Spring与Dubbo整合原理与源码分析
【1】注解@EnableDubbo
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
@EnableDubboConfig // @EnableDubboConfig注解用来将properties文件中的配置项转化为对应的Bean
@DubboComponentScan // @DubboComponentScan注解用来扫描服务提供者和引用者(@Service与@Reference)
public @interface EnableDubbo {
@AliasFor(annotation = DubboComponentScan.class, attribute = "basePackages")
String[] scanBasePackages() default {};
@AliasFor(annotation = DubboComponentScan.class, attribute = "basePackageClasses")
Class<?>[] scanBasePackageClasses() default {};
@AliasFor(annotation = EnableDubboConfig.class, attribute = "multiple")
boolean multipleConfig() default true;
}
【2】注解@EnableDubboConfig
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
@Import(DubboConfigConfigurationRegistrar.class)
public @interface EnableDubboConfig {
boolean multiple() default true;
}
1）DubboConfigConfigurationRegistrar类的作用
//因为实现了ImportBeanDefinitionRegistrar接口，spring容器就会实例化该类，并且调用其registerBeanDefinitions方法；
public class DubboConfigConfigurationRegistrar implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
//执行DubboConfigConfigurationRegistrar;
AnnotationAttributes attributes = AnnotationAttributes.fromMap(
importingClassMetadata.getAnnotationAttributes(EnableDubboConfig.class.getName()));
boolean multiple = attributes.getBoolean("multiple"); //默认值是true
// Single Config Bindings
registerBeans(registry, DubboConfigConfiguration.Single.class);
if (multiple) { // Since 2.6.6 https://github.com/apache/dubbo/issues/3193
registerBeans(registry, DubboConfigConfiguration.Multiple.class);
}
}
}
2）registerBeans做了什么
public static void registerBeans(BeanDefinitionRegistry registry, Class<?>... annotatedClasses) {
if (ObjectUtils.isEmpty(annotatedClasses)) {
return;
}
...
AnnotatedBeanDefinitionReader reader = new AnnotatedBeanDefinitionReader(registry);
...
// 利用Spring中的AnnotatedBeanDefinitionReader来解析annotatedClasses
// 会解析该类上的注解，然后进行处理
reader.register(annotatedClasses);
}
3）DubboConfigConfiguration类展示
public class DubboConfigConfiguration {
/**
* Single Dubbo {@link AbstractConfig Config} Bean Binding
*/
@EnableDubboConfigBindings({
@EnableDubboConfigBinding(prefix = "dubbo.application", type = ApplicationConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.module", type = ModuleConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.registry", type = RegistryConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.protocol", type = ProtocolConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.monitor", type = MonitorConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.provider", type = ProviderConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.consumer", type = ConsumerConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.config-center", type = ConfigCenterBean.class),
@EnableDubboConfigBinding(prefix = "dubbo.metadata-report", type = MetadataReportConfig.class),
@EnableDubboConfigBinding(prefix = "dubbo.metrics", type = MetricsConfig.class)
})
public static class Single {}
/**
* Multiple Dubbo {@link AbstractConfig Config} Bean Binding
*/
@EnableDubboConfigBindings({
@EnableDubboConfigBinding(prefix = "dubbo.applications", type = ApplicationConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.modules", type = ModuleConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.registries", type = RegistryConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.protocols", type = ProtocolConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.monitors", type = MonitorConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.providers", type = ProviderConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.consumers", type = ConsumerConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.config-centers", type = ConfigCenterBean.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.metadata-reports", type = MetadataReportConfig.class, multiple = true),
@EnableDubboConfigBinding(prefix = "dubbo.metricses", type = MetricsConfig.class, multiple = true)
})
public static class Multiple {}
}
4）那么必然又会解析到@EnableDubboConfigBindings注解
//又是利用了实现了ImportBeanDefinitionRegistrar接口，在实例化该类会调用其registerBeanDefinitions方法；
public class DubboConfigBindingsRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware {
private ConfigurableEnvironment environment;
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
//执行DubboConfigBindingsRegistrar
AnnotationAttributes attributes = AnnotationAttributes.fromMap(importingClassMetadata.getAnnotationAttributes(EnableDubboConfigBindings.class.getName()));
// 拿到多个@EnableDubboConfigBinding注解
AnnotationAttributes[] annotationAttributes = attributes.getAnnotationArray("value");
DubboConfigBindingRegistrar registrar = new DubboConfigBindingRegistrar();
//将环境变量注入
registrar.setEnvironment(environment);
for (AnnotationAttributes element : annotationAttributes) {
// 逐个解析@EnableDubboConfigBinding注解，比如@EnableDubboConfigBinding(prefix = "dubbo.application", type = ApplicationConfig.class)
registrar.registerBeanDefinitions(element, registry);
}
}
@Override
public void setEnvironment(Environment environment) {
Assert.isInstanceOf(ConfigurableEnvironment.class, environment);
this.environment = (ConfigurableEnvironment) environment;
}
}
5）registrar.registerBeanDefinitions方法的调用情况
public class DubboConfigBindingRegistrar implements ImportBeanDefinitionRegistrar, EnvironmentAware {
private final Log log = LogFactory.getLog(getClass());
private ConfigurableEnvironment environment;
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
//执行DubboConfigBindingRegistrar
AnnotationAttributes attributes = AnnotationAttributes.fromMap(importingClassMetadata.getAnnotationAttributes(EnableDubboConfigBinding.class.getName()));
registerBeanDefinitions(attributes, registry);
}
protected void registerBeanDefinitions(AnnotationAttributes attributes, BeanDefinitionRegistry registry) {
// prefix = "dubbo.application"
String prefix = environment.resolvePlaceholders(attributes.getString("prefix"));
// type = ApplicationConfig.class
Class<? extends AbstractConfig> configClass = attributes.getClass("type");
boolean multiple = attributes.getBoolean("multiple");
//针对配置分别进行注册成Bean对象，方法1
registerDubboConfigBeans(prefix, configClass, multiple, registry);
}
//方法1，因为Single和Multiple都是走同一套逻辑，采用参数boolean multiple区分
private void registerDubboConfigBeans(String prefix, Class<? extends AbstractConfig> configClass, boolean multiple, BeanDefinitionRegistry registry) {
// 从properties文件中根据前缀拿对应的配置项，比如根据dubbo.application前缀，
// 就可以拿到如下配置：
// dubbo.application.name=dubbo-demo-provider-application
// dubbo.application.logger=log4j
Map<String, Object> properties = getSubProperties(environment.getPropertySources(), prefix);
// 如果没有相关的配置项，则不需要注册BeanDefinition
if (CollectionUtils.isEmpty(properties)) {
if (log.isDebugEnabled()) {
log.debug(...);
}
return;
}
// 根据配置项生成beanNames，为什么会有多个？
// 普通情况一个dubbo.application前缀对应一个ApplicationConfig类型的Bean
// 特殊情况下（配置两种协议），比如dubbo.protocols对应了：
// dubbo.protocols.p1.name=dubbo
// dubbo.protocols.p1.port=20880
// dubbo.protocols.p1.host=0.0.0.0
// dubbo.protocols.p2.name=http
// dubbo.protocols.p2.port=8082
// dubbo.protocols.p2.host=0.0.0.0
// 那么就需要对应两个ProtocolConfig类型的Bean，那么就需要两个beanName:p1和p2
// 这里就是multiple为true或false的区别，名字的区别，根据multiple用来判断是否从配置项中获取beanName
// 如果multiple为false，则看有没有配置id属性，如果没有配置则自动生成一个beanName.
