Dubbo源码解析（二）-以zookeeper为注册中心，深入了解服务调用方消费者注册以及调用
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了Dubbo源码解析（二）-以zookeeper为注册中心，深入了解服务调用方消费者注册以及调用，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含21743字，纯文字阅读大概需要32分钟。
内容图文
上篇讲了服务提供方暴露出对应的接口后，以及在zookeeper中创建了provider节点，https://blog.csdn.net/qq_38340127/article/details/112698774接下来继续服务调用方调试。
xml配置
<?xml version="1.0" encoding="UTF-8"?>
<!--
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contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">
<dubbo:application name="demo-consumer"/>
<dubbo:registry address="zookeeper://127.0.0.1:2181" />
<!-- generate proxy for the remote service, then demoService can be used in the same way as the
local regular interface -->
<dubbo:reference id="demoService" check="false" interface="org.apache.dubbo.demo.DemoService"/>
</beans>
reference对应
registerBeanDefinitionParser("reference", new DubboBeanDefinitionParser(ReferenceBean.class, false));通过对ReferenceBean（implements FactoryBean说明为一个生成bean的对象，那么具体get就是通过该对象的getObject方法）进行调试查看
org.apache.dubbo.config.spring.ReferenceBean#getObject
@Override
public Object getObject() {
return get();
}
通过get方法得到对应的ref
public synchronized T get() {
checkAndUpdateSubConfigs();
if (destroyed) {
throw new IllegalStateException("The invoker of ReferenceConfig(" + url + ") has already destroyed!");
}
if (ref == null) {
init();
}
return ref;
}
可以看出主要操作为init()
对init进行解析可以看出先是一系列的判断和生成对应的map
然后根据map代理生成ref
ref = createProxy(map);本次案例生成的map为：分别对应方法和接口等信息
// 判断是否为本地调用，若为本地调用
if (shouldJvmRefer(map)) {
URL url = new URL(LOCAL_PROTOCOL, LOCALHOST_VALUE, 0, interfaceClass.getName()).addParameters(map);
invoker = REF_PROTOCOL.refer(interfaceClass, url);
if (logger.isInfoEnabled()) {
logger.info("Using injvm service " + interfaceClass.getName());
}
}
// 可能又多个注册中心，如果只有一个则直接进行refer 本次案例中只有1个所以直接走第一个
if (urls.size() == 1) {
invoker = REF_PROTOCOL.refer(interfaceClass, urls.get(0));
} else {
List<Invoker<?>> invokers = new ArrayList<Invoker<?>>();
URL registryURL = null;
for (URL url : urls) {
invokers.add(REF_PROTOCOL.refer(interfaceClass, url));
if (REGISTRY_PROTOCOL.equals(url.getProtocol())) {
registryURL = url; // use last registry url
}
}
if (registryURL != null) { // registry url is available
// use RegistryAwareCluster only when register's CLUSTER is available
URL u = registryURL.addParameter(CLUSTER_KEY, RegistryAwareCluster.NAME);
// The invoker wrap relation would be: RegistryAwareClusterInvoker(StaticDirectory) -> FailoverClusterInvoker(RegistryDirectory, will execute route) -> Invoker
invoker = CLUSTER.join(new StaticDirectory(u, invokers));
} else { // not a registry url, must be direct invoke.
