注：源码版本是2.7.4.1
在之前spring学习中，我们知道，spring容器启动的时候，会先生成BeanDefinition，这个步骤是在obtainFreshBeanFactory（我们这里是用注解讲的，所以有点不一样）中。dubbo在项目中，配置了META-INF/spring.handler，内容如下：
http\://dubbo.apache.org/schema/dubbo=org.apache.dubbo.config.spring.schema.DubboNamespaceHandler
http\://code.alibabatech.com/schema/dubbo=org.apache.dubbo.config.spring.schema.DubboNamespaceHandlerdubbo的BeanDefinitionParser的加载在DubboNamespaceHandler类中，通过DubboBeanDefinitionParser解析BeanDefinition。
public void init() {
registerBeanDefinitionParser("application", new DubboBeanDefinitionParser(ApplicationConfig.class, true));
registerBeanDefinitionParser("module", new DubboBeanDefinitionParser(ModuleConfig.class, true));
registerBeanDefinitionParser("registry", new DubboBeanDefinitionParser(RegistryConfig.class, true));
registerBeanDefinitionParser("config-center", new DubboBeanDefinitionParser(ConfigCenterBean.class, true));
registerBeanDefinitionParser("metadata-report", new DubboBeanDefinitionParser(MetadataReportConfig.class, true));
registerBeanDefinitionParser("monitor", new DubboBeanDefinitionParser(MonitorConfig.class, true));
registerBeanDefinitionParser("metrics", new DubboBeanDefinitionParser(MetricsConfig.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 AnnotationBeanDefinitionParser());
}具体的解析在DubboBeanDefinitionParser的parse()中。
private static BeanDefinition parse(Element element, ParserContext parserContext, Class beanClass, boolean required) {
RootBeanDefinition beanDefinition = new RootBeanDefinition();
beanDefinition.setBeanClass(beanClass);
beanDefinition.setLazyInit(false);
String id = element.getAttribute("id");
// 没有id，通过name、ProtocolConfig、interface、beanClass赋值给id
if (StringUtils.isEmpty(id) && required) {
// 获取名称
String generatedBeanName = element.getAttribute("name");
if (StringUtils.isEmpty(generatedBeanName)) {
// 如果是ProtocolConfig，名称定义为dubbo
if (ProtocolConfig.class.equals(beanClass)) {
generatedBeanName = "dubbo";
} else {
// 如果不是ProtocolConfig，名称定义为interface的值
generatedBeanName = element.getAttribute("interface");
}
}
// 如果不是ProtocolConfig且没有interface属性，用类名
if (StringUtils.isEmpty(generatedBeanName)) {
generatedBeanName = beanClass.getName();
}
id = generatedBeanName;
int counter = 2;
while (parserContext.getRegistry().containsBeanDefinition(id)) {
id = generatedBeanName + (counter++);
}
}
// 注册beanDefinition并增加id的属性值
if (StringUtils.isNotEmpty(id)) {
if (parserContext.getRegistry().containsBeanDefinition(id)) {
throw new IllegalStateException("Duplicate spring bean id " + id);
}
parserContext.getRegistry().registerBeanDefinition(id, beanDefinition);
beanDefinition.getPropertyValues().addPropertyValue("id", id);
}
// 给具有protocol属性的赋值
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)) {
// 如果有class属性，则创建新的BeanDefinition，并重置ref
String className = element.getAttribute("class");
if (StringUtils.isNotEmpty(className)) {
RootBeanDefinition classDefinition = new RootBeanDefinition();
classDefinition.setBeanClass(ReflectUtils.forName(className));
classDefinition.setLazyInit(false);
// 解析子属性
parseProperties(element.getChildNodes(), classDefinition);
// 重置ref
beanDefinition.getPropertyValues().addPropertyValue("ref", new BeanDefinitionHolder(classDefinition, id + "Impl"));
}
} else if (ProviderConfig.class.equals(beanClass)) {
// 解析Provider子节点的service标签，并给service赋值provider的属性
parseNested(element, parserContext, ServiceBean.class, true, "service", "provider", id, beanDefinition);
} else if (ConsumerConfig.class.equals(beanClass)) {
// 解析Consumer子节点的reference标签，并给reference赋值consumer的属性
parseNested(element, parserContext, ReferenceBean.class, false, "reference", "consumer", id, beanDefinition);
}
Set props = new HashSet<>();
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) {
Class type = setter.getParameterTypes()[0];
String beanProperty = name.substring(3, 4).toLowerCase() + name.substring(4);
String property = StringUtils.camelToSplitName(beanProperty, "-");
props.add(property);
// check the setter/getter whether match
Method getter = null;
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) {
// ignore, there is no need any log here since some class implement the interface: EnvironmentAware,
// ApplicationAware, etc. They only have setter method, otherwise will cause the error log during application start up.
}
}
if (getter == null
|| !Modifier.isPublic(getter.getModifiers())
|| !type.equals(getter.getReturnType())) {
continue;
}
if ("parameters".equals(property)) {
// 解析参数dubbo:parameters属性
parameters = parseParameters(element.getChildNodes(), beanDefinition);
} else if ("methods".equals(property)) {
// 解析方法dubbo:method属性
parseMethods(id, element.getChildNodes(), beanDefinition, parserContext);
} else if ("arguments".equals(property)) {
// 解析方法参数arguments属性
parseArguments(id, element.getChildNodes(), beanDefinition, parserContext);
} else {
String value = element.getAttribute(property);
if (value != null) {
value = value.trim();
if (value.length() > 0) {
// 点对点的情况
if ("registry".equals(property) && RegistryConfig.NO_AVAILABLE.equalsIgnoreCase(value)) {
RegistryConfig registryConfig = new RegistryConfig();
registryConfig.setAddress(RegistryConfig.NO_AVAILABLE);
beanDefinition.getPropertyValues().addPropertyValue(beanProperty, registryConfig);
} else if ("provider".equals(property) || "registry".equals(property) || ("protocol".equals(property) && AbstractServiceConfig.class.isAssignableFrom(beanClass))) {
/**
* For 'provider' 'protocol' 'registry', keep literal value (should be id/name) and set the value to 'registryIds' 'providerIds' protocolIds'
* The following process should make sure each id refers to the corresponding instance, here's how to find the instance for different use cases:
* 1. Spring, check existing bean by id, see{@link ServiceBean#afterPropertiesSet()}; then try to use id to find configs defined in remote Config Center
* 2. API, directly use id to find configs defined in remote Config Center; if all config instances are defined locally, please use {@link ServiceConfig#setRegistries(List)}
*/
beanDefinition.getPropertyValues().addPropertyValue(beanProperty + "Ids", value);
} else {
Object reference;
if (isPrimitive(type)) {
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)) {
// backward compatibility for the default value in old version's xsd
value = null;
}
reference = value;
} else if (ONRETURN.equals(property) || ONTHROW.equals(property) || ONINVOKE.equals(property)) {
int index = value.lastIndexOf(".");
String ref = value.substring(0, index);
String method = value.substring(index + 1);
reference = new RuntimeBeanReference(ref);
beanDefinition.getPropertyValues().addPropertyValue(property + METHOD, method);
} else {
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: ");
}
}
reference = new RuntimeBeanReference(value);
}
beanDefinition.getPropertyValues().addPropertyValue(beanProperty, reference);
}
}
}
}
}
}
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;
} 以上就把ApplicationConfig、ModuleConfig、RegistryConfig等对应的BeanDefinition注册到spring中。