dubbo的consumer由ReferenceBean初始化，我们先来看一下这个类的层次结构：
我们看到ReferenceBean实现了InitializingBean，所以我们先来看一下它的afterPropertiesSet方法实现：
ReferenceBean：
public void afterPropertiesSet() throws Exception {
// ConsumerConfig配置
if (getConsumer() == null) {
Map<String, ConsumerConfig> consumerConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ConsumerConfig.class, false, false);
if (consumerConfigMap != null && consumerConfigMap.size() > 0) {
ConsumerConfig consumerConfig = null;
for (ConsumerConfig config : consumerConfigMap.values()) {
if (config.isDefault() == null || config.isDefault().booleanValue()) {
if (consumerConfig != null) {
throw new IllegalStateException("Duplicate consumer configs: " + consumerConfig + " and " + config);
}
consumerConfig = config;
}
}
if (consumerConfig != null) {
setConsumer(consumerConfig);
}
}
}
// ApplicationConfig配置
if (getApplication() == null
&& (getConsumer() == null || getConsumer().getApplication() == null)) {
Map<String, ApplicationConfig> applicationConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ApplicationConfig.class, false, false);
if (applicationConfigMap != null && applicationConfigMap.size() > 0) {
ApplicationConfig applicationConfig = null;
for (ApplicationConfig config : applicationConfigMap.values()) {
if (config.isDefault() == null || config.isDefault().booleanValue()) {
if (applicationConfig != null) {
throw new IllegalStateException("Duplicate application configs: " + applicationConfig + " and " + config);
}
applicationConfig = config;
}
}
if (applicationConfig != null) {
setApplication(applicationConfig);
}
}
}
// ModuleConfig配置
if (getModule() == null
&& (getConsumer() == null || getConsumer().getModule() == null)) {
Map<String, ModuleConfig> moduleConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ModuleConfig.class, false, false);
if (moduleConfigMap != null && moduleConfigMap.size() > 0) {
ModuleConfig moduleConfig = null;
for (ModuleConfig config : moduleConfigMap.values()) {
if (config.isDefault() == null || config.isDefault().booleanValue()) {
if (moduleConfig != null) {
throw new IllegalStateException("Duplicate module configs: " + moduleConfig + " and " + config);
}
moduleConfig = config;
}
}
if (moduleConfig != null) {
setModule(moduleConfig);
}
}
}
// RegistryConfig配置
if ((getRegistries() == null || getRegistries().size() == 0)
&& (getConsumer() == null || getConsumer().getRegistries() == null || getConsumer().getRegistries().size() == 0)
&& (getApplication() == null || getApplication().getRegistries() == null || getApplication().getRegistries().size() == 0)) {
Map<String, RegistryConfig> registryConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, RegistryConfig.class, false, false);
if (registryConfigMap != null && registryConfigMap.size() > 0) {
List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();
for (RegistryConfig config : registryConfigMap.values()) {
if (config.isDefault() == null || config.isDefault().booleanValue()) {
registryConfigs.add(config);
}
}
if (registryConfigs != null && registryConfigs.size() > 0) {
super.setRegistries(registryConfigs);
}
}
}
// MonitorConfig配置
if (getMonitor() == null
&& (getConsumer() == null || getConsumer().getMonitor() == null)
&& (getApplication() == null || getApplication().getMonitor() == null)) {
Map<String, MonitorConfig> monitorConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, MonitorConfig.class, false, false);
if (monitorConfigMap != null && monitorConfigMap.size() > 0) {
MonitorConfig monitorConfig = null;
for (MonitorConfig config : monitorConfigMap.values()) {
if (config.isDefault() == null || config.isDefault().booleanValue()) {
if (monitorConfig != null) {
throw new IllegalStateException("Duplicate monitor configs: " + monitorConfig + " and " + config);
}
monitorConfig = config;
}
}
if (monitorConfig != null) {
setMonitor(monitorConfig);
}
}
}
Boolean b = isInit();
if (b == null && getConsumer() != null) {
b = getConsumer().isInit();
