) { decode( (message).getResult; } handler.received(channel, message);}
来看一下客户端请求代码：
public Object reply(ExchangeChannel channel, Object message) throws RemotingException { if (message instanceof Invocation) { //Invocation中保存着方法名等 Invocation inv = (Invocation) message; //获取Invoker Invoker<?> invoker = getInvoker(channel, inv); //如果是callback 需要处理高版本调用低版本的问题 if (Boolean.TRUE.toString().equals(inv.getAttachments().get(IS_CALLBACK_SERVICE_INVOKE))){ String methodsStr = invoker.getUrl().getParameters().get("methods"); boolean hasMethod = false; if (methodsStr == null || methodsStr.indexOf == -1){ hasMethod = inv.getMethodName().equals(methodsStr); } else { String[] methods = methodsStr.split; for (String method : methods){ if (inv.getMethodName().equals{ hasMethod = true; break; } } } if (!hasMethod){ return null; } } RpcContext.getContext().setRemoteAddress(channel.getRemoteAddress; //执行调用，然后返回结果 return invoker.invoke; } throw new RemotingException; }
最后来看RegistryDirectory$InvokerDelegete.invoke，该情势其实在其父类InvokerWrapper中：
先经过AbstractPeer的received方法：
一体化流程：
劳动提供者端接收到消费者端的请求并拍卖现在，重返给消费者端，消费者这边接受响应的入口跟提供者差不多，也是NettyCodec艾达pter.messageReceived()，经过解码，到NettyHandler.messageReceived()处理：
-->String methodName=sayHello
-->Class<?>[] parameterTypes=[class java.lang.String]
-->Object[] arguments=[world]
-->Map<String, String> attachments={}
public void received(Channel channel, Object message) throws RemotingException { if (message instanceof MultiMessage) { MultiMessage list = (MultiMessage)message; for(Object obj : list) { handler.received(channel, obj); } } else { //HeartbeatHandler handler.received(channel, message); }}
其中Map<String, List<Invoker<T>>>
methodInvokerMap在捌.二创设客户端源码解析已经先河化好了：
DubboInvoker.doInvoke()：
先是是获得一个List<Invoker<T>>，之后收获二个LoadBalance，最终调用doInvoke实行调用。
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception { NettyChannel channel = NettyChannel.getOrAddChannel(ctx.getChannel(), url, handler); try { //NettyClient handler.received(channel, e.getMessage; } finally { NettyChannel.removeChannelIfDisconnected(ctx.getChannel; }}
doInvoke(Invocation invocation, final List<Invoker<T>>
invokers, LoadBalance loadbalance)：
public ResponseFuture request(Object request, int timeout) throws RemotingException { if { throw new RemotingException; } //创建一个请求头 Request req = new Request(); req.setVersion; req.setTwoWay; //这里request参数里面保存着 //methodName = "sayHello" //parameterTypes = {Class[0]@2814} //arguments = {Object[0]@2768} //attachments = {HashMap@2822} size = 4 //invoker = {DubboInvoker@2658} req.setData; DefaultFuture future = new DefaultFuture(channel, req, timeout); try{ //这里的channel是NettyClient //发送请求 channel.send; }catch (RemotingException e) { future.cancel(); throw e; } return future;}
先是来看经过RegistryDirectory.list(Invocation
invocation)，该方法在RegistryDirectory的父类AbstractDirectory中：
先看下处理请求，并组织响应音讯：
HeaderExchangeChannel.request
handleResponse方法：
留意：那里能够做劳动降级，后续会说。
此起彼伏进入AllChannelHandler的received方法：
从此以往调用FailoverClusterInvoker.invoke方法，该格局在其父类AbstractClusterInvoker中，
然后正是return currentClient.request(inv,
timeout).get();在DubboInvoker中，那里继续执行，然后实施Filter，最后回来到InvokerInvocationHandler.invoker()方法中，方法获得调用结果，截至！
1 protected final Directory<T> directory;//RegistryDirectory
2
3 public Result invoke(final Invocation invocation) throws RpcException {
4 ...