Set<String> beanNames = multiple ? resolveMultipleBeanNames(properties) : Collections.singleton(resolveSingleBeanName(properties, configClass, registry));
for (String beanName : beanNames) {
// 为每个beanName,注册一个空的BeanDefinition，方法2
registerDubboConfigBean(beanName, configClass, registry);
// 为每个bean注册一个DubboConfigBindingBeanPostProcessor的Bean后置处理器，方法3
//这里存在的问题就是对应每一种配置都会产生对应的BeanPostProcessor，最多好像也就是10种左右
//但其实一个就可以做的任务，拓展成多个貌似不太合理，结合处理逻辑都是同一套就很尴尬
registerDubboConfigBindingBeanPostProcessor(prefix, beanName, multiple, registry);
}
// 注册一个NamePropertyDefaultValueDubboConfigBeanCustomizer的bean
registerDubboConfigBeanCustomizers(registry);
}
//方法2，为对应的配置生成一个beanDefinition，并注入到容器
private void registerDubboConfigBean(String beanName, Class<? extends AbstractConfig> configClass,BeanDefinitionRegistry registry) {
BeanDefinitionBuilder builder = rootBeanDefinition(configClass);
AbstractBeanDefinition beanDefinition = builder.getBeanDefinition();
registry.registerBeanDefinition(beanName, beanDefinition); // ApplicatinoConfig对象
if (log.isInfoEnabled()) {
log.info("...); //日志记录
}
}
//方法3
private void registerDubboConfigBindingBeanPostProcessor(String prefix, String beanName, boolean multiple,BeanDefinitionRegistry registry) {
// 注册一个DubboConfigBindingBeanPostProcessor的Bean
// 每个XxConfig的Bean对应一个DubboConfigBindingBeanPostProcessor的Bean
// 比如，一个ApplicationConfig对应一个DubboConfigBindingBeanPostProcessor，
// 一个ProtocolConfig也会对应一个DubboConfigBindingBeanPostProcessor
// 在构造DubboConfigBindingBeanPostProcessor的时候会指定构造方法的值，这样就可以区别开来了
Class<?> processorClass = DubboConfigBindingBeanPostProcessor.class;
BeanDefinitionBuilder builder = rootBeanDefinition(processorClass);
// 真实的前缀，比如dubbo.registries.r2
String actualPrefix = multiple ? normalizePrefix(prefix) + beanName : prefix;
// 添加两个构造方法参数值，所以会调用DubboConfigBindingBeanPostProcessor的两个参数的构造方法
builder.addConstructorArgValue(actualPrefix).addConstructorArgValue(beanName);
AbstractBeanDefinition beanDefinition = builder.getBeanDefinition();
beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
registerWithGeneratedName(beanDefinition, registry);
if (log.isInfoEnabled()) {
log.info(...);
}
}
private void registerDubboConfigBeanCustomizers(BeanDefinitionRegistry registry) {
registerInfrastructureBean(registry, BEAN_NAME, NamePropertyDefaultValueDubboConfigBeanCustomizer.class);
}
@Override
public void setEnvironment(Environment environment) {
Assert.isInstanceOf(ConfigurableEnvironment.class, environment);
this.environment = (ConfigurableEnvironment) environment;
}
private Set<String> resolveMultipleBeanNames(Map<String, Object> properties) {
Set<String> beanNames = new LinkedHashSet<String>();
// 比如dubbo.protocols.p1.name=dubbo的propertyName为p1.name
for (String propertyName : properties.keySet()) {
// propertyName为p1.name
int index = propertyName.indexOf(".");
if (index > 0) {
// 截取beanName名字为p1
String beanName = propertyName.substring(0, index);
beanNames.add(beanName);
}
}
return beanNames;
}
private String resolveSingleBeanName(Map<String, Object> properties, Class<? extends AbstractConfig> configClass,BeanDefinitionRegistry registry) {
// 配置了dubbo.application.id=appl，那么appl就是beanName
String beanName = (String) properties.get("id");
// 如果beanName为null，则会进入if分支，由spring自动生成一个beanName,比如org.apache.dubbo.config.ApplicationConfig#0
if (!StringUtils.hasText(beanName)) {
BeanDefinitionBuilder builder = rootBeanDefinition(configClass);
beanName = BeanDefinitionReaderUtils.generateBeanName(builder.getRawBeanDefinition(), registry);
}
return beanName;
}
}
6）单个DubboConfigBindingBeanPostProcessor的展示（删减掉部分不怎么用到的）
public class DubboConfigBindingBeanPostProcessor implements BeanPostProcessor, ApplicationContextAware, InitializingBean, BeanDefinitionRegistryPostProcessor {
private final String prefix;
private final String beanName;
private DubboConfigBinder dubboConfigBinder;
....
private List<DubboConfigBeanCustomizer> configBeanCustomizers = Collections.emptyList();
....
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
// 每个XxConfig对应一个BeanPostProcessor，所以每个DubboConfigBindingBeanPostProcessor只处理对应的beanName
if (this.beanName.equals(beanName) && bean instanceof AbstractConfig) {
AbstractConfig dubboConfig = (AbstractConfig) bean;
// 从properties文件中获取值，并设置到dubboConfig对象中
bind(prefix, dubboConfig);
// 设置dubboConfig对象的name属性，设置为beanName
customize(beanName, dubboConfig);
}
return bean;
}
private void bind(String prefix, AbstractConfig dubboConfig) {
dubboConfigBinder.bind(prefix, dubboConfig);
if (log.isInfoEnabled()) {
log.info(...);
}
}
private void customize(String beanName, AbstractConfig dubboConfig) {
for (DubboConfigBeanCustomizer customizer : configBeanCustomizers) {
customizer.customize(beanName, dubboConfig);
}
}
...
