标签：deb hash null tcl ryu can 修改 bst 需要
一、BeanFactoryPostProcessor这个是spring容器的拓展之一，其目的是在容器初始化完成之前，通过beanFactory对上下文进行进行操作。
二、常用场景，需要对beanDefinition做处理，提供获取bean的方式。基本上涉及到的容器的加载修改，都可以操作。
三、实现方式
public class TestBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
//这里是要求必须实现的，也是我们操作的地方
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
}
}
说明：这里的ConfigurableListableBeanFactory 也就是我们初始化中用到的DefaultListableBeanFactory
四、源码实现
1）在容器初始化的refresh中实现的方式是
//beanFactory的后置操作
this.invokeBeanFactoryPostProcessors(beanFactory);
2）invokeBeanFactoryPostProcessors
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
Set processedBeans = new HashSet();
Iterator var9;
ArrayList orderedPostProcessors;
//这里判断是否是DefaultListableBeanFactory的接口
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry)beanFactory;
List regularPostProcessors = new LinkedList();
List registryPostProcessors = new LinkedList();
//获取初始化是否就存在BeanFactoryPostProcessor的类型
Iterator var7 = this.getBeanFactoryPostProcessors().iterator();
BeanDefinitionRegistryPostProcessor postProcessor;
while(var7.hasNext()) {
BeanFactoryPostProcessor postProcessor = (BeanFactoryPostProcessor)var7.next();
//如果是BeanDefinitionRegistryPostProcessor注册类型的调用postProcessBeanDefinitionRegistry
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
postProcessor = (BeanDefinitionRegistryPostProcessor)postProcessor;
//主要是注册bean的方式，这个是BeanFactoryPostProcessor的子接口
postProcessor.postProcessBeanDefinitionRegistry(registry);
registryPostProcessors.add(postProcessor);
} else {
//不是BeanDefinitionRegistryPostProcessor类型的直接放入regularPostProcessors
regularPostProcessors.add(postProcessor);
}
}
//这里通过getBeansOfType方式加载继承BeanDefinitionRegistryPostProcessor方式的所有bean
Map beanMap = beanFactory.getBeansOfType(BeanDefinitionRegistryPostProcessor.class, true, false);
orderedPostProcessors = new ArrayList(beanMap.values());
//根据@Order进行排序
OrderComparator.sort(orderedPostProcessors);
var9 = orderedPostProcessors.iterator();
while(var9.hasNext()) {
postProcessor = (BeanDefinitionRegistryPostProcessor)var9.next();
//执行相关操作
postProcessor.postProcessBeanDefinitionRegistry(registry);
}
//这里执行对应的后置beanFactory后置操作
this.invokeBeanFactoryPostProcessors(registryPostProcessors, beanFactory);
this.invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
this.invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
//添加BeanDefinitionRegistryPostProcessor的bean
processedBeans.addAll((Collection)beanMap.keySet());
} else {
//如果不是DefaultListableBeanFactory(当然还有其他类型)
this.invokeBeanFactoryPostProcessors(this.getBeanFactoryPostProcessors(), beanFactory);
}
//这里才是重点，主要是实现BeanFactoryPostProcessor的接口bean
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
List priorityOrderedPostProcessors = new ArrayList();
//这里分两种，一中是有序的一中是无序的
List orderedPostProcessorNames = new ArrayList();
List nonOrderedPostProcessorNames = new ArrayList();
String[] var10 = postProcessorNames;
int var19 = postProcessorNames.length;
for(int var18 = 0; var18 var18) {
String ppName = var10[var18];
if (!processedBeans.contains(ppName)) {
//匹配对应排序
if (this.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add((BeanFactoryPostProcessor)beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
} else if (this.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
} else {
//一般使用无序的操作
nonOrderedPostProcessorNames.add(ppName);
