dubbo基於spring的構建分析
dubbo是基於spring構建和運行的，兼容spring配置。這篇說說dubbo基於spring的過程。
dubbo首先利用了從spring2.0開始的一個特性，Extensible XML authoring，擴展spring了標籤功能。
關於如何利用spring擴展本身的標籤，能夠參考下官方介紹
https://docs.spring.io/spring/docs/3.2.18.RELEASE/spring-framework-reference/htmlsingle/#extensible-xml
根據文檔的說法，須要以下4步：
1，編寫xml，描述須要擴展的標籤的配置屬性，dubbo實現放在jar包META-INF/dubbo.xsd文件裏
同時經過編寫META-INF/spring.handlers文件，提供給spring，內容以下
http\://code.alibabatech.com/schema/dubbo/dubbo.xsd=META-INF/dubbo.xsd
xsd文件也很好編寫閱讀，裏面有繼承和嵌套的概念。
2，寫一個NamespaceHandler接口實現類，dubbo的實現類是DubboNamespaceHandler
同時經過編寫META-INF/spring.schemas文件，提供給spring，內容以下：
http\://code.alibabatech.com/schema/dubbo=com.alibaba.dubbo.config.spring.schema.DubboNamespaceHandler
3，編寫一個（或者多個）BeanDefinitionParser實現類，用來解析擴展的元素，dubbo實現類是DubboBeanDefinitionParser，
這個類也是真正的須要本身處理的代碼所在。
4，把以上組件註冊給spirng，這個dubbo其實在DubboNamespaceHandler類裏。html
DubboNamespaceHandler類實現：
public class DubboNamespaceHandler extends NamespaceHandlerSupport {
static {
Version.checkDuplicate(DubboNamespaceHandler.class);
}
public void init() {
//設置每一個擴展標籤對應解析類，並註冊擴展的10個標籤
registerBeanDefinitionParser("application", new DubboBeanDefinitionParser(ApplicationConfig.class, true));
registerBeanDefinitionParser("module", new DubboBeanDefinitionParser(ModuleConfig.class, true));
registerBeanDefinitionParser("registry", new DubboBeanDefinitionParser(RegistryConfig.class, true));
registerBeanDefinitionParser("monitor", new DubboBeanDefinitionParser(MonitorConfig.class, true));
registerBeanDefinitionParser("provider", new DubboBeanDefinitionParser(ProviderConfig.class, true));
registerBeanDefinitionParser("consumer", new DubboBeanDefinitionParser(ConsumerConfig.class, true));
registerBeanDefinitionParser("protocol", new DubboBeanDefinitionParser(ProtocolConfig.class, true));
registerBeanDefinitionParser("service", new DubboBeanDefinitionParser(ServiceBean.class, true));
registerBeanDefinitionParser("reference", new DubboBeanDefinitionParser(ReferenceBean.class, false));
registerBeanDefinitionParser("annotation", new DubboBeanDefinitionParser(AnnotationBean.class, true));
}
}
完成以上事情，spring就能識別dubbo的擴展標籤了。下面分別從代碼層面看看具體實現。java
上面提到的10個擴展標籤，分別對應10個配置類。類的層次關係：
主要基類是AbstractConfig和AbstractMethodConfig，而AbstractConfig又是全部類的基類。
這10個配置類中ReferenceBean，ServiceBean，AnnotationBean 3個類又都實現了若干spring接口，這3個類算是利用spring完成dubbo調用的驅動類，後面要分別看源碼。node
DubboBeanDefinitionParser類
這個類實現了BeanDefinitionParser接口，這是個spring的原生接口，裏面只有一個方法
public interface BeanDefinitionParser {
BeanDefinition parse(Element element, ParserContext parserContext);
}
根據接口定義，這個方法實現，須要解析Element元素成原生的BeanDefinition類對象，而後利用
ParserContext對象的getRegistry()返回的註冊器來註冊解析後BeanDefinition類對象，
最後返回這個BeanDefinition類對象。下面是dubbo的實現，它主要完成spring配置到spring容器內部BeanDefinition轉化過程。代碼：spring
private static BeanDefinition parse(Element element, ParserContext parserContext, Class<?> beanClass, boolean required) {
// new RootBeanDefinition 對象，做爲註冊和返回的對象
RootBeanDefinition beanDefinition = new RootBeanDefinition();
//設置class
beanDefinition.setBeanClass(beanClass);//
beanDefinition.setLazyInit(false);
String id = element.getAttribute("id");//獲取id
if ((id == null || id.length() == 0) && required) {
//沒法獲取id的按策略生成id
String generatedBeanName = element.getAttribute("name");
if (generatedBeanName == null || generatedBeanName.length() == 0) {
if (ProtocolConfig.class.equals(beanClass)) {
//ProtocolConfig 類型爲dubbo開頭
generatedBeanName = "dubbo";
} else {
generatedBeanName = element.getAttribute("interface");
}
}
if (generatedBeanName == null || generatedBeanName.length() == 0) {
generatedBeanName = beanClass.getName();
}
id = generatedBeanName;
int counter = 2;
//id 爲name1,name2 形式，檢測id 是否存在，存在id，序號自增
while (parserContext.getRegistry().containsBeanDefinition(id)) {
id = generatedBeanName + (counter++);