@Override
public void afterPropertiesSet() throws Exception {
initDubboConfigBinder(); // 创建DefaultDubboConfigBinder
initConfigBeanCustomizers();
}
private void initDubboConfigBinder() {
if (dubboConfigBinder == null) {
try {
// 先从Spring容器中获取DubboConfigBinder，默认获取不到
dubboConfigBinder = applicationContext.getBean(DubboConfigBinder.class);
} catch (BeansException ignored) {
if (log.isDebugEnabled()) {
log.debug("DubboConfigBinder Bean can't be found in ApplicationContext.");
}
// Use Default implementation
// 生成一个默认的
dubboConfigBinder = createDubboConfigBinder(applicationContext.getEnvironment());
}
}
dubboConfigBinder.setIgnoreUnknownFields(ignoreUnknownFields);
dubboConfigBinder.setIgnoreInvalidFields(ignoreInvalidFields);
}
private void initConfigBeanCustomizers() {
// 得到之前创建了的NamePropertyDefaultValueDubboConfigBeanCustomizer
Collection<DubboConfigBeanCustomizer> configBeanCustomizers = beansOfTypeIncludingAncestors(applicationContext, DubboConfigBeanCustomizer.class).values();
this.configBeanCustomizers = new ArrayList<>(configBeanCustomizers);
AnnotationAwareOrderComparator.sort(this.configBeanCustomizers);
}
...
}
【3】注解@DubboComponentScan
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(DubboComponentScanRegistrar.class)
public @interface DubboComponentScan {
String[] value() default {};
String[] basePackages() default {};
Class<?>[] basePackageClasses() default {};
}
1）导入的DubboComponentScanRegistrar类做了什么
/又是利用了实现了ImportBeanDefinitionRegistrar接口，在实例化该类会调用其registerBeanDefinitions方法；
public class DubboComponentScanRegistrar implements ImportBeanDefinitionRegistrar {
@Override
public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
//执行DubboComponentScanRegistrar
// 拿到DubboComponentScan注解所定义的包路径，扫描该package下的类，识别这些类上
Set<String> packagesToScan = getPackagesToScan(importingClassMetadata);
// 注册ServiceAnnotationBeanPostProcessor一个Bean
// 实现了BeanDefinitionRegistryPostProcessor接口，所以在Spring启动时会调用postProcessBeanDefinitionRegistry方法
// 该方法会进行扫描，扫描@Service注解了的类，然后生成BeanDefinition（会生成两个，一个普通的bean，一个ServiceBean），后续的Spring周期中会生成Bean
// 在ServiceBean中会监听ContextRefreshedEvent事件，一旦Spring启动完后，就会进行服务导出
registerServiceAnnotationBeanPostProcessor(packagesToScan, registry);
// 注册ReferenceAnnotationBeanPostProcessor
// 实现了AnnotationInjectedBeanPostProcessor接口，继而实现了InstantiationAwareBeanPostProcessorAdapter接口
// 所以Spring在启动时，在对属性进行注入时会调用AnnotationInjectedBeanPostProcessor接口中的postProcessPropertyValues方法
// 在这个过程中会按照@Refrence注解的信息去生成一个RefrenceBean对象
registerReferenceAnnotationBeanPostProcessor(registry);
}
//核心方法1，注册一个对@Service注解处理的 BeanDefinitionRegistryPostProcessor
private void registerServiceAnnotationBeanPostProcessor(Set<String> packagesToScan, BeanDefinitionRegistry registry) {
// 生成一个RootBeanDefinition，对应的beanClass为ServiceAnnotationBeanPostProcessor.class
BeanDefinitionBuilder builder = rootBeanDefinition(ServiceAnnotationBeanPostProcessor.class);
// 将包路径作为在构造ServiceAnnotationBeanPostProcessor时调用构造方法时的传入参数
builder.addConstructorArgValue(packagesToScan);
builder.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
AbstractBeanDefinition beanDefinition = builder.getBeanDefinition();
BeanDefinitionReaderUtils.registerWithGeneratedName(beanDefinition, registry);
}
//核心方法2，注册一个对属性赋值处理的AnnotationInjectedBeanPostProcessor且带有ApplicationListener事件监听功能
private void registerReferenceAnnotationBeanPostProcessor(BeanDefinitionRegistry registry) {
// Register @Reference Annotation Bean Processor
// 注册一个ReferenceAnnotationBeanPostProcessor做为bean，ReferenceAnnotationBeanPostProcessor是一个BeanPostProcessor
BeanRegistrar.registerInfrastructureBean(registry,ReferenceAnnotationBeanPostProcessor.BEAN_NAME, ReferenceAnnotationBeanPostProcessor.class);
}
private Set<String> getPackagesToScan(AnnotationMetadata metadata) {
AnnotationAttributes attributes = AnnotationAttributes.fromMap(
metadata.getAnnotationAttributes(DubboComponentScan.class.getName()));
String[] basePackages = attributes.getStringArray("basePackages");
Class<?>[] basePackageClasses = attributes.getClassArray("basePackageClasses");
String[] value = attributes.getStringArray("value");
// Appends value array attributes
Set<String> packagesToScan = new LinkedHashSet<String>(Arrays.asList(value));
packagesToScan.addAll(Arrays.asList(basePackages));
for (Class<?> basePackageClass : basePackageClasses) {
packagesToScan.add(ClassUtils.getPackageName(basePackageClass));
}
if (packagesToScan.isEmpty()) {
return Collections.singleton(ClassUtils.getPackageName(metadata.getClassName()));
}
return packagesToScan;
}
}
【4】扫描@Service注解，并且进行处理
汇总说明：实际上便是通过处理器扫描@Service注解的类，生成两个Bean【类对应的普通Bean，与Dubbo中要用到的ServiceBean】
其中ServiceBean，是先根据注解上的信息填充对应的属性，后采用环境变量中获取配置的属性，来完成属性填充。
public class ServiceAnnotationBeanPostProcessor implements BeanDefinitionRegistryPostProcessor, EnvironmentAware,ResourceLoaderAware, BeanClassLoaderAware {
...