5 LoadBalance loadbalance;
6
7 List<Invoker<T>> invokers = list(invocation);
8 if (invokers != null && invokers.size() > 0) {
9 loadbalance = ExtensionLoader.getExtensionLoader(LoadBalance.class).getExtension(invokers.get(0).getUrl()
10 .getMethodParameter(invocation.getMethodName(), Constants.LOADBALANCE_KEY, Constants.DEFAULT_LOADBALANCE));
11 } else {
12 loadbalance = ExtensionLoader.getExtensionLoader(LoadBalance.class).getExtension(Constants.DEFAULT_LOADBALANCE);
13 }
14 RpcUtils.attachInvocationIdIfAsync(getUrl(), invocation);//异步调用加调用ID
15 return doInvoke(invocation, invokers, loadbalance);
16 }
17
18 protected List<Invoker<T>> list(Invocation invocation) throws RpcException {
19 List<Invoker<T>> invokers = directory.list(invocation);
20 return invokers;
21 }
public void received(Channel ch, Object msg) throws RemotingException { if { return; } //MultiMessageHandler handler.received;}
其中ExchangeClient[] clients在八.2创设客户端源码解析曾经被开端化好了：
跻身NettyChannel中，进行响应新闻的出殡：
- 将呼吁参数（方法名，方法参数类型，方法参数值，服务名，附加参数）封装成二个Invocation
- 叠加参数中的path：即接口名，将会用于服务端接收请求音讯后从exportMap中选择Exporter实例
- 形式名，方法参数类型，方法参数值：将用于JavassistProxyFactory$AbstractProxyInvoker执行相应的主意
- 选拔Directory从Map<String, List<Invoker<T>>>
methodInvokerMap中获取key为sayHello（内定方法名）的List<Invoker<T>> - 使用Router对上述的List<Invoker<T>>再开始展览1遍过滤，得到subList
- 运用LoadBalancer从subList中再取得四个Invoker，实际上是InvokerDelegete实例
- 采纳InvokerDelegete实例执行真正的DubboInvoker的listener和filter链，然后实施到真正的DubboInvoker
- DubboInvoker使用NettyClient向服务端发出了请求
public void received(Channel channel, Object message) throws RemotingException { channel.setAttribute(KEY_READ_TIMESTAMP, System.currentTimeMillis; ExchangeChannel exchangeChannel = HeaderExchangeChannel.getOrAddChannel; try { if (message instanceof Request) { Request request = message; if (request.isEvent { handlerEvent(channel, request); } else { if (request.isTwoWay { Response response = handleRequest(exchangeChannel, request); channel.send; } else { handler.received(exchangeChannel, request.getData; } } } else if (message instanceof Response) { //这里处理response消息 handleResponse(channel, message); } else if (message instanceof String) { if (isClientSide { Exception } else { String echo = handler.telnet(channel, message); if (echo != null && echo.length { channel.send; } } } else { handler.received(exchangeChannel, message); } } finally { HeaderExchangeChannel.removeChannelIfDisconnected; }}
1 private final Random random = new Random();
2
3 protected <T> Invoker<T> doSelect(List<Invoker<T>> invokers, URL url, Invocation invocation) {
4 int length = invokers.size(); // 总个数
5 ...//权重计算
6 // 如果权重相同或权重为0则均等随机
7 return invokers.get(random.nextInt(length));
8 }
public void received(Channel channel, Object message) throws RemotingException { channel.setAttribute(KEY_READ_TIMESTAMP, System.currentTimeMillis; ExchangeChannel exchangeChannel = HeaderExchangeChannel.getOrAddChannel; try { //request类型的消息 if (message instanceof Request) { Request request = message; if (request.isEvent {//判断心跳还是正常请求 // 处理心跳 handlerEvent(channel, request); } else {//正常的请求 //需要返回 if (request.isTwoWay { //处理请求，并构造响应信息，这在上面已经解析过了 Response response = handleRequest(exchangeChannel, request); //NettyChannel，发送响应信息 channel.send; } else {//不需要返回的处理 handler.received(exchangeChannel, request.getData; } } } else if (message instanceof Response) {//response类型的消息 handleResponse(channel, message); } else if (message instanceof String) { if (isClientSide { Exception e = new Exception("Dubbo client can not supported string message: " + message + " in channel: " + channel + ", url: " + channel.getUrl; } else {//telnet类型 String echo = handler.telnet(channel, message); if (echo != null && echo.length { channel.send; } } } else { handler.received(exchangeChannel, message); } } finally { HeaderExchangeChannel.removeChannelIfDisconnected; }}
那里直接重临了。到此就早已选出能够被调用的RegistryDirectory$InvokerDelegete实例子集了。记下来先取得负载均衡器，暗中同意是RandomLoadBalance。最终执行FailoverClusterInvoker.