}
}
if (id != null && id.length() > 0) {
if (parserContext.getRegistry().containsBeanDefinition(id)) {
throw new IllegalStateException("Duplicate spring bean id " + id);
}
//利用parserContext.getRegistry()註冊beanDefinition
parserContext.getRegistry().registerBeanDefinition(id, beanDefinition);
//這是beanDefinition id屬性
beanDefinition.getPropertyValues().addPropertyValue("id", id);
}
//把全部protocol屬性name等於id&&類型是ProtocolConfig的
// protocol 屬性設置爲 new RuntimeBeanReference(id)，應用當前BeanDefinition
if (ProtocolConfig.class.equals(beanClass)) {
for (String name : parserContext.getRegistry().getBeanDefinitionNames()) {
BeanDefinition definition = parserContext.getRegistry().getBeanDefinition(name);
PropertyValue property = definition.getPropertyValues().getPropertyValue("protocol");
if (property != null) {
Object value = property.getValue();
if (value instanceof ProtocolConfig && id.equals(((ProtocolConfig) value).getName())) {
definition.getPropertyValues().addPropertyValue("protocol", new RuntimeBeanReference(id));
}
}
}
} else if (ServiceBean.class.equals(beanClass)) {
//直接指定class的方式
String className = element.getAttribute("class");
if (className != null && className.length() > 0) {
RootBeanDefinition classDefinition = new RootBeanDefinition();
//利用反射有類名獲得class
classDefinition.setBeanClass(ReflectUtils.forName(className));
classDefinition.setLazyInit(false);
//解析property
parseProperties(element.getChildNodes(), classDefinition);
//把serviceBean 的ref 屬性設置爲指向class類
beanDefinition.getPropertyValues().addPropertyValue("ref", new BeanDefinitionHolder(classDefinition, id + "Impl"));
}
} else if (ProviderConfig.class.equals(beanClass)) {
//proivder的配置 做爲ServiceBean 的設置
parseNested(element, parserContext, ServiceBean.class, true, "service", "provider", id, beanDefinition);
} else if (ConsumerConfig.class.equals(beanClass)) {
// consumer的配置 做爲ReferenceBean 的設置
parseNested(element, parserContext, ReferenceBean.class, false, "reference", "consumer", id, beanDefinition);
}
Set<String> props = new HashSet<String>();
ManagedMap parameters = null;
for (Method setter : beanClass.getMethods()) {
String name = setter.getName();
if (name.length() > 3 && name.startsWith("set")
&& Modifier.isPublic(setter.getModifiers())
&& setter.getParameterTypes().length == 1) {
//全部只有一個參數的set方法
//set方法參數類型
Class<?> type = setter.getParameterTypes()[0];
//abCdEF --> ab-cd-ef 駝峯命名轉換 - 分割
String property = StringUtils.camelToSplitName(name.substring(3, 4).toLowerCase() + name.substring(4), "-");
props.add(property);
Method getter = null;
//獲取 對應public getter 方法
try {
getter = beanClass.getMethod("get" + name.substring(3), new Class<?>[0]);
} catch (NoSuchMethodException e) {
try {
getter = beanClass.getMethod("is" + name.substring(3), new Class<?>[0]);
} catch (NoSuchMethodException e2) {
}
}
if (getter == null
|| !Modifier.isPublic(getter.getModifiers())
|| !type.equals(getter.getReturnType())) {
continue;
}
if ("parameters".equals(property)) {//有parameters屬性，解析元素的全部parameter元素
parameters = parseParameters(element.getChildNodes(), beanDefinition);
} else if ("methods".equals(property)) {//有methods屬性，就解析配置元素的全部method元素 放到beanDefinition 「methods」 配置裏
parseMethods(id, element.getChildNodes(), beanDefinition, parserContext);
} else if ("arguments".equals(property)) {//有arguments屬性，就解析全部的argument元素
parseArguments(id, element.getChildNodes(), beanDefinition, parserContext);
} else {
String value = element.getAttribute(property);
if (value != null) {
value = value.trim();
if (value.length() > 0) {
if ("registry".equals(property) && RegistryConfig.NO_AVAILABLE.equalsIgnoreCase(value)) {
RegistryConfig registryConfig = new RegistryConfig();
registryConfig.setAddress(RegistryConfig.NO_AVAILABLE);
beanDefinition.getPropertyValues().addPropertyValue(property, registryConfig);