//核心方法1
@Override
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
Set<String> resolvedPackagesToScan = resolvePackagesToScan(packagesToScan);
if (!CollectionUtils.isEmpty(resolvedPackagesToScan)) {
// 扫描包，进行Bean注册，核心方法2调用
registerServiceBeans(resolvedPackagesToScan, registry);
} else {
if (logger.isWarnEnabled()) {
logger.warn("packagesToScan is empty , ServiceBean registry will be ignored!");
}
}
}
//核心方法2
private void registerServiceBeans(Set<String> packagesToScan, BeanDefinitionRegistry registry) {
DubboClassPathBeanDefinitionScanner scanner = new DubboClassPathBeanDefinitionScanner(registry, environment, resourceLoader);
BeanNameGenerator beanNameGenerator = resolveBeanNameGenerator(registry);
scanner.setBeanNameGenerator(beanNameGenerator);
// 扫描被Service注解标注的类
scanner.addIncludeFilter(new AnnotationTypeFilter(Service.class));
scanner.addIncludeFilter(new AnnotationTypeFilter(com.alibaba.dubbo.config.annotation.Service.class));
for (String packageToScan : packagesToScan) {
// Registers @Service Bean first
// 扫描Dubbo自定义的@Service注解
scanner.scan(packageToScan);
// 查找被@Service注解的类的BeanDefinition（无论这个类有没有被@ComponentScan注解标注了）
Set<BeanDefinitionHolder> beanDefinitionHolders = findServiceBeanDefinitionHolders(scanner, packageToScan, registry, beanNameGenerator);
if (!CollectionUtils.isEmpty(beanDefinitionHolders)) {
// 扫描到BeanDefinition开始处理它，核心方法3的调用
for (BeanDefinitionHolder beanDefinitionHolder : beanDefinitionHolders) {
registerServiceBean(beanDefinitionHolder, registry, scanner);
}
if (logger.isInfoEnabled()) { logger.info(b...); }
} else {
if (logger.isWarnEnabled()) { logger.warn(...); }
}
}
}
//核心方法3
private void registerServiceBean(BeanDefinitionHolder beanDefinitionHolder, BeanDefinitionRegistry registry, DubboClassPathBeanDefinitionScanner scanner) {
// 处理扫描到的每一个BeanDefinition
// 1. 得到@Service注解上所配置的参数
// 2. 根据每一个BeanDefinition会再额外的生成一个ServiceBean
// 3. 对于每一个被@Service注解的类（服务的实现类），会生成两个Bean，一个服务实现类对应的Bean（普通Bean，和@Component一样），一个ServiceBean（Dubbo中要用到的Bean，因为在ServiceBean中包括了很的Config）
// 具体的服务实现类
Class<?> beanClass = resolveClass(beanDefinitionHolder);
// @Service可以对服务进行各种配置
Annotation service = findServiceAnnotation(beanClass);
AnnotationAttributes serviceAnnotationAttributes = getAnnotationAttributes(service, false, false);
// 服务实现类对应的接口
Class<?> interfaceClass = resolveServiceInterfaceClass(serviceAnnotationAttributes, beanClass);
// 服务实现类对应的bean的名字，比如：demoServiceImpl
String annotatedServiceBeanName = beanDefinitionHolder.getBeanName();
// 生成一个ServiceBean，核心方法4的调用
AbstractBeanDefinition serviceBeanDefinition = buildServiceBeanDefinition(service, serviceAnnotationAttributes, interfaceClass, annotatedServiceBeanName);
// ServiceBean Bean name ServiceBean表示服务，我们要使用一个服务应该拿ServiceBean
String beanName = generateServiceBeanName(serviceAnnotationAttributes, interfaceClass);
if (scanner.checkCandidate(beanName, serviceBeanDefinition)) { // check duplicated candidate bean
// 把ServiceBean注册进去，对应的beanName为ServiceBean:org.apache.dubbo.demo.DemoService
registry.registerBeanDefinition(beanName, serviceBeanDefinition);
if (logger.isInfoEnabled()) { logger.info(..); }
} else {
if (logger.isWarnEnabled()) { logger.warn(...); }
}
}
...
//核心方法4
private AbstractBeanDefinition buildServiceBeanDefinition(Annotation serviceAnnotation,AnnotationAttributes serviceAnnotationAttributes,Class<?> interfaceClass,String annotatedServiceBeanName) {
// 生成一个ServiceBean对应的BeanDefinition
BeanDefinitionBuilder builder = rootBeanDefinition(ServiceBean.class);
AbstractBeanDefinition beanDefinition = builder.getBeanDefinition();
MutablePropertyValues propertyValues = beanDefinition.getPropertyValues();
String[] ignoreAttributeNames = of("provider", "monitor", "application", "module", "registry", "protocol",
"interface", "interfaceName", "parameters");
// 把serviceAnnotation中的参数值赋值给ServiceBean的属性
// 如：@Service(test = "test")
propertyValues.addPropertyValues(new AnnotationPropertyValuesAdapter(serviceAnnotation, environment, ignoreAttributeNames));
// References "ref" property to annotated-@Service Bean
// 如：@Service(protocol = "P1")，这种就是要根据对应的值找到对应的P1的config对象里面的值
// ref属性赋值为另外一个bean, 对应的就是被@Service注解的服务实现类对应的bean
addPropertyReference(builder, "ref", annotatedServiceBeanName);
// Set interface
builder.addPropertyValue("interface", interfaceClass.getName());
// Convert parameters into map
builder.addPropertyValue("parameters", convertParameters(serviceAnnotationAttributes.getStringArray("parameters")));
// 配置了methods属性，则给ServiceBean对应的methods属性赋值
// Add methods parameters
List<MethodConfig> methodConfigs = convertMethodConfigs(serviceAnnotationAttributes.get("methods"));
if (!methodConfigs.isEmpty()) {
builder.addPropertyValue("methods", methodConfigs);
}
/**
* Add {@link org.apache.dubbo.config.ProviderConfig} Bean reference
*/
String providerConfigBeanName = serviceAnnotationAttributes.getString("provider");
if (StringUtils.hasText(providerConfigBeanName)) {
addPropertyReference(builder, "provider", providerConfigBeanName);
}
/**
* Add {@link org.apache.dubbo.config.MonitorConfig} Bean reference
*/
String monitorConfigBeanName = serviceAnnotationAttributes.getString("monitor");
if (StringUtils.hasText(monitorConfigBeanName)) {
addPropertyReference(builder, "monitor", monitorConfigBeanName);
}
/**
* Add {@link org.apache.dubbo.config.ApplicationConfig} Bean reference
*/
String applicationConfigBeanName = serviceAnnotationAttributes.getString("application");
if (StringUtils.hasText(applicationConfigBeanName)) {
addPropertyReference(builder, "application", applicationConfigBeanName);
}
/**
* Add {@link org.apache.dubbo.config.ModuleConfig} Bean reference
*/
String moduleConfigBeanName = serviceAnnotationAttributes.getString("module");
if (StringUtils.hasText(moduleConfigBeanName)) {
addPropertyReference(builder, "module", moduleConfigBeanName);
}
/**
* Add {@link org.apache.dubbo.config.RegistryConfig} Bean reference
* 获取注解上配置的注册中心的beanName
*/
String[] registryConfigBeanNames = serviceAnnotationAttributes.getStringArray("registry");
List<RuntimeBeanReference> registryRuntimeBeanReferences = toRuntimeBeanReferences(registryConfigBeanNames);
if (!registryRuntimeBeanReferences.isEmpty()) {
builder.addPropertyValue("registries", registryRuntimeBeanReferences);
}
/**
* Add {@link org.apache.dubbo.config.ProtocolConfig} Bean reference
*/
String[] protocolConfigBeanNames = serviceAnnotationAttributes.getStringArray("protocol");
List<RuntimeBeanReference> protocolRuntimeBeanReferences = toRuntimeBeanReferences(protocolConfigBeanNames);
if (!protocolRuntimeBeanReferences.isEmpty()) {
builder.addPropertyValue("protocols", protocolRuntimeBeanReferences);
}
return builder.getBeanDefinition();
}
....