}
if (b != null && b.booleanValue()) {
/* 非延迟初始化直接进行初始化 */
getObject();
}
}
ReferenceBean：
public Object getObject() throws Exception { return get(); }
ReferenceConfig：
public synchronized T get() {
if (destroyed) {
throw new IllegalStateException("Already destroyed!");
}
if (ref == null) {
init(); /* 初始化 */
}
return ref;
}
ReferenceConfig：
private void init() {
if (initialized) {
return;
}
initialized = true;
if (interfaceName == null || interfaceName.length() == 0) {
throw new IllegalStateException("<dubbo:reference interface="" /> interface not allow null!");
}
// 获取consumer全局配置
checkDefault();
// 追加properties配置，我们在provider初始化的文章中分析过，复用的是相同的方法
appendProperties(this);
if (getGeneric() == null && getConsumer() != null) {
setGeneric(getConsumer().getGeneric());
}
if (ProtocolUtils.isGeneric(getGeneric())) {
// 泛化服务
interfaceClass = GenericService.class;
} else {
try {
interfaceClass = Class.forName(interfaceName, true, Thread.currentThread()
.getContextClassLoader());
} catch (ClassNotFoundException e) {
throw new IllegalStateException(e.getMessage(), e);
}
// 检查接口和方法，方法在接口中是否存在
checkInterfaceAndMethods(interfaceClass, methods);
}
// 解析文件的应用
String resolve = System.getProperty(interfaceName);
String resolveFile = null;
if (resolve == null || resolve.length() == 0) {
resolveFile = System.getProperty("dubbo.resolve.file");
if (resolveFile == null || resolveFile.length() == 0) {
File userResolveFile = new File(new File(System.getProperty("user.home")), "dubbo-resolve.properties");
if (userResolveFile.exists()) {
resolveFile = userResolveFile.getAbsolutePath();
}
}
if (resolveFile != null && resolveFile.length() > 0) {
Properties properties = new Properties();
FileInputStream fis = null;
try {
fis = new FileInputStream(new File(resolveFile));
properties.load(fis);
} catch (IOException e) {
throw new IllegalStateException("Unload " + resolveFile + ", cause: " + e.getMessage(), e);
} finally {
try {
if (null != fis) fis.close();
} catch (IOException e) {
logger.warn(e.getMessage(), e);
}
}
resolve = properties.getProperty(interfaceName);
}
}
if (resolve != null && resolve.length() > 0) {
url = resolve;
if (logger.isWarnEnabled()) {
if (resolveFile != null && resolveFile.length() > 0) {
logger.warn("Using default dubbo resolve file " + resolveFile + " replace " + interfaceName + "" + resolve + " to p2p invoke remote service.");
} else {
logger.warn("Using -D" + interfaceName + "=" + resolve + " to p2p invoke remote service.");
}
}
}
// 最终确定各个配置对象
if (consumer != null) {
if (application == null) {
application = consumer.getApplication();
}
if (module == null) {
module = consumer.getModule();
}
if (registries == null) {
registries = consumer.getRegistries();
}
if (monitor == null) {
monitor = consumer.getMonitor();
}
}
if (module != null) {
if (registries == null) {
registries = module.getRegistries();
}
if (monitor == null) {
monitor = module.getMonitor();
}
}
if (application != null) {
if (registries == null) {
registries = application.getRegistries();
}
if (monitor == null) {
monitor = application.getMonitor();
}
}
// 检查application配置，分析provider初始化时分析过
checkApplication();
// 检查stub、mock配置，分析provider初始化时分析过
checkStubAndMock(interfaceClass);
Map<String, String> map = new HashMap<String, String>();
// 属性map
Map<Object, Object> attributes = new HashMap<Object, Object>();
map.put(Constants.SIDE_KEY, Constants.CONSUMER_SIDE);
map.put(Constants.DUBBO_VERSION_KEY, Version.getVersion());
map.put(Constants.TIMESTAMP_KEY, String.valueOf(System.currentTimeMillis()));
if (ConfigUtils.getPid() > 0) {
map.put(Constants.PID_KEY, String.valueOf(ConfigUtils.getPid()));
}
if (!isGeneric()) {
// 校对接口版本
String revision = Version.getVersion(interfaceClass, version);
if (revision != null && revision.length() > 0) {
map.put("revision", revision);
}
// 方法列表
String[] methods = Wrapper.getWrapper(interfaceClass).getMethodNames();
if (methods.length == 0) {