} else if ("registry".equals(property) && value.indexOf(',') != -1) {
//解析多個以逗號分割的多個registry配置 放到 beanDefinition registries屬性裏
parseMultiRef("registries", value, beanDefinition, parserContext);
} else if ("provider".equals(property) && value.indexOf(',') != -1) {
//解析多個以逗號分割的多個provider配置 放到 beanDefinition providers屬性裏
parseMultiRef("providers", value, beanDefinition, parserContext);
} else if ("protocol".equals(property) && value.indexOf(',') != -1) {
//解析多個以逗號分割的多個protocol配置 放到 beanDefinition protocols屬性裏
parseMultiRef("protocols", value, beanDefinition, parserContext);
} else {
Object reference;
if (isPrimitive(type)) {//set 方法參數是方法指定的原始類型
if ("async".equals(property) && "false".equals(value)
|| "timeout".equals(property) && "0".equals(value)
|| "delay".equals(property) && "0".equals(value)
|| "version".equals(property) && "0.0.0".equals(value)
|| "stat".equals(property) && "-1".equals(value)
|| "reliable".equals(property) && "false".equals(value)) {
// 兼容舊版本xsd中的default值
value = null;
}
//直接賦值
reference = value;
} else if ("protocol".equals(property)
&& ExtensionLoader.getExtensionLoader(Protocol.class).hasExtension(value)
&& (!parserContext.getRegistry().containsBeanDefinition(value)
|| !ProtocolConfig.class.getName().equals(parserContext.getRegistry().getBeanDefinition(value).getBeanClassName()))) {
if ("dubbo:provider".equals(element.getTagName())) {
logger.warn("Recommended replace <dubbo:provider protocol=\"" + value + "\" ... /> to <dubbo:protocol name=\"" + value + "\" ... />");
}
//兼容舊版本配置
ProtocolConfig protocol = new ProtocolConfig();
protocol.setName(value);
reference = protocol;
} else if ("monitor".equals(property)
&& (!parserContext.getRegistry().containsBeanDefinition(value)
|| !MonitorConfig.class.getName().equals(parserContext.getRegistry().getBeanDefinition(value).getBeanClassName()))) {
//兼容舊版本配置
reference = convertMonitor(value);
} else if ("onreturn".equals(property)) {//回調函數設置 service.ontrenMethod
int index = value.lastIndexOf(".");
String returnRef = value.substring(0, index);
String returnMethod = value.substring(index + 1);
reference = new RuntimeBeanReference(returnRef);
beanDefinition.getPropertyValues().addPropertyValue("onreturnMethod", returnMethod);
} else if ("onthrow".equals(property)) {
int index = value.lastIndexOf(".");
String throwRef = value.substring(0, index);
String throwMethod = value.substring(index + 1);
reference = new RuntimeBeanReference(throwRef);
beanDefinition.getPropertyValues().addPropertyValue("onthrowMethod", throwMethod);
} else {//解析ref 屬性
if ("ref".equals(property) && parserContext.getRegistry().containsBeanDefinition(value)) {
BeanDefinition refBean = parserContext.getRegistry().getBeanDefinition(value);
if (!refBean.isSingleton()) {
throw new IllegalStateException("The exported service ref " + value + " must be singleton! Please set the " + value + " bean scope to singleton, eg: <bean id=\"" + value + "\" scope=\"singleton\" ...>");
}
}
reference = new RuntimeBeanReference(value);
}
beanDefinition.getPropertyValues().addPropertyValue(property, reference);
}
}
}
}
}
}
//element 自己全部屬性 放入beanDefinition的parameters
NamedNodeMap attributes = element.getAttributes();
int len = attributes.getLength();
for (int i = 0; i < len; i++) {
Node node = attributes.item(i);
String name = node.getLocalName();
if (!props.contains(name)) {
if (parameters == null) {
parameters = new ManagedMap();
}
String value = node.getNodeValue();
parameters.put(name, new TypedStringValue(value, String.class));
}
}
if (parameters != null) {
beanDefinition.getPropertyValues().addPropertyValue("parameters", parameters);
}
return beanDefinition;
}
ReferenceBean類
ReferenceBean類主要完成在適當的時機（spring bean初始化完成，或者用戶經過spring容器獲取bean）