invoker = CLUSTER.join(new StaticDirectory(invokers));
}
}深入refer方法可以得到：
private <T> Invoker<T> doRefer(Cluster cluster, Registry registry, Class<T> type, URL url) {
RegistryDirectory<T> directory = new RegistryDirectory<T>(type, url);
directory.setRegistry(registry);
directory.setProtocol(protocol);
// all attributes of REFER_KEY
Map<String, String> parameters = new HashMap<String, String>(directory.getUrl().getParameters());
URL subscribeUrl = new URL(CONSUMER_PROTOCOL, parameters.remove(REGISTER_IP_KEY), 0, type.getName(), parameters);
if (!ANY_VALUE.equals(url.getServiceInterface()) && url.getParameter(REGISTER_KEY, true)) {
directory.setRegisteredConsumerUrl(getRegisteredConsumerUrl(subscribeUrl, url));
registry.register(directory.getRegisteredConsumerUrl());
}
directory.buildRouterChain(subscribeUrl);
// 通过订阅的模式
directory.subscribe(subscribeUrl.addParameter(CATEGORY_KEY,
PROVIDERS_CATEGORY + "," + CONFIGURATORS_CATEGORY + "," + ROUTERS_CATEGORY));
Invoker invoker = cluster.join(directory);
ProviderConsumerRegTable.registerConsumer(invoker, url, subscribeUrl, directory);
return invoker;
}因为是zookeeper注册中心所以先是创建了在consumer上的临时节点，然后调用了订阅对应的节点
org.apache.dubbo.registry.zookeeper.ZookeeperRegistry#doSubscribe List<URL> urls = new ArrayList<>();
for (String path : toCategoriesPath(url)) { //当时消费之进行订阅时，一共监听了对应的providers、configurators、routers
ConcurrentMap<NotifyListener, ChildListener> listeners = zkListeners.get(url);
if (listeners == null) {
zkListeners.putIfAbsent(url, new ConcurrentHashMap<>());
listeners = zkListeners.get(url);
}
ChildListener zkListener = listeners.get(listener);
if (zkListener == null) {
listeners.putIfAbsent(listener, (parentPath, currentChilds) -> ZookeeperRegistry.this.notify(url, listener, toUrlsWithEmpty(url, parentPath, currentChilds)));
zkListener = listeners.get(listener);
}
zkClient.create(path, false);
List<String> children = zkClient.addChildListener(path, zkListener);
if (children != null) {
urls.addAll(toUrlsWithEmpty(url, path, children));
}
}
notify(url, listener, urls);然后调用norify方法：一直调试发现
protected void notify(URL url, NotifyListener listener, List<URL> urls) {
if (url == null) {
throw new IllegalArgumentException("notify url == null");
}
if (listener == null) {
throw new IllegalArgumentException("notify listener == null");
}
if ((CollectionUtils.isEmpty(urls))
&& !ANY_VALUE.equals(url.getServiceInterface())) {
logger.warn("Ignore empty notify urls for subscribe url " + url);
return;
}
if (logger.isInfoEnabled()) {
logger.info("Notify urls for subscribe url " + url + ", urls: " + urls);
}
// keep every provider's category.
Map<String, List<URL>> result = new HashMap<>();
for (URL u : urls) {
if (UrlUtils.isMatch(url, u)) {
String category = u.getParameter(CATEGORY_KEY, DEFAULT_CATEGORY);
List<URL> categoryList = result.computeIfAbsent(category, k -> new ArrayList<>());
categoryList.add(u);
}
}
if (result.size() == 0) {
return;
}
Map<String, List<URL>> categoryNotified = notified.computeIfAbsent(url, u -> new ConcurrentHashMap<>());
for (Map.Entry<String, List<URL>> entry : result.entrySet()) {
String category = entry.getKey();
List<URL> categoryList = entry.getValue();
categoryNotified.put(category, categoryList);
listener.notify(categoryList);
// We will update our cache file after each notification.
// When our Registry has a subscribe failure due to network jitter, we can return at least the existing cache URL.