logger.warn("NO method found in service interface " + interfaceClass.getName());
map.put("methods", Constants.ANY_VALUE);
} else {
map.put("methods", StringUtils.join(new HashSet<String>(Arrays.asList(methods)), ","));
}
}
map.put(Constants.INTERFACE_KEY, interfaceName);
// 为一些配置对象追加参数，分析provider初始化时分析过
appendParameters(map, application);
appendParameters(map, module);
appendParameters(map, consumer, Constants.DEFAULT_KEY);
appendParameters(map, this);
String prifix = StringUtils.getServiceKey(map);
if (methods != null && methods.size() > 0) {
for (MethodConfig method : methods) {
appendParameters(map, method, method.getName());
String retryKey = method.getName() + ".retry";
if (map.containsKey(retryKey)) {
String retryValue = map.remove(retryKey);
if ("false".equals(retryValue)) {
// retry配置为false默认重试0次
map.put(method.getName() + ".retries", "0");
}
}
appendAttributes(attributes, method, prifix + "." + method.getName());
// 检查配置冲突，将onreturn、onthrow、oninvoke方法名转换为方法
checkAndConvertImplicitConfig(method, map, attributes);
}
}
// 确定用于注册的ip
String hostToRegistry = ConfigUtils.getSystemProperty(Constants.DUBBO_IP_TO_REGISTRY);
if (hostToRegistry == null || hostToRegistry.length() == 0) {
hostToRegistry = NetUtils.getLocalHost();
} else if (isInvalidLocalHost(hostToRegistry)) {
throw new IllegalArgumentException("Specified invalid registry ip from property:" + Constants.DUBBO_IP_TO_REGISTRY + ", value:" + hostToRegistry);
}
map.put(Constants.REGISTER_IP_KEY, hostToRegistry);
// 属性保存到系统上下文中
StaticContext.getSystemContext().putAll(attributes);
/* 创建代理 */
ref = createProxy(map);
// 获取唯一服务名称（由group分组、接口名称和版本拼接而成），创建consumer模型
ConsumerModel consumerModel = new ConsumerModel(getUniqueServiceName(), this, ref, interfaceClass.getMethods());
// 添加唯一服务名称和consumer模型的映射
ApplicationModel.initConsumerModel(getUniqueServiceName(), consumerModel);
}}
这里有一些方法我们在分析provider初始化源码的时候分析过，这里就不再重复了，复用的相同的流程。
ReferenceConfig：
private T createProxy(Map<String, String> map) {
URL tmpUrl = new URL("temp", "localhost", 0, map);
final boolean isJvmRefer;
if (isInjvm() == null) {
// 如果指定了URL，不要做本地引用
if (url != null && url.length() > 0) {
isJvmRefer = false;
} else if (InjvmProtocol.getInjvmProtocol().isInjvmRefer(tmpUrl)) {
// 默认情况下，引用本地服务，如果存在
isJvmRefer = true;
} else {
isJvmRefer = false;
}
} else {
isJvmRefer = isInjvm().booleanValue();
}
if (isJvmRefer) {
URL url = new URL(Constants.LOCAL_PROTOCOL, NetUtils.LOCALHOST, 0, interfaceClass.getName()).addParameters(map);
// InjvmProtocol做本地引用
invoker = refprotocol.refer(interfaceClass, url);
if (logger.isInfoEnabled()) {
logger.info("Using injvm service " + interfaceClass.getName());
}
} else {
// 用户指定的URL，可以是点对点地址，也可以是注册中心的地址
if (url != null && url.length() > 0) {
String[] us = Constants.SEMICOLON_SPLIT_PATTERN.split(url);
if (us != null && us.length > 0) {
for (String u : us) {
URL url = URL.valueOf(u);
if (url.getPath() == null || url.getPath().length() == 0) {
url = url.setPath(interfaceName);
}
if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {
urls.add(url.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map)));
} else {
urls.add(ClusterUtils.mergeUrl(url, map));
}
}
}
// 从注册中心的配置组合URL
} else {
// 加载注册中心配置，provider初始化文章中分析过
List<URL> us = loadRegistries(false);
if (us != null && us.size() > 0) {
for (URL u : us) {
// 加载监控中心地址
URL monitorUrl = loadMonitor(u);
if (monitorUrl != null) {
map.put(Constants.MONITOR_KEY, URL.encode(monitorUrl.toFullString()));
}
urls.add(u.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map)));
}
}
if (urls == null || urls.size() == 0) {
throw new IllegalStateException("No such any registry to reference " + interfaceName + " on the consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() + ", please config <dubbo:registry address="..." /> to your spring config.");
}
}
if (urls.size() == 1) {
/* 单个url直接关联引用 */
invoker = refprotocol.refer(interfaceClass, urls.get(0));
} else {
List<Invoker<?>> invokers = new ArrayList<Invoker<?>>();