}
【5】扫描@Reference注解，并且进行处理
1）ReferenceAnnotationBeanPostProcessor类会被调用是基于继承关系
//class ReferenceAnnotationBeanPostProcessor extends AnnotationInjectedBeanPostProcessor
//abstract class AnnotationInjectedBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter
//InstantiationAwareBeanPostProcessorAdapter类便是属性注入时候会调用的
//调用AnnotationInjectedBeanPostProcessor抽象类的postProcessPropertyValues方法
@Override
public PropertyValues postProcessPropertyValues(
PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName) throws BeanCreationException {
// 寻找需要注入的属性（被@Reference标注的Field）
InjectionMetadata metadata = findInjectionMetadata(beanName, bean.getClass(), pvs);
try {
metadata.inject(bean, beanName, pvs);
} catch (BeanCreationException ex) {
throw ex;
} catch (Throwable ex) {
throw new BeanCreationException(beanName, "Injection of @" + getAnnotationType().getSimpleName()
+ " dependencies is failed", ex);
}
return pvs;
}
//最终走回到ReferenceAnnotationBeanPostProcessor类的doGetInjectedBean方法
2）ReferenceAnnotationBeanPostProcessor中的方法
public class ReferenceAnnotationBeanPostProcessor extends AnnotationInjectedBeanPostProcessor implements ApplicationContextAware, ApplicationListener {
...
// 该方法得到的对象会赋值给@ReferenceBean注解的属性
@Override
protected Object doGetInjectedBean(AnnotationAttributes attributes, Object bean, String beanName, Class<?> injectedType,InjectionMetadata.InjectedElement injectedElement) throws Exception {
// 得到引入服务的beanName
// attributes里存的是@Reference注解中的所配置的属性与值
// injectedType表示引入的是哪个服务接口
// referencedBeanName的值为 ServiceBean:org.apache.dubbo.demo.DemoService 表示得到该服务Bean的beanName
// referencedBeanName表示 我现在要引用的这个服务，它导出时对应的ServiceBean的beanName是什么，可以用来判断现在我引用的这个服务是不是我自己导出的
String referencedBeanName = buildReferencedBeanName(attributes, injectedType);
// @Reference(methods=[Lorg.apache.dubbo.config.annotation.Method;@39b43d60) org.apache.dubbo.demo.DemoService
// 我要生成一个RefrenceBean，对应的beanName， 根据@Reference注解来标识不同
String referenceBeanName = getReferenceBeanName(attributes, injectedType);
// 生成一个ReferenceBean对象，方法1
ReferenceBean referenceBean = buildReferenceBeanIfAbsent(referenceBeanName, attributes, injectedType);
// 把referenceBean添加到Spring容器中去，方法2
registerReferenceBean(referencedBeanName, referenceBean, attributes, injectedType);
cacheInjectedReferenceBean(referenceBean, injectedElement);
// 创建一个代理对象，Service中的属性被注入的就是这个代理对象
// 内部会调用referenceBean.get(); ，核心方法1
return getOrCreateProxy(referencedBeanName, referenceBeanName, referenceBean, injectedType);
}
//方法1
private ReferenceBean buildReferenceBeanIfAbsent(String referenceBeanName, AnnotationAttributes attributes, Class<?> referencedType) throws Exception {
ReferenceBean<?> referenceBean = referenceBeanCache.get(referenceBeanName);
if (referenceBean == null) {
// 生成了一个ReferenceBean对象，attributes是@Reference注解的参数值
ReferenceBeanBuilder beanBuilder = ReferenceBeanBuilder
.create(attributes, applicationContext)
.interfaceClass(referencedType);
referenceBean = beanBuilder.build();
referenceBeanCache.put(referenceBeanName, referenceBean);
} else if (!referencedType.isAssignableFrom(referenceBean.getInterfaceClass())) {
throw new IllegalArgumentException(...);
}
return referenceBean;
}
//方法2
private void registerReferenceBean(String referencedBeanName, ReferenceBean referenceBean, AnnotationAttributes attributes, Class<?> interfaceClass) {
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
// @Reference(parameters=[Ljava.lang.String;@72ef8d15) org.apache.dubbo.demo.DemoService
// ReferenceBean的beanName，注意这个beanName，它是直接取的@Reference的全信息
// 所以，就算引用的是同一个服务，如果@Reference注解上的信息不同，那么就会生成不同的ReferenceBean
String beanName = getReferenceBeanName(attributes, interfaceClass);
// 要引入的服务就是本地提供的一个服务
if (existsServiceBean(referencedBeanName)) { // If @Service bean is local one
/**
* Get the @Service's BeanDefinition from {@link BeanFactory}
* Refer to {@link ServiceAnnotationBeanPostProcessor#buildServiceBeanDefinition}
*/
AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) beanFactory.getBeanDefinition(referencedBeanName);
RuntimeBeanReference runtimeBeanReference = (RuntimeBeanReference) beanDefinition.getPropertyValues().get("ref"); // ServiceBean --- ref
// The name of bean annotated @Service
String serviceBeanName = runtimeBeanReference.getBeanName();
// register Alias rather than a new bean name, in order to reduce duplicated beans
// 如果是本地提供的一个服务，那么就@Reference(parameters=[Ljava.lang.String;@72ef8d15) org.apache.dubbo.demo.DemoService
// 的别名是demoService，不需要是ServiceBean的名字
beanFactory.registerAlias(serviceBeanName, beanName);
} else { // Remote @Service Bean
if (!beanFactory.containsBean(beanName)) {
beanFactory.registerSingleton(beanName, referenceBean);
}
}
}
//核心方法1
//这里面其实有点绕，因为@Reference其实也相当于做了@Autowired的工作
//能在本地找到，如果不代理的话其实相当于@Autowired注入属性（不会走Dubbo的逻辑），所以包装成代理，让它也走Dubbo的逻辑
private Object getOrCreateProxy(String referencedBeanName, String referenceBeanName, ReferenceBean referenceBean, Class<?> serviceInterfaceType) {
//这个其实是判断本地有没有
if (existsServiceBean(referencedBeanName)) { // If the local @Service Bean exists, build a proxy of ReferenceBean
//进行代理，让它走Dubbo的逻辑
return newProxyInstance(getClassLoader(), new Class[]{serviceInterfaceType}, wrapInvocationHandler(referenceBeanName, referenceBean));
} else { // ReferenceBean should be initialized and get immediately
// 重点，服务引入的地方
return referenceBean.get();
}
}
...