saveProperties(url);
}
}进行不断调试发现上列代码中的主要节点为：
listener.notify(categoryList); @Override
public synchronized void notify(List<URL> urls) {
Map<String, List<URL>> categoryUrls = urls.stream()
.filter(Objects::nonNull)
.filter(this::isValidCategory)
.filter(this::isNotCompatibleFor26x)
.collect(Collectors.groupingBy(url -> {
if (UrlUtils.isConfigurator(url)) {
return CONFIGURATORS_CATEGORY;
} else if (UrlUtils.isRoute(url)) {
return ROUTERS_CATEGORY;
} else if (UrlUtils.isProvider(url)) {
return PROVIDERS_CATEGORY;
}
return "";
}));
List<URL> configuratorURLs = categoryUrls.getOrDefault(CONFIGURATORS_CATEGORY, Collections.emptyList());
this.configurators = Configurator.toConfigurators(configuratorURLs).orElse(this.configurators);
List<URL> routerURLs = categoryUrls.getOrDefault(ROUTERS_CATEGORY, Collections.emptyList());
toRouters(routerURLs).ifPresent(this::addRouters);
// providers
List<URL> providerURLs = categoryUrls.getOrDefault(PROVIDERS_CATEGORY, Collections.emptyList());
refreshOverrideAndInvoker(providerURLs);
}当为provider时providerURLs对象如下：
再跟进
private void refreshOverrideAndInvoker(List<URL> urls) {
// mock zookeeper://xxx?mock=return null
overrideDirectoryUrl(); // 主要进行一些override操作
refreshInvoker(urls);//具体操作
}继续跟进，可以看出代码refreshInvoker会先进行一系列判断然后主要通过方法
Map<String, Invoker<T>> newUrlInvokerMap = toInvokers(invokerUrls);// Translate url list to Invoker map
主要方法如下：
invoker = new InvokerDelegate<>(protocol.refer(serviceType, url), url, providerUrl);
中的主要方法protocol.refer(serviceType, url)
一步步操作后会跟进到
@Override
public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException {
return new AsyncToSyncInvoker<>(protocolBindingRefer(type, url));
}
再跟进到
org.apache.dubbo.rpc.protocol.dubbo.DubboProtocol#protocolBindingRefer方法
@Override
public <T> Invoker<T> protocolBindingRefer(Class<T> serviceType, URL url) throws RpcException {
optimizeSerialization(url);
// create rpc invoker. 此处为对应的Invoker
DubboInvoker<T> invoker = new DubboInvoker<T>(serviceType, url, getClients(url), invokers);
invokers.add(invoker);
return invoker;
}然后可以看出是通过创建client
private ExchangeClient[] getClients(URL url) {
// whether to share connection
boolean useShareConnect = false;
int connections = url.getParameter(CONNECTIONS_KEY, 0);
List<ReferenceCountExchangeClient> shareClients = null;
// if not configured, connection is shared, otherwise, one connection for one service
if (connections == 0) {
useShareConnect = true;
/**
* The xml configuration should have a higher priority than properties.
*/
String shareConnectionsStr = url.getParameter(SHARE_CONNECTIONS_KEY, (String) null);
connections = Integer.parseInt(StringUtils.isBlank(shareConnectionsStr) ? ConfigUtils.getProperty(SHARE_CONNECTIONS_KEY,
DEFAULT_SHARE_CONNECTIONS) : shareConnectionsStr);
shareClients = getSharedClient(url, connections); // 获取到对应的clients
}
ExchangeClient[] clients = new ExchangeClient[connections];
for (int i = 0; i < clients.length; i++) {
if (useShareConnect) {
clients[i] = shareClients.get(i);
} else {
clients[i] = initClient(url);
}
}
return clients;
} private List<ReferenceCountExchangeClient> getSharedClient(URL url, int connectNum) {
String key = url.getAddress();
List<ReferenceCountExchangeClient> clients = referenceClientMap.get(key);
if (checkClientCanUse(clients)) {
batchClientRefIncr(clients);
return clients;
}
// 通过加锁判断是否获取到对应的client
locks.putIfAbsent(key, new Object());
synchronized (locks.get(key)) {
clients = referenceClientMap.get(key);
// dubbo check
if (checkClientCanUse(clients)) {
batchClientRefIncr(clients);
return clients;
}
// connectNum must be greater than or equal to 1
connectNum = Math.max(connectNum, 1);
// If the clients is empty, then the first initialization is
if (CollectionUtils.isEmpty(clients)) {
// 核心方法生成客户端clents
clients = buildReferenceCountExchangeClientList(url, connectNum);
referenceClientMap.put(key, clients);
} else {
for (int i = 0; i < clients.size(); i++) {
ReferenceCountExchangeClient referenceCountExchangeClient = clients.get(i);
// If there is a client in the list that is no longer available, create a new one to replace him.
if (referenceCountExchangeClient == null || referenceCountExchangeClient.isClosed()) {
clients.set(i, buildReferenceCountExchangeClient(url));
continue;
}
referenceCountExchangeClient.incrementAndGetCount();
}
}
/**
* I understand that the purpose of the remove operation here is to avoid the expired url key
* always occupying this memory space.
