1. Spring Bean实例化
1. 通过BeanName获取Class对象（resolveBeanClass(mbd, beanName);）
2. 处理lookup标签（mbdToUse.prepareMethodOverrides();）// Prepare method overrides.
3. 短路Bean的创建过程 Object bean = resolveBeforeInstantiation(beanName, mbdToUse);
// Give BeanPostProcessors a chance to return a proxy instead of the target bean instance.
Object bean = resolveBeforeInstantiation(beanName, mbdToUse);
if (bean != null) {
return bean;
}
Class targetType = determineTargetType(beanName, mbd);
if (targetType != null) {
bean = applyBeanPostProcessorsBeforeInstantiation(targetType, beanName);
if (bean != null) {
bean = applyBeanPostProcessorsAfterInitialization(bean, beanName);
}
}
protected Object applyBeanPostProcessorsBeforeInstantiation(Class beanClass, String beanName) {
for (BeanPostProcessor bp : getBeanPostProcessors()) {
if (bp instanceof InstantiationAwareBeanPostProcessor) {
InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
Object result = ibp.postProcessBeforeInstantiation(beanClass, beanName);
if (result != null) {
return result;
}
}
}
return null;
}
public Object applyBeanPostProcessorsAfterInitialization(Object existingBean, String beanName)
throws BeansException {
Object result = existingBean;
for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) {
result = beanProcessor.postProcessAfterInitialization(result, beanName);
if (result == null) {
return result;
}
}
return result;
}
4. 实例化对象（doCreateBean(beanName, mbdToUse, args);）
- 实例化对象（instanceWrapper = createBeanInstance(beanName, mbd, args)）
- 使用FactoryMethod实例化（instantiateUsingFactoryMethod(beanName, mbd, args);）
- 解析过构造参数或FactoryMethod，才使用构造参数实例化（autowireConstructor(beanName, mbd, null, null);）
- 使用策略实例化（instantiateBean(beanName, mbd);）InstantiationStrategy instantiationStrategy = new CglibSubclassingInstantiationStrategy();
- if (bd.getMethodOverrides().isEmpty()) {
- // 反射初始化
- return BeanUtils.instantiateClass(constructorToUse);
- } else {
- // Must generate CGLIB subclass.
- return instantiateWithMethodInjection(bd, beanName, owner);
- }
- 提前曝光实例（addSingletonFactory），循环依赖使用
- 填充属性（populateBean(beanName, mbd, instanceWrapper);）
- 短路属性注入 bp instanceof InstantiationAwareBeanPostProcessor / !ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)if (bp instanceof InstantiationAwareBeanPostProcessor) {
- InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
- if (!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) {
- continueWithPropertyPopulation = false;
- break;
- }
- }
- 属性注入，按照名称（autowireByName(beanName, mbd, bw, newPvs);）或类型（autowireByType(beanName, mbd, bw, newPvs);）注入
- 短路if (bp instanceof InstantiationAwareBeanPostProcessor) {
- InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
- pvs = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);
- if (pvs == null) {
- return;
- }
- }
- 应用属性（applyPropertyValues(beanName, mbd, bw, pvs);Spel表达式解析）
- 初始化Bean（initializeBean(beanName, exposedObject, mbd);）
- 执行Aware接口自动注入，包括BeanNameAware、BeanFactoryAware、BeanClassLoaderAware（invokeAwareMethods(beanName, bean);）
- 短路bean后续BeanPostProcessor执行。postProcessBeforeInitializationresult = beanProcessor.postProcessBeforeInitialization(result, beanName);
- if (result == null) {
- return result;
- }
- 执行init初始化方法（invokeInitMethods(beanName, wrappedBean, mbd);）
- ((InitializingBean) bean).afterPropertiesSet();
- invokeCustomInitMethod(beanName, bean, mbd);
- 短路bean后续BeanPostProcessor执行。wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);for (BeanPostProcessor beanProcessor : getBeanPostProcessors()) {
- result = beanProcessor.postProcessAfterInitialization(result, beanName);
- if (result == null) {
- return result;
- }
- }
5. 初始化依赖的Bean
6. Register bean as disposable.（registerDisposableBeanIfNecessary(beanName, bean, mbd);）