}
}
}
//有序的操作
OrderComparator.sort(priorityOrderedPostProcessors);
this.invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
orderedPostProcessors = new ArrayList();
var9 = orderedPostProcessorNames.iterator();
while(var9.hasNext()) {
String postProcessorName = (String)var9.next();
orderedPostProcessors.add((BeanFactoryPostProcessor)this.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
OrderComparator.sort(orderedPostProcessors);
this.invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
//无序的BeanFactoryPostProcessor操作
List nonOrderedPostProcessors = new ArrayList();
Iterator var23 = nonOrderedPostProcessorNames.iterator();
while(var23.hasNext()) {
String postProcessorName = (String)var23.next();
nonOrderedPostProcessors.add((BeanFactoryPostProcessor)this.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
this.invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
}
//执行BeanFactoryPostProcessor结构中的postProcessBeanFactory方法
private void invokeBeanFactoryPostProcessors(Collection extends BeanFactoryPostProcessor> postProcessors, ConfigurableListableBeanFactory beanFactory) {
Iterator var4 = postProcessors.iterator();
while(var4.hasNext()) {
BeanFactoryPostProcessor postProcessor = (BeanFactoryPostProcessor)var4.next();
//实现BeanFactoryPostProcessor的方法可以通过beanFactory进行操作
postProcessor.postProcessBeanFactory(beanFactory);
}
}
3）getBeanNamesForType
public String[] getBeanNamesForType(Class type, boolean includeNonSingletons, boolean allowEagerInit) {
List result = new ArrayList();
//获取beanName
String[] beanDefinitionNames = this.getBeanDefinitionNames();
String[] var9 = beanDefinitionNames;
int var8 = beanDefinitionNames.length;
for(int var7 = 0; var7 var7) {
String beanName = var9[var7];
//检查是否是别名
if (!this.isAlias(beanName)) {
try {
//获取BeanDefinition
RootBeanDefinition mbd = this.getMergedLocalBeanDefinition(beanName);
if (!mbd.isAbstract() && (allowEagerInit || (mbd.hasBeanClass() || !mbd.isLazyInit() || this.allowEagerClassLoading) && !this.requiresEagerInitForType(mbd.getFactoryBeanName()))) {
boolean isFactoryBean = this.isFactoryBean(beanName, mbd);
boolean matchFound = (allowEagerInit || !isFactoryBean || this.containsSingleton(beanName)) && (includeNonSingletons || this.isSingleton(beanName)) && this.isTypeMatch(beanName, type);
if (!matchFound && isFactoryBean) {
beanName = "&" + beanName;
//查看是否匹配
matchFound = (includeNonSingletons || mbd.isSingleton()) && this.isTypeMatch(beanName, type);
}
if (matchFound) {
result.add(beanName);
}
}
} catch (CannotLoadBeanClassException var13) {
if (allowEagerInit) {
throw var13;
}
if (this.logger.isDebugEnabled()) {
this.logger.debug("Ignoring bean class loading failure for bean ‘" + beanName + "‘", var13);
}
this.onSuppressedException(var13);
} catch (BeanDefinitionStoreException var14) {
if (allowEagerInit) {
throw var14;
}
if (this.logger.isDebugEnabled()) {
this.logger.debug("Ignoring unresolvable metadata in bean definition ‘" + beanName + "‘", var14);
}
this.onSuppressedException(var14);
}
}
}
//查看单例中是否存在
String[] singletonNames = this.getSingletonNames();
String[] var18 = singletonNames;
int var17 = singletonNames.length;
for(var8 = 0; var8 var8) {
String beanName = var18[var8];
if (!this.containsBeanDefinition(beanName)) {
if (this.isFactoryBean(beanName)) {
//查看是否匹配