*/
locks.remove(key);
return clients;
}
}具体实现为
clients = buildReferenceCountExchangeClientList(url, connectNum);继续跟进根据连接数生成对应的client
private ReferenceCountExchangeClient buildReferenceCountExchangeClient(URL url) {
ExchangeClient exchangeClient = initClient(url);
return new ReferenceCountExchangeClient(exchangeClient);
} private ExchangeClient initClient(URL url) {
// client type setting.
String str = url.getParameter(CLIENT_KEY, url.getParameter(SERVER_KEY, DEFAULT_REMOTING_CLIENT));
url = url.addParameter(CODEC_KEY, DubboCodec.NAME);
// enable heartbeat by default
url = url.addParameterIfAbsent(HEARTBEAT_KEY, String.valueOf(DEFAULT_HEARTBEAT));
// BIO is not allowed since it has severe performance issue.
if (str != null && str.length() > 0 && !ExtensionLoader.getExtensionLoader(Transporter.class).hasExtension(str)) {
throw new RpcException("Unsupported client type: " + str + "," +
" supported client type is " + StringUtils.join(ExtensionLoader.getExtensionLoader(Transporter.class).getSupportedExtensions(), " "));
}
ExchangeClient client;
try {
// connection should be lazy
if (url.getParameter(LAZY_CONNECT_KEY, false)) {
client = new LazyConnectExchangeClient(url, requestHandler);
} else {
client = Exchangers.connect(url, requestHandler);
}
} catch (RemotingException e) {
throw new RpcException("Fail to create remoting client for service(" + url + "): " + e.getMessage(), e);
}
return client;
}可以看出为通过Exchangers进行连接
public static ExchangeClient connect(URL url, ExchangeHandler handler) throws RemotingException {
if (url == null) {
throw new IllegalArgumentException("url == null");
}
if (handler == null) {
throw new IllegalArgumentException("handler == null");
}
url = url.addParameterIfAbsent(Constants.CODEC_KEY, "exchange");
return getExchanger(url).connect(url, handler);
}
//发现为通过HeaderExchanger进行connect即
@Override
public ExchangeClient connect(URL url, ExchangeHandler handler) throws RemotingException {
return new HeaderExchangeClient(Transporters.connect(url, new DecodeHandler(new HeaderExchangeHandler(handler))), true);
}
// 继续跟进
public static Client connect(URL url, ChannelHandler... handlers) throws RemotingException {
if (url == null) {
throw new IllegalArgumentException("url == null");
}
ChannelHandler handler;
if (handlers == null || handlers.length == 0) {
handler = new ChannelHandlerAdapter();
} else if (handlers.length == 1) {
handler = handlers[0];
} else {
handler = new ChannelHandlerDispatcher(handlers);
}
return getTransporter().connect(url, handler);
}
//dubbo协议为调用nettyTransporter
@Override
public Client connect(URL url, ChannelHandler listener) throws RemotingException {
return new NettyClient(url, listener);
}
// 然后调用
public AbstractClient(URL url, ChannelHandler handler) throws RemotingException {
super(url, handler);
needReconnect = url.getParameter(Constants.SEND_RECONNECT_KEY, false);
try {
doOpen();
} catch (Throwable t) {
close();
throw new RemotingException(url.toInetSocketAddress(), null,
"Failed to start " + getClass().getSimpleName() + " " + NetUtils.getLocalAddress()
+ " connect to the server " + getRemoteAddress() + ", cause: " + t.getMessage(), t);
}
try {
// connect.