}
【6】图示：
Dubbo服务导出
【0】服务导出要做的几件事情：
1. 确定服务的参数 2. 确定服务支持的协议 3. 构造服务最终的URL 4. 将服务URL注册到注册中心去 5. 根据服务支持的不同协议，启动不同的Server，用来接收和处理请求 6. 因为Dubbo支持动态配置服务参数，所以服务导出时还需要绑定一个监听器Listener来监听服务的参数是否有修改，如果发现有修改，则需要重新进行导出
【1】核心点记录
ServiceBean的两种暴露服务的方法 1.利用InitializingBean接口，调用export()方法（没有监听器的情况下才行） 2.利用监听ContextRefreshedEvent事件达到服务暴露动态代理生成 Invoker 包装成 wrapperInvoker
RegistryProtocol进行注册 DubboProtocol对 Invoker 进行导出，返回一个Exporter
ExchangeServer
【2】ServiceBean是怎么进程服务导出的
//1是利用InitializingBean接口，调用export()方法【主要是调用父类的export()方法和发布ServiceBeanExportedEvent事件】
//2是利用监听ContextRefreshedEvent事件达到服务暴露
public class ServiceBean<T> extends ServiceConfig<T> implements InitializingBean, DisposableBean, ApplicationContextAware, ApplicationListener<ContextRefreshedEvent>, BeanNameAware, ApplicationEventPublisherAware {
....
@Override
public void setApplicationContext(ApplicationContext applicationContext) {
this.applicationContext = applicationContext;
// 如果某一个Service是通过Spring暴露的，
// 那么当需要获取该服务时就要从Spring容器中进行获取，
// 也就是从applicationContext中获取，所以需要把applicationContext添加到SpringExtensionFactory中去
SpringExtensionFactory.addApplicationContext(applicationContext);
// 一定要有这一步，不然ServiceBean将接收不到ContextRefreshedEvent事件
supportedApplicationListener = addApplicationListener(applicationContext, this);
}
//当接收到监听ContextRefreshedEvent事件时候
@Override
public void onApplicationEvent(ContextRefreshedEvent event) {
// 当前服务没有被导出并且没有卸载，才导出服务
if (!isExported() && !isUnexported()) {
if (logger.isInfoEnabled()) {
logger.info("The service ready on spring started. service: " + getInterface());
}
// 服务导出（服务注册）
export();
}
}
@Override
@SuppressWarnings({"unchecked", "deprecation"})
public void afterPropertiesSet() throws Exception {
// 如果@Service中没有配置provider
if (getProvider() == null) {
// 就从Spring容器中找ProviderConfig类型的Bean
Map<String, ProviderConfig> providerConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProviderConfig.class, false, false);
if (providerConfigMap != null && providerConfigMap.size() > 0) {
// 从Spring容器中找ProtocolConfig类型的Bean
Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false);
// 如果存在ProtocolConfig存在，并且存在多个ProviderConfig
if (CollectionUtils.isEmptyMap(protocolConfigMap) && providerConfigMap.size() > 1) { // backward compatibility
// 如果找到多个，取第一个default等于true的ProviderConfig
List<ProviderConfig> providerConfigs = new ArrayList<ProviderConfig>();
for (ProviderConfig config : providerConfigMap.values()) {
if (config.isDefault() != null && config.isDefault()) {
providerConfigs.add(config);
}
}
if (!providerConfigs.isEmpty()) {
setProviders(providerConfigs);
}
} else {
ProviderConfig providerConfig = null;
for (ProviderConfig config : providerConfigMap.values()) {
if (config.isDefault() == null || config.isDefault()) {
if (providerConfig != null) {
throw new IllegalStateException(...);
}
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 (applicationConfig != null) {
throw new IllegalStateException(...);
}
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()) {
if (moduleConfig != null) {
throw new IllegalStateException(...);
}
moduleConfig = config;
}
}
if (moduleConfig != null) {
setModule(moduleConfig);
}
}
}
// registryIds代码能看到，但是没找到在哪里能配置
if (StringUtils.isEmpty(getRegistryIds())) {
if (getApplication() != null && StringUtils.isNotEmpty(getApplication().getRegistryIds())) {
setRegistryIds(getApplication().getRegistryIds());
}
if (getProvider() != null && StringUtils.isNotEmpty(getProvider().getRegistryIds())) {
setRegistryIds(getProvider().getRegistryIds());
}
}
if ((CollectionUtils.isEmpty(getRegistries())) && (getProvider() == null || CollectionUtils.isEmpty(getProvider().getRegistries())) && (getApplication() == null || CollectionUtils.isEmpty(getApplication().getRegistries()))) {
Map<String, RegistryConfig> registryConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, RegistryConfig.class, false, false);
if (CollectionUtils.isNotEmptyMap(registryConfigMap)) {
List<RegistryConfig> registryConfigs = new ArrayList<>();
if (StringUtils.isNotEmpty(registryIds)) {
Arrays.stream(COMMA_SPLIT_PATTERN.split(registryIds)).forEach(id -> {
if (registryConfigMap.containsKey(id)) {
registryConfigs.add(registryConfigMap.get(id));
}
});
}
if (registryConfigs.isEmpty()) {
for (RegistryConfig config : registryConfigMap.values()) {
if (StringUtils.isEmpty(registryIds) && (config.isDefault() == null || config.isDefault().booleanValue())) {
registryConfigs.add(config);
}
}
}
if (!registryConfigs.isEmpty()) {
super.setRegistries(registryConfigs);
}
}
}
if (getMetadataReportConfig() == null) {
Map<String, MetadataReportConfig> metadataReportConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, MetadataReportConfig.class, false, false);
if (metadataReportConfigMap != null && metadataReportConfigMap.size() == 1) {
super.setMetadataReportConfig(metadataReportConfigMap.values().iterator().next());
} else if (metadataReportConfigMap != null && metadataReportConfigMap.size() > 1) {
throw new IllegalStateException("Multiple MetadataReport configs: " + metadataReportConfigMap);
