registerBeanPostProcessors(beanFactory)解析

找到所有的BeanPostProcessors接口的实现类，并且注册到spring容器中，同时会真正实例化BeanPostProcessors接口的实现类

 1 流程和之前的invokeBeanFactoryPostProcessors()类似
 2 这个方法会处理开发人员自己实现的BeanPostProcessor,也会处理spring内部实现的BeanPostProcessor
 3 AutowiredAnnotationBeanPostProcessor：处理@Autowired
 4 RequiredAnnotationBeanPostProcessor：处理@Required
 5 CommonAnnotationBeanPostProcessor ：处理@RreDestory@PostConstruct @Resource
　　AnnotationAwareAspectJAutoProxyCreator:处理AOP
 6 public static void registerBeanPostProcessors(
 7             ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
 8 
 9         String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
10 
11         // Register BeanPostProcessorChecker that logs an info message when
12         // a bean is created during BeanPostProcessor instantiation, i.e. when
13         // a bean is not eligible for getting processed by all BeanPostProcessors.
14         int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
15         beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
16 
17         // Separate between BeanPostProcessors that implement PriorityOrdered,
18         // Ordered, and the rest.
19         List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
20         List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
21         List<String> orderedPostProcessorNames = new ArrayList<>();
22         List<String> nonOrderedPostProcessorNames = new ArrayList<>();
23         for (String ppName : postProcessorNames) {
24             if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
25             //这里的getBean会实例化BeanPostProcessor的实现类，其他bean(lazy!=true并且没有被使用的)的实例化在最后
26                 BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
27                 priorityOrderedPostProcessors.add(pp);
28                 if (pp instanceof MergedBeanDefinitionPostProcessor) {
29                     internalPostProcessors.add(pp);
30                 }
31             }
32             else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
33                 orderedPostProcessorNames.add(ppName);
34             }
35             else {
36                 nonOrderedPostProcessorNames.add(ppName);
37             }
38         }
39 
40         // First, register the BeanPostProcessors that implement PriorityOrdered.
41         sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
42         registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
43 
44         // Next, register the BeanPostProcessors that implement Ordered.
45         List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
46         for (String ppName : orderedPostProcessorNames) {
47             BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
48             orderedPostProcessors.add(pp);
49             if (pp instanceof MergedBeanDefinitionPostProcessor) {
50                 internalPostProcessors.add(pp);
51             }
52         }
53         sortPostProcessors(orderedPostProcessors, beanFactory);
54         registerBeanPostProcessors(beanFactory, orderedPostProcessors);
55 
56         // Now, register all regular BeanPostProcessors.
57         List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
58         for (String ppName : nonOrderedPostProcessorNames) {
59             BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
60             nonOrderedPostProcessors.add(pp);
61             if (pp instanceof MergedBeanDefinitionPostProcessor) {
62                 internalPostProcessors.add(pp);
63             }
64         }
65         registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
66 
67         // Finally, re-register all internal BeanPostProcessors.
68         sortPostProcessors(internalPostProcessors, beanFactory);
69         registerBeanPostProcessors(beanFactory, internalPostProcessors);
70 
71         // Re-register post-processor for detecting inner beans as ApplicationListeners,
72         // moving it to the end of the processor chain (for picking up proxies etc).
73         beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
74     }
75 
76     private static void sortPostProcessors(List<?> postProcessors, ConfigurableListableBeanFactory beanFactory) {
77         Comparator<Object> comparatorToUse = null;
78         if (beanFactory instanceof DefaultListableBeanFactory) {
79             comparatorToUse = ((DefaultListableBeanFactory) beanFactory).getDependencyComparator();
80         }
81         if (comparatorToUse == null) {
82             comparatorToUse = OrderComparator.INSTANCE;
83         }
84         postProcessors.sort(comparatorToUse);
85     }

 

posted @ 2021-04-30 09:13  龙之谷2019  阅读(189)  评论(0)    收藏  举报