connect();
if (logger.isInfoEnabled()) {
logger.info("Start " + getClass().getSimpleName() + " " + NetUtils.getLocalAddress() + " connect to the server " + getRemoteAddress());
}
} catch (RemotingException t) {
if (url.getParameter(Constants.CHECK_KEY, true)) {
close();
throw t;
} else {
logger.warn("Failed to start " + getClass().getSimpleName() + " " + NetUtils.getLocalAddress()
+ " connect to the server " + getRemoteAddress() + " (check == false, ignore and retry later!), cause: " + t.getMessage(), t);
}
} catch (Throwable t) {
close();
throw new RemotingException(url.toInetSocketAddress(), null,
"Failed to start " + getClass().getSimpleName() + " " + NetUtils.getLocalAddress()
+ " connect to the server " + getRemoteAddress() + ", cause: " + t.getMessage(), t);
}
executor = (ExecutorService) ExtensionLoader.getExtensionLoader(DataStore.class)
.getDefaultExtension().get(CONSUMER_SIDE, Integer.toString(url.getPort()));
ExtensionLoader.getExtensionLoader(DataStore.class)
.getDefaultExtension().remove(CONSUMER_SIDE, Integer.toString(url.getPort()));
}
具体通过doOpen进行client和server的连接
@Override
protected void doOpen() throws Throwable {
final NettyClientHandler nettyClientHandler = new NettyClientHandler(getUrl(), this);
bootstrap = new Bootstrap();
bootstrap.group(nioEventLoopGroup)
.option(ChannelOption.SO_KEEPALIVE, true)
.option(ChannelOption.TCP_NODELAY, true)
.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT)
//.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, getTimeout())
.channel(NioSocketChannel.class);
if (getConnectTimeout() < 3000) {
bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 3000);
} else {
bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, getConnectTimeout());
}
bootstrap.handler(new ChannelInitializer() {
@Override
protected void initChannel(Channel ch) throws Exception {
int heartbeatInterval = UrlUtils.getHeartbeat(getUrl());
NettyCodecAdapter adapter = new NettyCodecAdapter(getCodec(), getUrl(), NettyClient.this);
ch.pipeline()//.addLast("logging",new LoggingHandler(LogLevel.INFO))//for debug
.addLast("decoder", adapter.getDecoder())
.addLast("encoder", adapter.getEncoder())
.addLast("client-idle-handler", new IdleStateHandler(heartbeatInterval, 0, 0, MILLISECONDS))
.addLast("handler", nettyClientHandler);
String socksProxyHost = ConfigUtils.getProperty(SOCKS_PROXY_HOST);
if(socksProxyHost != null) {
int socksProxyPort = Integer.parseInt(ConfigUtils.getProperty(SOCKS_PROXY_PORT, DEFAULT_SOCKS_PROXY_PORT));
Socks5ProxyHandler socks5ProxyHandler = new Socks5ProxyHandler(new InetSocketAddress(socksProxyHost, socksProxyPort));
ch.pipeline().addFirst(socks5ProxyHandler);
}
}
});
}然后进行connect操作
@Override
protected void doConnect() throws Throwable {
long start = System.currentTimeMillis();
ChannelFuture future = bootstrap.connect(getConnectAddress());
try {
boolean ret = future.awaitUninterruptibly(getConnectTimeout(), MILLISECONDS);
if (ret && future.isSuccess()) {
Channel newChannel = future.channel();
try {
// Close old channel
// copy reference
Channel oldChannel = NettyClient.this.channel;
if (oldChannel != null) {
try {
if (logger.isInfoEnabled()) {
logger.info("Close old netty channel " + oldChannel + " on create new netty channel " + newChannel);
}
oldChannel.close();
} finally {
NettyChannel.removeChannelIfDisconnected(oldChannel);
}
}
} finally {
if (NettyClient.this.isClosed()) {
try {
if (logger.isInfoEnabled()) {
logger.info("Close new netty channel " + newChannel + ", because the client closed.");
}
newChannel.close();
