Spring的Bean生命周期，11 张高清流程图及代码，深度解析

protectedObject resolveBeforeInstantiation(String beanName, RootBeanDefinition mbd) {
Object bean = null;
//条件1
if(!Boolean.FALSE.equals(mbd.beforeInstantiationResolved)) {
//条件2跟条件3
if(!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
Class<?> targetType = determineTargetType(beanName, mbd);
if(targetType != null) {
//调用实现的postProcessBeforeInstantiation方法
                    bean = applyBeanPostProcessorsBeforeInstantiation(targetType, beanName);
if(bean != null) {
//调用实现的postProcessAfterInitialization方法
                        bean = applyBeanPostProcessorsAfterInitialization(bean, beanName);
}
}
}
//不满足2或者3的时候就会设置为false
            mbd.beforeInstantiationResolved = (bean != null);
}
return bean;
}

protectedBeanWrapper createBeanInstance(String beanName, RootBeanDefinition mbd, @NullableObject[] args) {
//步骤1
Class<?> beanClass = resolveBeanClass(mbd, beanName);

if(beanClass != null&& !Modifier.isPublic(beanClass.getModifiers()) && !mbd.isNonPublicAccessAllowed()) {
thrownewBeanCreationException(mbd.getResourceDescription(), beanName,
"Bean class isn't public, and non-public access not allowed: "+ beanClass.getName());
}
//步骤2
Supplier<?> instanceSupplier = mbd.getInstanceSupplier();
if(instanceSupplier != null) {
return obtainFromSupplier(instanceSupplier, beanName);
}
//步骤3
if(mbd.getFactoryMethodName() != null) {
return instantiateUsingFactoryMethod(beanName, mbd, args);
}


boolean resolved = false;
boolean autowireNecessary = false;
if(args == null) {
synchronized(mbd.constructorArgumentLock) {
if(mbd.resolvedConstructorOrFactoryMethod != null) {
                    resolved = true;
                    autowireNecessary = mbd.constructorArgumentsResolved;
}
}
}
//步骤4.1
if(resolved) {

if(autowireNecessary) {
return autowireConstructor(beanName, mbd, null, null);
}
else{

return instantiateBean(beanName, mbd);
}
}

//步骤4.2
Constructor<?>[] ctors = determineConstructorsFromBeanPostProcessors(beanClass, beanName);
if(ctors != null|| mbd.getResolvedAutowireMode() == AUTOWIRE_CONSTRUCTOR ||
                mbd.hasConstructorArgumentValues() || !ObjectUtils.isEmpty(args)) {
return autowireConstructor(beanName, mbd, ctors, args);
}

//步骤5
        ctors = mbd.getPreferredConstructors();
if(ctors != null) {
return autowireConstructor(beanName, mbd, ctors, null);
}


return instantiateBean(beanName, mbd);
}

protectedvoid populateBean(String beanName, RootBeanDefinition mbd, @NullableBeanWrapper bw) {
if(bw == null) {
if(mbd.hasPropertyValues()) {
thrownewBeanCreationException(
                        mbd.getResourceDescription(), beanName, "Cannot apply property values to null instance");
}
else{
// Skip property population phase for null instance.
return;
}
}


boolean continueWithPropertyPopulation = true;
//步骤1
if(!mbd.isSynthetic() && hasInstantiationAwareBeanPostProcessors()) {
for(BeanPostProcessor bp : getBeanPostProcessors()) {
if(bp instanceofInstantiationAwareBeanPostProcessor) {
InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
if(!ibp.postProcessAfterInstantiation(bw.getWrappedInstance(), beanName)) {
                        continueWithPropertyPopulation = false;
break;
}
}
}
}

if(!continueWithPropertyPopulation) {
return;
}
//步骤2--------------------
PropertyValues pvs = (mbd.hasPropertyValues() ? mbd.getPropertyValues() : null);

int resolvedAutowireMode = mbd.getResolvedAutowireMode();
if(resolvedAutowireMode == AUTOWIRE_BY_NAME || resolvedAutowireMode == AUTOWIRE_BY_TYPE) {
MutablePropertyValues newPvs = newMutablePropertyValues(pvs);
// Add property values based on autowire by name if applicable.
if(resolvedAutowireMode == AUTOWIRE_BY_NAME) {
                autowireByName(beanName, mbd, bw, newPvs);
}
// Add property values based on autowire by type if applicable.
if(resolvedAutowireMode == AUTOWIRE_BY_TYPE) {
                autowireByType(beanName, mbd, bw, newPvs);
}
            pvs = newPvs;
}

boolean hasInstAwareBpps = hasInstantiationAwareBeanPostProcessors();
boolean needsDepCheck = (mbd.getDependencyCheck() != AbstractBeanDefinition.DEPENDENCY_CHECK_NONE);