if ((includeNonSingletons || this.isSingleton(beanName)) && this.isTypeMatch(beanName, type)) {
result.add(beanName);
continue;
}
beanName = "&" + beanName;
}
if (this.isTypeMatch(beanName, type)) {
result.add(beanName);
}
}
}
return StringUtils.toStringArray(result);
}
public String[] getBeanDefinitionNames() {
Map var1 = this.beanDefinitionMap;
//这里的锁，主要是方式新的bean加入进来
synchronized(this.beanDefinitionMap) {
return this.frozenBeanDefinitionNames != null ? this.frozenBeanDefinitionNames : StringUtils.toStringArray(this.beanDefinitionNames);
}
}
public boolean isTypeMatch(String name, Class targetType) throws NoSuchBeanDefinitionException {
String beanName = this.transformedBeanName(name);
Class typeToMatch = targetType != null ? targetType : Object.class;
//在单例中获取
Object beanInstance = this.getSingleton(beanName, false);
if (beanInstance != null) {
if (beanInstance instanceof FactoryBean) {
if (!BeanFactoryUtils.isFactoryDereference(name)) {
Class type = this.getTypeForFactoryBean((FactoryBean)beanInstance);
return type != null && typeToMatch.isAssignableFrom(type);
} else {
return typeToMatch.isAssignableFrom(beanInstance.getClass());
}
} else {
return !BeanFactoryUtils.isFactoryDereference(name) && typeToMatch.isAssignableFrom(beanInstance.getClass());
}
} else if (this.containsSingleton(beanName) && !this.containsBeanDefinition(beanName)) {
return false;
} else {
BeanFactory parentBeanFactory = this.getParentBeanFactory();
if (parentBeanFactory != null && !this.containsBeanDefinition(beanName)) {
return parentBeanFactory.isTypeMatch(this.originalBeanName(name), targetType);
} else {
//通过BeanDefinitionHolder方式判定
RootBeanDefinition mbd = this.getMergedLocalBeanDefinition(beanName);
BeanDefinitionHolder dbd = mbd.getDecoratedDefinition();
Class type;
if (dbd != null && !BeanFactoryUtils.isFactoryDereference(name)) {
RootBeanDefinition tbd = this.getMergedBeanDefinition(dbd.getBeanName(), dbd.getBeanDefinition(), mbd);
type = this.predictBeanType(dbd.getBeanName(), tbd, FactoryBean.class, typeToMatch);
if (type != null && !FactoryBean.class.isAssignableFrom(type)) {
//判断是否匹配
return typeToMatch.isAssignableFrom(type);
}
}
Class beanClass = this.predictBeanType(beanName, mbd, FactoryBean.class, typeToMatch);
if (beanClass == null) {
return false;
} else if (FactoryBean.class.isAssignableFrom(beanClass)) {
if (!BeanFactoryUtils.isFactoryDereference(name)) {
//通过bean类型进行判断
type = this.getTypeForFactoryBean(beanName, mbd);
return type != null && typeToMatch.isAssignableFrom(type);
} else {
return typeToMatch.isAssignableFrom(beanClass);
}
} else {
return !BeanFactoryUtils.isFactoryDereference(name) && typeToMatch.isAssignableFrom(beanClass);
}
}
}
}
五、说明(源码部分解说，比较简单。主要是实现过程不复杂，主要是其中的操作，太多了)
1、BeanFactoryPostProcessor的后置beanFactroy处理主要是在refresh的this.invokeBeanFactoryPostProcessors(beanFactory);上面完成的。
2、在invokeBeanFactoryPostProcessors中是处理的BeanFactoryPostProcessor的子接口BeanDefinitionRegistryPostProcessor的postProcessBeanDefinitionRegistry方法。
3、在BeanFactoryPostProcessor的使用过程中使用了2中排序方式PriorityOrder和Order的方式
4、通过beanFactory的getBeanNamesForType方法，匹配实现BeanFactoryPostProcessor的bean.
5、在getBeanNamesForType中isTypeMatch是主要匹配类型的关键。
6、总体来说就是xml解析完成过后，进行的后置beanFactory的处理。
spring源码-BeanFactoryPostProcessor-3.2
标签：deb hash null tcl ryu can 修改 bst 需要
原文地址：https://www.cnblogs.com/ll409546297/p/9675776.html