public void received(Channel channel, Object message) throws RemotingException { channel.setAttribute(KEY_READ_TIMESTAMP, System.currentTimeMillis; ExchangeChannel exchangeChannel = HeaderExchangeChannel.getOrAddChannel; try { //request类型的消息 if (message instanceof Request) { Request request = message; if (request.isEvent {//判断心跳还是正常请求 // 处理心跳 handlerEvent(channel, request); } else {//正常的请求 //需要返回 if (request.isTwoWay { //处理请求，并构造响应信息 Response response = handleRequest(exchangeChannel, request); //NettyChannel，发送响应信息 channel.send; } else {//不需要返回的处理 handler.received(exchangeChannel, request.getData; } } } else if (message instanceof Response) {//response类型的消息 handleResponse(channel, message); } else if (message instanceof String) { if (isClientSide { Exception e = new Exception("Dubbo client can not supported string message: " + message + " in channel: " + channel + ", url: " + channel.getUrl; } else {//telnet类型 String echo = handler.telnet(channel, message); if (echo != null && echo.length { channel.send; } } } else { handler.received(exchangeChannel, message); } } finally { HeaderExchangeChannel.removeChannelIfDisconnected; }}
1 private final Invoker<T> invoker;//ProtocolFilterWrapper$Invoker
2
3 public Result invoke(Invocation invocation) throws RpcException {
4 return invoker.invoke(invocation);
5 }
下一场在新线程，Channel伊夫ntRunnable的run方法中进入DecodeHandler：
尔后采用MockClusterInvoker.invoke(Invocation invocation)实行长途调用：
Response handleRequest(ExchangeChannel channel, Request req) throws RemotingException { Response res = new Response(req.getId(), req.getVersion; if (req.isBroken { Object data = req.getData(); String msg; if (data == null) msg = null; else if (data instanceof Throwable) msg = StringUtils.toString((Throwable) data); else msg = data.toString(); res.setErrorMessage("Fail to decode request due to: " + msg); res.setStatus(Response.BAD_REQUEST); return res; } // find handler by message class. Object msg = req.getData(); try { //处理请求数据，handler是DubboProtocol中的new的一个ExchangeHandlerAdapter Object result = handler.reply(channel, msg); res.setStatus(Response.OK); res.setResult; } catch (Throwable e) { } return res;}
这里的handler就是InvokerInvocationHandler
public void send(Object message, boolean sent) throws RemotingException { //AbstractChannel的处理 super.send(message, sent); boolean success = true; int timeout = 0; try { ChannelFuture future = channel.write; if { timeout = getUrl().getPositiveParameter(Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT); success = future.await; } Throwable cause = future.getCause(); if (cause != null) { throw cause; } } catch (Throwable e) { throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress() + ", cause: " + e.getMessage; } if(! success) { throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress() + "in timeout(" + timeout + "ms) limit"); }}
ListenerInvokerWrapper.invoke
消费者还足以通过安装async、sent、return来调动处理逻辑，async指异步依然二只请求，sent指是还是不是等待请求新闻爆发即阻塞等待是不是中标发出请求、return指是还是不是忽略重返值即但方向通讯，一般异步时行使以减小Future对象的创办和管理资金财产。
1 private final ExchangeChannel channel;//HeaderExchangeChannel
2
3 public ResponseFuture request(Object request, int timeout) throws RemotingException {
4 return channel.request(request, timeout);
5 }
新闻处理完后回来到HeaderExchangeHandler的received方法：
1 public <T> List<Invoker<T>> route(final List<Invoker<T>> invokers,
2 URL url, final Invocation invocation) throws RpcException {
3 if (invocation.getAttachments() == null) {
4 return getNormalInvokers(invokers);