PropertyDescriptor[] filteredPds = null;
//步骤3
if(hasInstAwareBpps) {
if(pvs == null) {
                pvs = mbd.getPropertyValues();
}
for(BeanPostProcessor bp : getBeanPostProcessors()) {
if(bp instanceofInstantiationAwareBeanPostProcessor) {
InstantiationAwareBeanPostProcessor ibp = (InstantiationAwareBeanPostProcessor) bp;
PropertyValues pvsToUse = ibp.postProcessProperties(pvs, bw.getWrappedInstance(), beanName);
if(pvsToUse == null) {
if(filteredPds == null) {
                            filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
}
                        pvsToUse = ibp.postProcessPropertyValues(pvs, filteredPds, bw.getWrappedInstance(), beanName);
if(pvsToUse == null) {
return;
}
}
                    pvs = pvsToUse;
}
}
}
if(needsDepCheck) {
if(filteredPds == null) {
                filteredPds = filterPropertyDescriptorsForDependencyCheck(bw, mbd.allowCaching);
}
            checkDependencies(beanName, mbd, filteredPds, pvs);
}
//步骤4
if(pvs != null) {
            applyPropertyValues(beanName, mbd, bw, pvs);
}
}

protectedvoid prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
.......
        beanFactory.addBeanPostProcessor(newApplicationContextAwareProcessor(this));
.......

publicObject postProcessBeforeInitialization(Object bean, String beanName) throwsBeansException{
if(!(bean instanceofEnvironmentAware|| bean instanceofEmbeddedValueResolverAware||
                bean instanceofResourceLoaderAware|| bean instanceofApplicationEventPublisherAware||
                bean instanceofMessageSourceAware|| bean instanceofApplicationContextAware)){
return bean;
}

AccessControlContext acc = null;

if(System.getSecurityManager() != null) {
            acc = this.applicationContext.getBeanFactory().getAccessControlContext();
}

if(acc != null) {
AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
                invokeAwareInterfaces(bean);
returnnull;
}, acc);
}
else{
            invokeAwareInterfaces(bean);
}

return bean;
}

protectedvoid registerDisposableBeanIfNecessary(String beanName, Object bean, RootBeanDefinition mbd) {
......
                registerDisposableBean(beanName,
newDisposableBeanAdapter(bean, beanName, mbd, getBeanPostProcessors(), acc));
......
}

publicDisposableBeanAdapter(Object bean, String beanName, RootBeanDefinition beanDefinition,
List<BeanPostProcessor> postProcessors, @NullableAccessControlContext acc) {
.......
String destroyMethodName = inferDestroyMethodIfNecessary(bean, beanDefinition);
if(destroyMethodName != null&& !(this.invokeDisposableBean && "destroy".equals(destroyMethodName)) &&
!beanDefinition.isExternallyManagedDestroyMethod(destroyMethodName)) {
......
this.destroyMethod = destroyMethod;
}
this.beanPostProcessors = filterPostProcessors(postProcessors, bean);
}

publicvoid destroyBean(Object existingBean) {
newDisposableBeanAdapter(existingBean, getBeanPostProcessors(), getAccessControlContext()).destroy();
}

publicDisposableBeanAdapter(Object bean, List<BeanPostProcessor> postProcessors, AccessControlContext acc) {
Assert.notNull(bean, "Disposable bean must not be null");
this.bean = bean;
this.beanName = bean.getClass().getName();
//根据传入的bean是否实现了`DisposableBean`接口来设置`invokeDisposableBean`变量
this.invokeDisposableBean = (this.bean instanceofDisposableBean);
this.nonPublicAccessAllowed = true;
this.acc = acc;
this.beanPostProcessors = filterPostProcessors(postProcessors, bean);
}

publicvoid destroy() {
......
//根据invokeDisposableBean决定是否调用destroy方法
if(this.invokeDisposableBean) {
if(logger.isTraceEnabled()) {
                logger.trace("Invoking destroy() on bean with name '"+ this.beanName + "'");
}
try{
if(System.getSecurityManager() != null) {
AccessController.doPrivileged((PrivilegedExceptionAction<Object>) () -> {
((DisposableBean) this.bean).destroy();
returnnull;
}, this.acc);
}
else{
((DisposableBean) this.bean).destroy();
}
}
catch(Throwable ex) {
String msg = "Invocation of destroy method failed on bean with name '"+ this.beanName + "'";
if(logger.isDebugEnabled()) {
                    logger.warn(msg, ex);
}
else{
                    logger.warn(msg + ": "+ ex);
}
}
}
......
}