}
}
if (getConfigCenter() == null) {
Map<String, ConfigCenterConfig> configenterMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ConfigCenterConfig.class, false, false);
if (configenterMap != null && configenterMap.size() == 1) {
super.setConfigCenter(configenterMap.values().iterator().next());
} else if (configenterMap != null && configenterMap.size() > 1) {
throw new IllegalStateException("Multiple ConfigCenter found:" + configenterMap);
}
}
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()) {
if (monitorConfig != null) {
throw new IllegalStateException("Duplicate monitor configs: " + monitorConfig + " and " + config);
}
monitorConfig = config;
}
}
if (monitorConfig != null) {
setMonitor(monitorConfig);
}
}
}
if (getMetrics() == null) {
Map<String, MetricsConfig> metricsConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, MetricsConfig.class, false, false);
if (metricsConfigMap != null && metricsConfigMap.size() > 0) {
MetricsConfig metricsConfig = null;
for (MetricsConfig config : metricsConfigMap.values()) {
if (metricsConfig != null) {
throw new IllegalStateException("Duplicate metrics configs: " + metricsConfig + " and " + config);
}
metricsConfig = config;
}
if (metricsConfig != null) {
setMetrics(metricsConfig);
}
}
}
// protocolIds也没看到在哪里配置
if (StringUtils.isEmpty(getProtocolIds())) {
if (getProvider() != null && StringUtils.isNotEmpty(getProvider().getProtocolIds())) {
setProtocolIds(getProvider().getProtocolIds());
}
}
if (CollectionUtils.isEmpty(getProtocols())
&& (getProvider() == null || CollectionUtils.isEmpty(getProvider().getProtocols()))) {
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>();
if (StringUtils.isNotEmpty(getProtocolIds())) {
Arrays.stream(COMMA_SPLIT_PATTERN.split(getProtocolIds()))
.forEach(id -> {
if (protocolConfigMap.containsKey(id)) {
protocolConfigs.add(protocolConfigMap.get(id));
}
});
}
if (protocolConfigs.isEmpty()) {
for (ProtocolConfig config : protocolConfigMap.values()) {
if (StringUtils.isEmpty(protocolIds)) {
protocolConfigs.add(config);
}
}
}
if (!protocolConfigs.isEmpty()) {
super.setProtocols(protocolConfigs);
}
}
}
if (StringUtils.isEmpty(getPath())) {
if (StringUtils.isNotEmpty(beanName)
&& StringUtils.isNotEmpty(getInterface())
&& beanName.startsWith(getInterface())) {
setPath(beanName);
}
}
//没有监听事件才做暴露服务
if (!supportedApplicationListener) {
export();
}
}
//服务暴露的核心方法
@Override
public void export() {
super.export();
// Publish ServiceBeanExportedEvent
publishExportEvent();
}
private void publishExportEvent() {
ServiceBeanExportedEvent exportEvent = new ServiceBeanExportedEvent(this);
applicationEventPublisher.publishEvent(exportEvent);
}
@Override
public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
this.applicationEventPublisher = applicationEventPublisher;
}
}
1）ServiceConfig类#export()方法
public synchronized void export() {
//读取配置并补全（最新最全的配置），方法1
checkAndUpdateSubConfigs();
// 检查服务是否需要导出
if (!shouldExport()) {
return;
}
// 检查是否需要延迟发布
if (shouldDelay()) {
DELAY_EXPORT_EXECUTOR.schedule(this::doExport, getDelay(), TimeUnit.MILLISECONDS);
} else {
// 导出服务，方法2
doExport();
}
}
2）方法1：ServiceConfig类#checkAndUpdateSubConfigs()方法
/**
* 1. ServiceConfig中的某些属性如果是空的，那么就从ProviderConfig、ModuleConfig、ApplicationConfig中获取
* 2. 从配置中心获取配置，包括应用配置和全局配置
* 3. 从配置中心获取Provider配置
* 4. 从配置中心获取Protocol配置
* 5. 如果ApplicationConfig为空，则构造一个ApplicationConfig
* 6. 从配置中心获取Registry配置
* 7. 更新ServiceConfig中的属性为优先级最高的配置
* 8. 更新MetadataReportConfig中的属性为优先级最高的配置
* 9. 检查当前服务是不是一个泛化服务
* 10.检查Stub和Local
* 11.检查Mock
*/
public void checkAndUpdateSubConfigs() {
// ServiceConfig中的某些属性如果是空的，那么就从ProviderConfig、ModuleConfig、ApplicationConfig中获取（之前生成的配置Bean）
completeCompoundConfigs();
// 方法1.1
// 从配置中心获取配置，包括应用配置和全局配置
// 把获取到的配置放入到Environment中的externalConfigurationMap和appExternalConfigurationMap中
// 并刷新所有的Config属性
startConfigCenter();
// 如果没有ProviderConfig对象，则创建一个
checkDefault();
// 如果没有单独的配置protocols，那么就从provider获取配置的协议，添加到的ServiceConfig中去
// 假如程序员在配置文件中配了一个dubbo协议，配置中心的全局配置或应用配置中也配置了一个协议，那么就会被添加到ServiceConfig中
checkProtocol();
checkApplication();
// if protocol is not injvm checkRegistry
// 如果protocol不是只有injvm协议，表示服务调用不是只在本机jvm里面调用，那就需要用到注册中心
// 如果protocol是injvm，表示本地调用
if (!isOnlyInJvm()) {
checkRegistry();
}
// 刷新ServiceConfig，方法1.2
this.refresh();
// 如果配了metadataReportConfig，那么就刷新配置
checkMetadataReport();
if (StringUtils.isEmpty(interfaceName)) {
throw new IllegalStateException("<dubbo:service interface=\"\" /> interface not allow null!");
}
// 当前服务对应的实现类是一个GenericService，表示没有特定的接口
if (ref instanceof GenericService) {
interfaceClass = GenericService.class;
if (StringUtils.isEmpty(generic)) {
generic = Boolean.TRUE.toString();
}
} else {
// 加载接口
try {
interfaceClass = Class.forName(interfaceName, true, Thread.currentThread()
.getContextClassLoader());
} catch (ClassNotFoundException e) {
throw new IllegalStateException(e.getMessage(), e);
}
// 刷新MethodConfig，并判断MethodConfig中对应的方法在接口中是否存在
checkInterfaceAndMethods(interfaceClass, methods);
// 实现类是不是该接口类型
checkRef();
generic = Boolean.FALSE.toString();