} finally {
NettyClient.this.channel = null;
NettyChannel.removeChannelIfDisconnected(newChannel);
}
} else {
NettyClient.this.channel = newChannel;
}
}
} else if (future.cause() != null) {
throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server "
+ getRemoteAddress() + ", error message is:" + future.cause().getMessage(), future.cause());
} else {
throw new RemotingException(this, "client(url: " + getUrl() + ") failed to connect to server "
+ getRemoteAddress() + " client-side timeout "
+ getConnectTimeout() + "ms (elapsed: " + (System.currentTimeMillis() - start) + "ms) from netty client "
+ NetUtils.getLocalHost() + " using dubbo version " + Version.getVersion());
}
} finally {
// just add new valid channel to NettyChannel's cache
if (!isConnected()) {
//future.cancel(true);
}
}
}连接等完成后返回对应的
DubboInvoker并进行层层封装最终得到一个代理的Ref对象。获取到对象后执行对应的方法则最终调用的为org.apache.dubbo.rpc.protocol.dubbo.DubboInvoker#doInvoke：
@Override
protected Result doInvoke(final Invocation invocation) throws Throwable {
RpcInvocation inv = (RpcInvocation) invocation;
final String methodName = RpcUtils.getMethodName(invocation);
inv.setAttachment(PATH_KEY, getUrl().getPath());
inv.setAttachment(VERSION_KEY, version);
ExchangeClient currentClient;
if (clients.length == 1) {
currentClient = clients[0];
} else {
currentClient = clients[index.getAndIncrement() % clients.length];
}
try {
boolean isOneway = RpcUtils.isOneway(getUrl(), invocation);
int timeout = getUrl().getMethodParameter(methodName, TIMEOUT_KEY, DEFAULT_TIMEOUT);
if (isOneway) {
boolean isSent = getUrl().getMethodParameter(methodName, Constants.SENT_KEY, false);
currentClient.send(inv, isSent);
RpcContext.getContext().setFuture(null);
return AsyncRpcResult.newDefaultAsyncResult(invocation);
} else {
AsyncRpcResult asyncRpcResult = new AsyncRpcResult(inv);
CompletableFuture<Object> responseFuture = currentClient.request(inv, timeout);
asyncRpcResult.subscribeTo(responseFuture);
RpcContext.getContext().setFuture(new FutureAdapter(asyncRpcResult));
return asyncRpcResult;
}
} catch (TimeoutException e) {
throw new RpcException(RpcException.TIMEOUT_EXCEPTION, "Invoke remote method timeout. method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e);
} catch (RemotingException e) {
throw new RpcException(RpcException.NETWORK_EXCEPTION, "Failed to invoke remote method: " + invocation.getMethodName() + ", provider: " + getUrl() + ", cause: " + e.getMessage(), e);
}
}主要就是通过
CompletableFuture<Object> responseFuture = currentClient.request(inv, timeout);进行将数据进行传输对应的inv即
得到对应的结果
这里有个细节就是获取到的结果为对应的异步返回结果
CompletableFuture<Object> responseFuture = currentClient.request(inv, timeout);
asyncRpcResult.subscribeTo(responseFuture);
RpcContext.getContext().setFuture(new FutureAdapter(asyncRpcResult));
其中subscribeTo
public void subscribeTo(CompletableFuture<?> future) {
future.whenComplete((obj, t) -> {
if (t != null) {
this.completeExceptionally(t);
} else {
this.complete((Result) obj);
}
});
}使用Future获得异步执行结果时，要么调用阻塞方法get()，要么轮询看isDone()是否为true，这两种方法都不是很好，因为主线程也会被迫等待。
从Java 8开始引入了CompletableFuture，它针对Future做了改进，可以传入回调对象，当异步任务完成或者发生异常时，自动调用回调对象的回调方法。
所以得到了具体的结果。
总结
可以的出结论，再消费者进行获取到实例的时候进行了通过注册中心获取到对应的服务提供者列表，进行与服务端进行长连接，当调用方法时，通过对应的请求对象等让服务端收到请求，然后再执行对应的方法，将结果再返回给调用方，调用方异步等待结果返回。
后续：
负载均衡、对象序列化传输、心跳检测等具体待续
内容总结
以上是互联网集市为您收集整理的Dubbo源码解析（二）-以zookeeper为注册中心，深入了解服务调用方消费者注册以及调用全部内容，希望文章能够帮你解决Dubbo源码解析（二）-以zookeeper为注册中心，深入了解服务调用方消费者注册以及调用所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。
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