5 } else {
6 String value = invocation.getAttachments().get(Constants.INVOCATION_NEED_MOCK);
7 if (value == null)
8 return getNormalInvokers(invokers);
9 else if (Boolean.TRUE.toString().equalsIgnoreCase(value)) {
10 return getMockedInvokers(invokers);
11 }
12 }
13 return invokers;
14 }
15
16 private <T> List<Invoker<T>> getNormalInvokers(final List<Invoker<T>> invokers) {
17 if (!hasMockProviders(invokers)) {
18 return invokers;
19 } else {
20 List<Invoker<T>> sInvokers = new ArrayList<Invoker<T>>(invokers.size());
21 for (Invoker<T> invoker : invokers) {
22 if (!invoker.getUrl().getProtocol().equals(Constants.MOCK_PROTOCOL)) {
23 sInvokers.add(invoker);
24 }
25 }
26 return sInvokers;
27 }
28 }
public Result invoke(Invocation invocation) throws RpcException { Result result = null; //获取mock属性的值，我们没有配置，默认false String value = directory.getUrl().getMethodParameter(invocation.getMethodName(), Constants.MOCK_KEY, Boolean.FALSE.toString; if (value.length() == 0 || value.equalsIgnoreCase{ //这里invoker是FailoverClusterInvoker result = this.invoker.invoke(invocation); } else if (value.startsWith { //force:direct mock result = doMockInvoke(invocation, null); } else { //fail-mock try { result = this.invoker.invoke(invocation); }catch (RpcException e) { if ) { throw e; } else { result = doMockInvoke(invocation, e); } } } return result;}
以往就会实行一多级的filter，那些filter后续会讲，现在径直实施到DubboInvoker.invoke，实际上该办法在其父类AbstractInvoker中，AbstractInvoker又调用了DubboInvoker.doInvoke：
result =
this.invoker.invoke(invocation);那里invoker是FailoverClusterInvoker，会首先进入AbstractClusterInvoker的invoke方法：
1 private final org.jboss.netty.channel.Channel channel;//NioClientSocketChannel
2
3 public void send(Object message, boolean sent) throws RemotingException {
4 super.send(message, sent);
5
6 boolean success = true;
7 int timeout = 0;
8 try {
9 ChannelFuture future = channel.write(message);
10 if (sent) {
11 timeout = getUrl().getPositiveParameter(Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT);
12 success = future.await(timeout);
13 }
14 Throwable cause = future.getCause();
15 if (cause != null) {
16 throw cause;
17 }
18 } catch (Throwable e) {
19 throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress() + ", cause: " + e.getMessage(), e);
20 }
21
22 if (!success) {
23 throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress()
24 + "in timeout(" + timeout + "ms) limit");
25 }
26 }
先看下getInvoker获取Invoker：
那里依据办法名sayHello取出五个RegistryDirectory$InvokerDelegete实例。最后通过Router实行过滤，那里唯有3个Router，便是MockInvokersSelector。
public Result invoke(Invocation invocation) throws RpcException { return invoker.invoke(invocation);}
Map<String, List<Invoker<T>>> methodInvokerMap={
sayHello=[provider1的RegistryDirectory$InvokerDelegete实例, provider2的RegistryDirectory$InvokerDelegete实例], *=[provider1的RegistryDirectory$InvokerDelegete实例, provider2的RegistryDirectory$InvokerDelegete实例]}
解码之后到HeaderExchangeHandler的received方法：
1 private ExchangeClient client;//HeaderExchangeClient
2
3 public ResponseFuture request(Object request, int timeout) throws RemotingException {
4 return client.request(request, timeout);
5 }
进入AllChannelHandler：
1 private final Channel channel;//NettyClient
2
3 public ResponseFuture request(Object request, int timeout) throws RemotingException {
4 if (closed) {
5 throw new RemotingException(this.getLocalAddress(), null, "Failed to send request " + request + ", cause: The channel " + this + " is closed!");
6 }
7 // create request.