根據服務調用方配置，生成服務調用代理的工做。api
ReferenceBean繼承類層：app
能夠看到，ReferenceBean及其基類實現了FactoryBean, ApplicationContextAware, InitializingBean, DisposableBean 4個接口的方法，
經過spring回調機制，完成spring容器傳入，獲取bean類型，bean初始化和destory定製等操做。ReferenceBean類裏具體方法實現：async
/***
* 實現ApplicationContextAware接口方法。在bean初始化時，回傳bean所在容器的引用
* @param applicationContext
*/
public void setApplicationContext(ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
//容器引用，傳入SpringExtensionFactory
SpringExtensionFactory.addApplicationContext(applicationContext);
}
/***
* 實現FactoryBean接口方法，
* 返回一個bean實例,在使用spring api 向容器獲取一個bean時調用
* 這裏返回的是reference代理
* @return
* @throws Exception
*/
public Object getObject() throws Exception {
return get();
}
/***
* 實現FactoryBean接口方法，
* 返回一個bean的類型
* @return
*/
public Class<?> getObjectType() {
return getInterfaceClass();
}
/***
* 實現FactoryBean接口方法，
* 返回一個bean的是不是單例
* @return
*/
@Parameter(excluded = true)
public boolean isSingleton() {
return true;
}
/***
* 實現InitializingBean接口方法，
* 在bean 全部（提供的）屬性值都賦值後，由spring回調執行
* 這個方法裏能夠作些初始化定製
* @throws Exception
*/
@SuppressWarnings({"unchecked"})
public void afterPropertiesSet() throws Exception {
if (getConsumer() == null) {
//BeanFactoryUtils.beansOfTypeIncludingAncestors是spring的一個工具類，
// 它返回指定容器裏，ConsumerConfig.class類及其子類的bean，若是還沒初始化，會觸發初始化的過程，依賴注入的概念
Map<String, ConsumerConfig> consumerConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ConsumerConfig.class, false, false);
if (consumerConfigMap != null && consumerConfigMap.size() > 0) {
ConsumerConfig consumerConfig = null;
//遍歷map 默認設置ConsumerConfig
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;
}
}
//設置ConsumerConfig
if (consumerConfig != null) {
setConsumer(consumerConfig);
}
}
}
//設置ApplicationConfig
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);
}
}
}
//設置ModuleConfig
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);
}
}
}
//註冊中心能夠有多個
if ((getRegistries() == null || getRegistries().size() == 0)
&& (getConsumer() == null || getConsumer().getRegistries() == null || getConsumer().getRegistries().size() == 0)
&& (getApplication() == null || getApplication().getRegistries() == null || getApplication().getRegistries().size() == 0)) {
//多個註冊中心
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);
}
}
}
//設置監控中心
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);
}
}
}
//是否bean建立後就初始化代理
Boolean b = isInit();
if (b == null && getConsumer() != null) {
b = getConsumer().isInit();
}
if (b != null && b.booleanValue()) {//當即初始化代理
getObject();
}
}
ServiceBean類
ServiceBean類主要完成，在適當的時機（spring 容器初始化完成或者服務實例初始化完成）根據服務提供方配置暴露發佈服務的工做。ServiceBean類繼承層以下：ide
能夠看到ServiceBean及其基類實現了InitializingBean, DisposableBean, ApplicationContextAware, ApplicationListener, BeanNameAware接口
經過spring回調機制完成spring容器引用傳入，bean初始化和destory過程定製，以及監聽並處理spring事件的操做。ServiceBean類具體方法實現：函數
/***
* ApplicationContextAware接口方法，
* 傳入bean 所在容器引用
* @param applicationContext
*/
public void setApplicationContext(ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
//把spring 容器傳入SpringExtensionFactory
SpringExtensionFactory.addApplicationContext(applicationContext);
//獲取容器addApplicationListener方法，把當前類加入到容器監聽器隊列
if (applicationContext != null) {
SPRING_CONTEXT = applicationContext;
try {
Method method = applicationContext.getClass().getMethod("addApplicationListener", new Class<?>[]{ApplicationListener.class}); // 兼容Spring2.0.1
method.invoke(applicationContext, new Object[]{this});
supportedApplicationListener = true;
} catch (Throwable t) {
if (applicationContext instanceof AbstractApplicationContext) {
try {
Method method = AbstractApplicationContext.class.getDeclaredMethod("addListener", new Class<?>[]{ApplicationListener.class}); // 兼容Spring2.0.1
if (!method.isAccessible()) {
method.setAccessible(true);
}
