Spring 包扫描

Myth丶恋晨 2022-06-12 07:36 175阅读 0赞

这是入口

public class BeanScannerConfigurer implements BeanFactoryPostProcessor, ApplicationListener<ContextRefreshedEvent> {
        private Scanner scanner;
    
        public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
            scanner = new Scanner((BeanDefinitionRegistry) beanFactory);
        }
    
        @Override
        public void onApplicationEvent(ContextRefreshedEvent event) {
            if (event.getApplicationContext().getParent() == null) {
                scanner.setResourceLoader(event.getApplicationContext());
                scanner.scan("com.hieip");
            }
        }
    }

这是扫描器主体

public final class Scanner extends ClassPathBeanDefinitionScanner {
        public Scanner(BeanDefinitionRegistry registry) {
            super(registry);
        }
    
        public void registerDefaultFilters() {
            this.addIncludeFilter(new AnnotationTypeFilter(Component.class));
        }
    
        public Set<BeanDefinitionHolder> doScan(String... basePackages) {
            Assert.notEmpty(basePackages, "At least one base package must be specified");
            Set<BeanDefinitionHolder> beanDefinitions = new LinkedHashSet<BeanDefinitionHolder>();
            for (String basePackage : basePackages) {
                Set<BeanDefinition> candidates = findCandidateComponents(basePackage);
                for (BeanDefinition candidate : candidates) {
    //                candidate.hasAttribute()
                    //todo 实现是否属于该注解 Class<?> clazz = null;
                    String beanClassName = candidate.getBeanClassName();
                    try {
                        clazz = Class.forName(beanClassName);//反射生成对象
                    } catch (ClassNotFoundException e) {
                        e.printStackTrace();
                    }
                    Method[] methods = clazz.getMethods();//获取方法
                    for (Method method: methods
                         ) {
                        Annotation annotation = method.getAnnotation(AuthAnnotation.class);//获取权限注解
                        if(null!=annotation){
      //判断是否有注解
                            String beanName = beanClassName.substring(beanClassName.lastIndexOf(".")+1);
                            beanDefinitions.add(new BeanDefinitionHolder(candidate,beanName));//生成返回对象
                        }
                    }
                }
            }
            return beanDefinitions;
        }
    
        public boolean isCandidateComponent(AnnotatedBeanDefinition beanDefinition) {
            return super.isCandidateComponent(beanDefinition) && beanDefinition.getMetadata()
                    .hasAnnotation(Service.class.getName());
        }
    }