8 Request req = new Request();
9 req.setVersion("2.0.0");
10 req.setTwoWay(true);
11 req.setData(request);
12 DefaultFuture future = new DefaultFuture(channel, req, timeout);
13 try {
14 channel.send(req);
15 } catch (RemotingException e) {
16 future.cancel();
17 throw e;
18 }
19 return future;
20 }
private void decode(Object message) { if (message != null && message instanceof Decodeable) { try { ((Decodeable)message).decode(); } catch (Throwable e) {。。。} // ~ end of catch } // ~ end of if}
上边的channel是NettyClient实例，那里的send实际上是调用其父类AbstractClient的父类AbstractPeer，AbstractPeer调用AbstractClient.send：
大家那边运用的是手拉手调用，看 currentClient.request(inv,
timeout).get();方法，这里的client是ReferenceCountExchangeClient，直接调用HeaderExchangeClient的request方法：
NettyChannel.send
public void received(Channel channel, Object message) throws RemotingException { //不清楚啥意思 if (message instanceof Decodeable) { decode; } //解码请求类型 if (message instanceof Request) { decode(message).getData; } //解码响应类型 if (message instanceof Response) { decode( (message).getResult; } //解码之后到HeaderExchangeHandler中处理 handler.received(channel, message);}
1 private final Invoker<T> invoker;//ListenerInvokerWrapper
2
3 public Result invoke(Invocation invocation) throws RpcException {
4 return invoker.invoke(invocation);
5 }
public Result invoke(Invocation invocation) throws RpcException { try { //先doInvoke //然后封装成结果返回 return new RpcResult(doInvoke(proxy, invocation.getMethodName(), invocation.getParameterTypes(), invocation.getArguments; } catch (InvocationTargetException e) {。。。}}
HeaderExchangeClient.request
public void received(Channel channel, Object message) throws RemotingException { ExecutorService cexecutor = getExecutorService(); try { cexecutor.execute(new ChannelEventRunnable(channel, handler, ChannelState.RECEIVED, message)); } catch (Throwable t) { throw new ExecutionException(message, channel, getClass() + " error when process received event .", t); }}
public void received(Channel channel, Object message) throws RemotingException { setReadTimestamp; //心跳请求处理 if (isHeartbeatRequest { Request req = message; if (req.isTwoWay { Response res = new Response(req.getId(), req.getVersion; res.setEvent(Response.HEARTBEAT_EVENT); channel.send; } return; } //心跳回应消息处理 if (isHeartbeatResponse { return; } //这里是AllChannelHandler handler.received(channel, message);}
public <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) { // TODO Wrapper类不能正确处理带$的类名 final Wrapper wrapper = Wrapper.getWrapper(proxy.getClass().getName().indexOf < 0 ? proxy.getClass; return new AbstractProxyInvoker<T>(proxy, type, url) { @Override protected Object doInvoke(T proxy, String methodName, Class<?>[] parameterTypes, Object[] arguments) throws Throwable { //这里就调用了具体的方法 return wrapper.invokeMethod(proxy, methodName, parameterTypes, arguments); } };}
随后进入AbstractProxyInvoker：
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception { //获取channel NettyChannel channel = NettyChannel.getOrAddChannel(ctx.getChannel(), url, handler); try { //这里handler是NettyServer handler.received(channel, e.getMessage; } finally { NettyChannel.removeChannelIfDisconnected(ctx.getChannel; }}
进入HeaderExchangeChannel的request方法：
跟着会跻身AbstractPeer的received方法：
这里的doInvoke是在JavassistProxyFactory中的AbstractProxyInvoker实例：
//proxy是代理的真实对象//method调用真实对象的方法//args调用真实对象的方法的参数public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { //方法名sayHello String methodName = method.getName(); //参数类型 Class<?>[] parameterTypes = method.getParameterTypes(); if (method.getDeclaringClass() == Object.class) { return method.invoke(invoker, args); } if ("toString".equals(methodName) && parameterTypes.length == 0) { return invoker.toString(); } if ("hashCode".equals(methodName) && parameterTypes.length == 0) { return invoker.hashCode(); } if ("equals".equals(methodName) && parameterTypes.length == 1) { return invoker.equals; } //invoker是MockClusterInvoker //首先new RpcInvocation //然后invoker.invoke //最后recreate //返回结果 return invoker.invoke(new RpcInvocation(method, args)).recreate();}
服务端已经打起头口并监听请求的过来，当服务消费者发送调用请求的时候，经过Netty的处理后会到dubbo中的codec相关办法中先实行解码，入口是NettyCodecAdapter.messageReceived()：