method.invoke(applicationContext, new Object[]{this});
supportedApplicationListener = true;
} catch (Throwable t2) {
}
}
}
}
}
/***
* BeanNameAware接口方法，設置beanName值
* @param name
*/
public void setBeanName(String name) {
this.beanName = name;
}
/***
* 實現ApplicationListener接口方法，
* 本方法會接受並處理在容器初始化完成時發佈的ContextRefreshedEvent事件，
* 即容器初始化完成後 暴露服務
* @param event
*/
public void onApplicationEvent(ApplicationEvent event) {
if (ContextRefreshedEvent.class.getName().equals(event.getClass().getName())) {
if (isDelay() && !isExported() && !isUnexported()) {
if (logger.isInfoEnabled()) {
logger.info("The service ready on spring started. service: " + getInterface());
}
//執行暴露過程
export();
}
}
}
/***
* InitializingBean 接口方法，bean 屬性初始化後，操做處理
* @throws Exception
*/
@SuppressWarnings({"unchecked", "deprecation"})
public void afterPropertiesSet() throws Exception {
//設置ProviderConfig
if (getProvider() == null) {
Map<String, ProviderConfig> providerConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProviderConfig.class, false, false);
if (providerConfigMap != null && providerConfigMap.size() > 0) {
Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false);
if ((protocolConfigMap == null || protocolConfigMap.size() == 0)
&& providerConfigMap.size() > 1) { // 兼容舊版本
List<ProviderConfig> providerConfigs = new ArrayList<ProviderConfig>();
for (ProviderConfig config : providerConfigMap.values()) {
if (config.isDefault() != null && config.isDefault().booleanValue()) {
providerConfigs.add(config);
}
}
if (providerConfigs.size() > 0) {
setProviders(providerConfigs);
}
} else {
ProviderConfig providerConfig = null;
for (ProviderConfig config : providerConfigMap.values()) {
if (config.isDefault() == null || config.isDefault().booleanValue()) {
if (providerConfig != null) {
throw new IllegalStateException("Duplicate provider configs: " + providerConfig + " and " + config);
}
providerConfig = config;
}
}
if (providerConfig != null) {
setProvider(providerConfig);
}
}
}
}
if (getApplication() == null
&& (getProvider() == null || getProvider().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);
}
}
}
if (getModule() == null
&& (getProvider() == null || getProvider().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);
}
}
}
if ((getRegistries() == null || getRegistries().size() == 0)
&& (getProvider() == null || getProvider().getRegistries() == null || getProvider().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);
}
}
}
if (getMonitor() == null
&& (getProvider() == null || getProvider().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);
}
}
}
//服務協議，能夠有多個
if ((getProtocols() == null || getProtocols().size() == 0)
&& (getProvider() == null || getProvider().getProtocols() == null || getProvider().getProtocols().size() == 0)) {
Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false);
if (protocolConfigMap != null && protocolConfigMap.size() > 0) {
List<ProtocolConfig> protocolConfigs = new ArrayList<ProtocolConfig>();
for (ProtocolConfig config : protocolConfigMap.values()) {
if (config.isDefault() == null || config.isDefault().booleanValue()) {
protocolConfigs.add(config);
}
}
if (protocolConfigs != null && protocolConfigs.size() > 0) {
super.setProtocols(protocolConfigs);
}
}
}
//設置服務路徑 類全名
if (getPath() == null || getPath().length() == 0) {
if (beanName != null && beanName.length() > 0
&& getInterface() != null && getInterface().length() > 0
&& beanName.startsWith(getInterface())) {
setPath(beanName);
}
}
//是否延遲暴露
if (!isDelay()) {
export();//暴露服務
}
}
/***
* DisposableBean接口方法，再單例bean 析構時，回調
* 回收資源，這裏調用unexport方法
* @throws Exception
*/
public void destroy() throws Exception {
unexport();
}
AnnotationBean類
這個類使得dubbo具備自動包掃描的功能，支持dubbo經過註解配置service和refernece bean（有些屬性不能註解配置），並完成ServiceBean和ReferenceBean相同的功能。類圖：工具