}
// local和stub一样，不建议使用了
if (local != null) {
// 如果本地存根为true，则存根类为interfaceName + "Local"
if (Boolean.TRUE.toString().equals(local)) {
local = interfaceName + "Local";
}
// 加载本地存根类
Class<?> localClass;
try {
localClass = ClassUtils.forNameWithThreadContextClassLoader(local);
} catch (ClassNotFoundException e) {
throw new IllegalStateException(e.getMessage(), e);
}
if (!interfaceClass.isAssignableFrom(localClass)) {
throw new IllegalStateException("The local implementation class " + localClass.getName() + " not implement interface " + interfaceName);
}
}
// 本地存根
if (stub != null) {
// 如果本地存根为true，则存根类为interfaceName + "Stub"
if (Boolean.TRUE.toString().equals(stub)) {
stub = interfaceName + "Stub";
}
Class<?> stubClass;
try {
stubClass = ClassUtils.forNameWithThreadContextClassLoader(stub);
} catch (ClassNotFoundException e) {
throw new IllegalStateException(e.getMessage(), e);
}
if (!interfaceClass.isAssignableFrom(stubClass)) {
throw new IllegalStateException("The stub implementation class " + stubClass.getName() + " not implement interface " + interfaceName);
}
}
// 检查local和stub
checkStubAndLocal(interfaceClass);
// 检查mock
checkMock(interfaceClass);
}
3）方法1.1，AbstractInterfaceConfig类#startConfigCenter()方法
void startConfigCenter() {
if (configCenter == null) {
ConfigManager.getInstance().getConfigCenter().ifPresent(cc -> this.configCenter = cc);
}
// 如果配置了ConfigCenter
if (this.configCenter != null) {
// 从其他位置获取配置中心的相关属性信息，比如配置中心地址
// TODO there may have duplicate refresh
this.configCenter.refresh();
// 属性更新后，从远程配置中心获取数据(应用配置，全局配置)
prepareEnvironment();
}
// 从配置中心取到配置数据后，刷新所有的XxConfig中的属性
ConfigManager.getInstance().refreshAll();
}
private void prepareEnvironment() {
if (configCenter.isValid()) {
if (!configCenter.checkOrUpdateInited()) {
return;
}
// 动态配置中心，管理台上的配置中心
DynamicConfiguration dynamicConfiguration = getDynamicConfiguration(configCenter.toUrl());
// 如果是zookeeper，获取的就是/dubbo/config/dubbo/dubbo.properties节点中的内容
String configContent = dynamicConfiguration.getProperties(configCenter.getConfigFile(), configCenter.getGroup());
String appGroup = application != null ? application.getName() : null;
String appConfigContent = null;
if (StringUtils.isNotEmpty(appGroup)) {
// 获取的就是/dubbo/config/dubbo-demo-consumer-application/dubbo.properties节点中的内容
// 这里有bug
appConfigContent = dynamicConfiguration.getProperties (StringUtils.isNotEmpty(configCenter.getAppConfigFile()) ? configCenter.getAppConfigFile() : configCenter.getConfigFile(), appGroup );
}
try {
Environment.getInstance().setConfigCenterFirst(configCenter.isHighestPriority());
Environment.getInstance().updateExternalConfigurationMap(parseProperties(configContent));
Environment.getInstance().updateAppExternalConfigurationMap(parseProperties(appConfigContent));
} catch (IOException e) {
throw new IllegalStateException(...);
}
}
}
4）方法1.2，AbstractInterfaceConfig类#refresh()方法
// 刷新XxConfig
// 一个XxConfig对象的属性可能是有值的，也可能是没有值的，这时需要从其他位置获取属性值,来进行属性的覆盖
// 覆盖的优先级，从大到小为系统变量->配置中心应用配置->配置中心全局配置->注解或xml中定义->dubbo.properties文件
// 以ServiceConfig为例，ServiceConfig中包括很多属性，比如timeout
// 但是在定义一个Service时，如果在注解上没有配置timeout，那么就会其他地方获取timeout的配置
// 比如可以从系统变量->配置中心应用配置->配置中心全局配置->注解或xml中定义->dubbo.properties文件
// refresh是刷新，将当前ServiceConfig上的set方法所对应的属性更新为优先级最高的值
public void refresh() {
try {
CompositeConfiguration compositeConfiguration = Environment.getInstance().getConfiguration(getPrefix(), getId());
// 表示XxConfig对象本身- AbstractConfig
Configuration config = new ConfigConfigurationAdapter(this);
//设置顺序，
if (Environment.getInstance().isConfigCenterFirst()) {
// The sequence would be: SystemConfiguration -> AppExternalConfiguration -> ExternalConfiguration -> AbstractConfig -> PropertiesConfiguration
compositeConfiguration.addConfiguration(4, config);
} else {
// The sequence would be: SystemConfiguration -> AbstractConfig -> AppExternalConfiguration -> ExternalConfiguration -> PropertiesConfiguration
compositeConfiguration.addConfiguration(2, config);
}
// loop methods, get override value and set the new value back to method
//
Method[] methods = getClass().getMethods();
for (Method method : methods) {
// 是不是setXX()方法
if (MethodUtils.isSetter(method)) {
// 获取xx配置项的value
String value = StringUtils.trim(compositeConfiguration.getString(extractPropertyName(getClass(), method)));
// isTypeMatch() is called to avoid duplicate and incorrect update, for example, we have two 'setGeneric' methods in ReferenceConfig.
if (StringUtils.isNotEmpty(value) && ClassUtils.isTypeMatch(method.getParameterTypes()[0], value)) {
method.invoke(this, ClassUtils.convertPrimitive(method.getParameterTypes()[0], value));
}
// 是不是setParameters()方法
} else if (isParametersSetter(method)) {
// 获取parameter配置项的value
String value = StringUtils.trim(compositeConfiguration.getString(extractPropertyName(getClass(), method)));
if (StringUtils.isNotEmpty(value)) {
Map<String, String> map = invokeGetParameters(getClass(), this);
map = map == null ? new HashMap<>() : map;
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