URL registryURL = null;
for (URL url : urls) {
/* 多个url循环关联引用返回invoker */
invokers.add(refprotocol.refer(interfaceClass, url));
if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {
registryURL = url; // 使用最后一个注册中心url
}
}
if (registryURL != null) {
// 仅在register的群集可用时才使用AvailableCluster
URL u = registryURL.addParameter(Constants.CLUSTER_KEY, AvailableCluster.NAME);
// AvailableCluster
invoker = cluster.join(new StaticDirectory(u, invokers));
} else {
// 不是一个注册中心url
invoker = cluster.join(new StaticDirectory(invokers));
}
}
}
Boolean c = check;
if (c == null && consumer != null) {
c = consumer.isCheck();
}
if (c == null) {
c = true; // 默认要检查关联服务的provider是否存在
}
if (c && !invoker.isAvailable()) {
throw new IllegalStateException("Failed to check the status of the service " + interfaceName + ". No provider available for the service " + (group == null ? "" : group + "/") + interfaceName + (version == null ? "" : ":" + version) + " from the url " + invoker.getUrl() + " to the consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion());
}
if (logger.isInfoEnabled()) {
logger.info("Refer dubbo service " + interfaceClass.getName() + " from url " + invoker.getUrl());
}
// javaassist生成动态代理类
return (T) proxyFactory.getProxy(invoker);
}}
RegistryProtocol：
public <T> Invoker<T> refer(Class<T> type, URL url) throws RpcException {
url = url.setProtocol(url.getParameter(Constants.REGISTRY_KEY, Constants.DEFAULT_REGISTRY)).removeParameter(Constants.REGISTRY_KEY);
// 获取注册中心对象
Registry registry = registryFactory.getRegistry(url);
if (RegistryService.class.equals(type)) {
return proxyFactory.getInvoker((T) registry, type, url);
}
// group="a,b" or group="*"
Map<String, String> qs = StringUtils.parseQueryString(url.getParameterAndDecoded(Constants.REFER_KEY));
String group = qs.get(Constants.GROUP_KEY);
if (group != null && group.length() > 0) {
// 多个分组或者是通配符分组的处理
if ((Constants.COMMA_SPLIT_PATTERN.split(group)).length > 1
|| "*".equals(group)) {
/* 关联服务引用 */
return doRefer(getMergeableCluster(), registry, type, url);
}
}
/* 关联服务引用 */
return doRefer(cluster, registry, type, url);
}
关于注册中心的相关操作，我们在Dubbo源码解析之registry注册中心这篇文章中已经分析过，这里不再赘述。
RegistryProtocol：
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);
Map<String, String> parameters = new HashMap<String, String>(directory.getUrl().getParameters());
URL subscribeUrl = new URL(Constants.CONSUMER_PROTOCOL, parameters.remove(Constants.REGISTER_IP_KEY), 0, type.getName(), parameters);
if (!Constants.ANY_VALUE.equals(url.getServiceInterface())
&& url.getParameter(Constants.REGISTER_KEY, true)) {
// 注册中心注册成为消费者
registry.register(subscribeUrl.addParameters(Constants.CATEGORY_KEY, Constants.CONSUMERS_CATEGORY,
Constants.CHECK_KEY, String.valueOf(false)));
}
// 订阅注册中心中服务的提供者、配置、和路由等相关信息
directory.subscribe(subscribeUrl.addParameter(Constants.CATEGORY_KEY,
Constants.PROVIDERS_CATEGORY
+ "," + Constants.CONFIGURATORS_CATEGORY
+ "," + Constants.ROUTERS_CATEGORY));
// 多分组为MergeableCluster，单分组默认为FailoverCluster
// 分别返回的Invoker就是MergeableClusterInvoker和FailoverClusterInvoker
Invoker invoker = cluster.join(directory);
/* 注册consumer */
ProviderConsumerRegTable.registerConsuemr(invoker, url, subscribeUrl, directory);
return invoker;
}
ProviderConsumerRegTable：
public static void registerConsuemr(Invoker invoker, URL registryUrl, URL consumerUrl, RegistryDirectory registryDirectory) {
// 构建包装类
ConsumerInvokerWrapper wrapperInvoker = new ConsumerInvokerWrapper(invoker, registryUrl, consumerUrl, registryDirectory);
String serviceUniqueName = consumerUrl.getServiceKey();
// 从服务唯一名称和invoker集合的映射中获取invoker集合
Set<ConsumerInvokerWrapper> invokers = consumerInvokers.get(serviceUniqueName);
if (invokers == null) {
// 获取不到添加新的集合
consumerInvokers.putIfAbsent(serviceUniqueName, new ConcurrentHashSet<ConsumerInvokerWrapper>());
invokers = consumerInvokers.get(serviceUniqueName);
}
// 包装类放入集合
invokers.add(wrapperInvoker);
}
到这里，整个consumer初始化流程就分析完成了。