能夠看到AnnotationBean及其父類實現了接口DisposableBean, BeanFactoryPostProcessor, BeanPostProcessor, ApplicationContextAware一樣經過spring接口方法回調，實現bean實例的初始化預處理。
AnnotationBean類是基於ClassPathBeanDefinitionScanner類實現的。
自動包掃描先看下
org.springframework.context.annotation.ClassPathBeanDefinitionScanner類，
官方解釋：
A bean definition scanner that detects bean candidates on the classpath, registering corresponding bean definitions with a given registry (BeanFactory or ApplicationContext). Candidate classes are detected through configurable type filters. The default filters include classes that are annotated with Spring's @Component, @Repository, @Service, or @Controller stereotype.
說人話，就是ClassPathBeanDefinitionScanner會自動在classpatch裏掃描並註冊
@Component, @Repository, @Service, or @Controller的beans,至關於自動完成
上面說的DubboBeanDefinitionParser類的相似工做。這個類默認處理上面說的4種註解，
但能經過filter添加新的要掃描處理的註解。主要代碼實現：
/***
* 設置要掃描的包名，以逗號分隔多個包名
* @param annotationPackage
*/
public void setPackage(String annotationPackage) {
this.annotationPackage = annotationPackage;
this.annotationPackages = (annotationPackage == null || annotationPackage.length() == 0) ? null
: Constants.COMMA_SPLIT_PATTERN.split(annotationPackage);
}
/***
* 實現spring 回調接口方法，傳入的容器引用
* @param applicationContext
* @throws BeansException
*/
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
/***
* 實現BeanFactoryPostProcessor接口
* 這個方法會在，全部的bean definitions已加載，
* 可是還沒實例化以前回調執行
* 能夠在bean初始化以前定製化一些操做
* 這裏作的是，調用org.springframework.context.annotation.ClassPathBeanDefinitionScanner的scan方法，
* 掃描並註冊有 Service(dubbo定義) 註解的bean
* 固然都是用反射完成的
* @param beanFactory
* @throws BeansException
*/
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
throws BeansException {
if (annotationPackage == null || annotationPackage.length() == 0) {
return;
}
if (beanFactory instanceof BeanDefinitionRegistry) {
try {
// init scanner
//利用反射構造ClassPathBeanDefinitionScanner實例，用的這個構造方法，
// useDefaultFilters=true 默認掃描 spring 4種的註解
// public ClassPathBeanDefinitionScanner(BeanDefinitionRegistry registry, boolean useDefaultFilters) {
// this(registry, useDefaultFilters, getOrCreateEnvironment(registry));
// }
Class<?> scannerClass = ReflectUtils.forName("org.springframework.context.annotation.ClassPathBeanDefinitionScanner");
Object scanner = scannerClass.getConstructor(new Class<?>[]{BeanDefinitionRegistry.class, boolean.class}).newInstance(new Object[]{(BeanDefinitionRegistry) beanFactory, true});
// add filter
//經過filter 添加新要掃描的註解，也是用的反射 這裏是 AnnotationTypeFilter
Class<?> filterClass = ReflectUtils.forName("org.springframework.core.type.filter.AnnotationTypeFilter");
Object filter = filterClass.getConstructor(Class.class).newInstance(Service.class);
//獲取添加filter的方法，並調用
Method addIncludeFilter = scannerClass.getMethod("addIncludeFilter", ReflectUtils.forName("org.springframework.core.type.filter.TypeFilter"));
addIncludeFilter.invoke(scanner, filter);
// scan packages
//獲取 ClassPathBeanDefinitionScanner的 scan(java.lang.String... basePackages) 方法，開始掃描
String[] packages = Constants.COMMA_SPLIT_PATTERN.split(annotationPackage);
Method scan = scannerClass.getMethod("scan", new Class<?>[]{String[].class});
scan.invoke(scanner, new Object[]{packages});
} catch (Throwable e) {
// spring 2.0
}
}
}
/***
* 實現DisposableBean接口
* 在bean 析構時，調用相關方法，釋放資源
* @throws Exception
*/
public void destroy() throws Exception {
for (ServiceConfig<?> serviceConfig : serviceConfigs) {
try {
serviceConfig.unexport();
} catch (Throwable e) {
logger.error(e.getMessage(), e);
}
}
for (ReferenceConfig<?> referenceConfig : referenceConfigs.values()) {
try {
referenceConfig.destroy();
} catch (Throwable e) {
logger.error(e.getMessage(), e);
}
}
}
/***
* 實現BeanPostProcessor接口方法
* 在bean初始化後 好比在afterPropertiesSet後由spring回調執行
* 這個方法完成相似ServiceBean的工做