Java动态代理，每四个动态代理类都必须要兑现InvocationHandler那一个接口，并且每3个代理类的实例都关涉到了叁个handler，当大家透过代办对象调用二个办法的时候，那一个点子就会被转载为由达成了InvocationHandler那么些接口的类的invoke方法来进展调用。
AbstractClient执行发送：
进入DubboProtocol中的ExchangeHandlerAdapter的replay方法：
channel.send(message,
sent);首先通过AbstractChannel的send方法处理，只是一口咬住不放是还是不是关闭了，然后是NettyChannel的send来持续处理，那里就把音讯发送到服务端了：
FailoverClusterInvoker.doInvoke()：
再看执行调用invoker.invoke;，会先进入InvokerWrapper：
进入HeartbeatHandler的received方法：
static void handleResponse(Channel channel, Response response) throws RemotingException { if (response != null && !response.isHeartbeat { DefaultFuture.received(channel, response); }}
public void received(Channel channel, Object message) throws RemotingException { setReadTimestamp; if (isHeartbeatRequest { Request req = message; if (req.isTwoWay { Response res = new Response(req.getId(), req.getVersion; res.setEvent(Response.HEARTBEAT_EVENT); channel.send; if (logger.isInfoEnabled { int heartbeat = channel.getUrl().getParameter(Constants.HEARTBEAT_KEY, 0); if(logger.isDebugEnabled { logger.debug("Received heartbeat from remote channel " + channel.getRemoteAddress() + ", cause: The channel has no data-transmission exceeds a heartbeat period" + (heartbeat > 0 ? ": " + heartbeat + "ms" : "")); } } } return; } if (isHeartbeatResponse { if (logger.isDebugEnabled { logger.debug( new StringBuilder .append("Receive heartbeat response in thread ") .append(Thread.currentThread().getName .toString; } return; } //AllChannelHandler handler.received(channel, message);}
public void received(Channel channel, Object message) throws RemotingException { //是多消息的话，使用多消息处理器处理 if (message instanceof MultiMessage) { MultiMessage list = (MultiMessage)message; for(Object obj : list) { handler.received(channel, obj); } } else { //这里是HeartbeatHandler handler.received(channel, message); }}
InvokerInvocationHandler完成了InvocationHandler接口，当大家调用helloService.sayHello();的时候，实际上会调用invoke()方法：
protected Result doInvoke(final Invocation invocation) throws Throwable { RpcInvocation inv = (RpcInvocation) invocation; final String methodName = RpcUtils.getMethodName(invocation); inv.setAttachment(Constants.PATH_KEY, getUrl().getPath; inv.setAttachment(Constants.VERSION_KEY, version); ExchangeClient currentClient; //在初始化的时候，引用服务的过程中会保存一个连接到服务端的Client if (clients.length == 1) { currentClient = clients[0]; } else { currentClient = clients[index.getAndIncrement() % clients.length]; } try { //异步标志 boolean isAsync = RpcUtils.isAsync, invocation); //单向标志 boolean isOneway = RpcUtils.isOneway, invocation); int timeout = getUrl().getMethodParameter(methodName, Constants.TIMEOUT_KEY,Constants.DEFAULT_TIMEOUT); //单向的，反送完不管结果 if { boolean isSent = getUrl().getMethodParameter(methodName, Constants.SENT_KEY, false); currentClient.send(inv, isSent); RpcContext.getContext().setFuture; return new RpcResult(); } else if {//异步的，发送完需要得到Future ResponseFuture future = currentClient.request(inv, timeout) ; RpcContext.getContext().setFuture(new FutureAdapter<Object>; return new RpcResult(); } else {//同步调用，我们这里使用的这种方式 RpcContext.getContext().setFuture; //HeaderExchangeClient return currentClient.request(inv, timeout).get(); } } catch (TimeoutException e) {。。。}}
服务消费者通过开始化之后，得到的是3个动态代理类，InvokerInvocationHandler，包罗MockClusterInvoker，MockClusterInvoker包罗多个RegistryDirectory和FailoverClusterInvoker。
channel.send，首先会调用AbstractPeer的send方法：
public void send(Object message, boolean sent) throws RemotingException { super.send(message, sent); boolean success = true; int timeout = 0; try { //交给netty处理 ChannelFuture future = channel.write; if { timeout = getUrl().getPositiveParameter(Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT); success = future.await; } Throwable cause = future.getCause(); if (cause != null) { throw cause; } } catch (Throwable e) { throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress() + ", cause: " + e.getMessage; } if(! success) { throw new RemotingException(this, "Failed to send message " + message + " to " + getRemoteAddress() + "in timeout(" + timeout + "ms) limit"); }}
进去HeartbeatHandler，根据不一样品类举办处理：
劳务提供者开始化完毕现在，对外暴光Exporter。服务消费者开首化完毕之后，获得的是Proxy代理，方法调用的时候就算调用代理。