* @param bean
* @param beanName
* @return
* @throws BeansException
*/
public Object postProcessAfterInitialization(Object bean, String beanName)
throws BeansException {
//檢查是否匹配包名
if (!isMatchPackage(bean)) {
return bean;
}
//手動建立 ServiceBean 並暴露服務
Service service = bean.getClass().getAnnotation(Service.class);
if (service != null) {
ServiceBean<Object> serviceConfig = new ServiceBean<Object>(service);
serviceConfig.setRef(bean);
if (void.class.equals(service.interfaceClass())
&& "".equals(service.interfaceName())) {
if (bean.getClass().getInterfaces().length > 0) {
serviceConfig.setInterface(bean.getClass().getInterfaces()[0]);
} else {
throw new IllegalStateException("Failed to export remote service class " + bean.getClass().getName() + ", cause: The @Service undefined interfaceClass or interfaceName, and the service class unimplemented any interfaces.");
}
}
if (applicationContext != null) {
serviceConfig.setApplicationContext(applicationContext);
if (service.registry() != null && service.registry().length > 0) {
List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();
for (String registryId : service.registry()) {
if (registryId != null && registryId.length() > 0) {
registryConfigs.add((RegistryConfig) applicationContext.getBean(registryId, RegistryConfig.class));
}
}
serviceConfig.setRegistries(registryConfigs);
}
if (service.provider() != null && service.provider().length() > 0) {
serviceConfig.setProvider((ProviderConfig) applicationContext.getBean(service.provider(), ProviderConfig.class));
}
if (service.monitor() != null && service.monitor().length() > 0) {
serviceConfig.setMonitor((MonitorConfig) applicationContext.getBean(service.monitor(), MonitorConfig.class));
}
if (service.application() != null && service.application().length() > 0) {
serviceConfig.setApplication((ApplicationConfig) applicationContext.getBean(service.application(), ApplicationConfig.class));
}
if (service.module() != null && service.module().length() > 0) {
serviceConfig.setModule((ModuleConfig) applicationContext.getBean(service.module(), ModuleConfig.class));
}
if (service.provider() != null && service.provider().length() > 0) {
serviceConfig.setProvider((ProviderConfig) applicationContext.getBean(service.provider(), ProviderConfig.class));
} else {
}
if (service.protocol() != null && service.protocol().length > 0) {
List<ProtocolConfig> protocolConfigs = new ArrayList<ProtocolConfig>();
for (String protocolId : service.protocol()) {
if (protocolId != null && protocolId.length() > 0) {
protocolConfigs.add((ProtocolConfig) applicationContext.getBean(protocolId, ProtocolConfig.class));
}
}
serviceConfig.setProtocols(protocolConfigs);
}
try {
//調用ServiceBean afterPropertiesSet初始化配置
serviceConfig.afterPropertiesSet();
} catch (RuntimeException e) {
throw (RuntimeException) e;
} catch (Exception e) {
throw new IllegalStateException(e.getMessage(), e);
}
}
serviceConfigs.add(serviceConfig);
//暴露服務
serviceConfig.export();
}
return bean;
}
/***
* /***
* 實現BeanPostProcessor接口方法
* 在bean初始化前 好比在afterPropertiesSet前 由spring 回調執行
* 這個方法完成相似RefercencBean的工做
* @param bean
* @param beanName
* @return
* @throws BeansException
*/
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
if (!isMatchPackage(bean)) {
return bean;
}
//由於dubbo Reference 註解只能在類的字段，或方法上
//經過bean 的set 方法上 找duboo 註解
Method[] methods = bean.getClass().getMethods();
for (Method method : methods) {
String name = method.getName();
if (name.length() > 3 && name.startsWith("set")
&& method.getParameterTypes().length == 1
&& Modifier.isPublic(method.getModifiers())
&& !Modifier.isStatic(method.getModifiers())) {
try {
Reference reference = method.getAnnotation(Reference.class);
if (reference != null) {
Object value = refer(reference, method.getParameterTypes()[0]);
if (value != null) {
method.invoke(bean, new Object[]{value});
}
}
} catch (Throwable e) {
logger.error("Failed to init remote service reference at method " + name + " in class " + bean.getClass().getName() + ", cause: " + e.getMessage(), e);
}
}
}
//經過bean 的字段 上 找duboo 註解
Field[] fields = bean.getClass().getDeclaredFields();
for (Field field : fields) {
try {
if (!field.isAccessible()) {
field.setAccessible(true);
}
Reference reference = field.getAnnotation(Reference.class);
if (reference != null) {
Object value = refer(reference, field.getType());
if (value != null) {
field.set(bean, value);
}
}
} catch (Throwable e) {
logger.error("Failed to init remote service reference at filed " + field.getName() + " in class " + bean.getClass().getName() + ", cause: " + e.getMessage(), e);
}
}
return bean;
}
/***
* 經過解析 reference註解裏的值，去構造服務調用配置，最後調用建立代理的方法
* @param reference
* @param referenceClass
* @return
*/
private Object refer(Reference reference, Class<?> referenceClass) { //method.getParameterTypes()[0]
String interfaceName;
if (!"".equals(reference.interfaceName())) {
interfaceName = reference.interfaceName();
} else if (!void.class.equals(reference.interfaceClass())) {
interfaceName = reference.interfaceClass().getName();
} else if (referenceClass.isInterface()) {
interfaceName = referenceClass.getName();
} else {
throw new IllegalStateException("The @Reference undefined interfaceClass or interfaceName, and the property type " + referenceClass.getName() + " is not a interface.");
}
String key = reference.group() + "/" + interfaceName + ":" + reference.version();
ReferenceBean<?> referenceConfig = referenceConfigs.get(key);
if (referenceConfig == null) {
referenceConfig = new ReferenceBean<Object>(reference);
if (void.class.equals(reference.interfaceClass())
&& "".equals(reference.interfaceName())
&& referenceClass.isInterface()) {
referenceConfig.setInterface(referenceClass);
}
if (applicationContext != null) {
referenceConfig.setApplicationContext(applicationContext);
if (reference.registry() != null && reference.registry().length > 0) {
List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();
for (String registryId : reference.registry()) {
if (registryId != null && registryId.length() > 0) {
registryConfigs.add((RegistryConfig) applicationContext.getBean(registryId, RegistryConfig.class));
}
}
referenceConfig.setRegistries(registryConfigs);
}
if (reference.consumer() != null && reference.consumer().length() > 0) {
referenceConfig.setConsumer((ConsumerConfig) applicationContext.getBean(reference.consumer(), ConsumerConfig.class));
}
if (reference.monitor() != null && reference.monitor().length() > 0) {
referenceConfig.setMonitor((MonitorConfig) applicationContext.getBean(reference.monitor(), MonitorConfig.class));
}
if (reference.application() != null && reference.application().length() > 0) {
referenceConfig.setApplication((ApplicationConfig) applicationContext.getBean(reference.application(), ApplicationConfig.class));
}
if (reference.module() != null && reference.module().length() > 0) {
referenceConfig.setModule((ModuleConfig) applicationContext.getBean(reference.module(), ModuleConfig.class));
}
if (reference.consumer() != null && reference.consumer().length() > 0) {
referenceConfig.setConsumer((ConsumerConfig) applicationContext.getBean(reference.consumer(), ConsumerConfig.class));
}
try {
referenceConfig.afterPropertiesSet();
} catch (RuntimeException e) {
throw (RuntimeException) e;
} catch (Exception e) {
throw new IllegalStateException(e.getMessage(), e);
}
}
referenceConfigs.putIfAbsent(key, referenceConfig);
referenceConfig = referenceConfigs.get(key);
}
//服務調用的代理建立
return referenceConfig.get();
}
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