对属性资源的扩展，还没弄明白
@Override
protected void initPropertySources(){
}BeanDefinitionRegistryPostProcessor
实现对BeanDefinition的处理，实现的功能
- 注册BeanDefinition
- 移除BeanDefinition
- 是否包含BeanDefinition
- 获取所有的BeanDefinition的名称
- 修改BeanDefinition
BeanFactoryPostProcessor
主要是对BeanFactory的修改，不能注册BeanDefinition
ImportBeanDefinitionRegistrar
- 只能通过@Import来引入ImportBeanDefinitionRegistrar的实现类
- 通过注解的方式注册不了ImportBeanDefinitionRegistrar的实现类
- 会自动调用下面个方法
// 回调次方法
default void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry,BeanNameGenerator importBeanNameGenerator) {
registerBeanDefinitions(importingClassMetadata, registry);
}
default void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {}InstantiationAwareBeanPostProcessor
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
System.out.println(beanName);
System.out.println("初始化之前");
return bean;
}
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
System.out.println(beanName);
System.out.println("初始化之后");
return bean;
}
@Override
public Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException {
System.out.println(beanName);
System.out.println("实例化之前");
return null;
}
@Override
public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
System.out.println(beanName);
System.out.println("实例化之后");
return false;
}- FactoryBean
FactoryBean的接口可以改变真是的Bean对象
@Component
public class MyFactoryBean implements FactoryBean {
@Override
public Object getObject() throws Exception {
return new Object();
}
@Override
public Class<?> getObjectType() {
return Object.class;
}
}- BeanNameAware
- ApplicationContextAware
- BeanFactoryAware
- BeanClassLoaderAware
package com.bysj.extend;
// 利用这些接口可以在创建bean时获取一些bean的信息
@Component
public class MyBeanTend implements BeanNameAware, ApplicationContextAware, BeanFactoryAware,BeanClassLoaderAware {
// BeanNameAware
@Override
public void setBeanName(String name) {
System.out.println(name);
}
// ApplicationContextAware
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
System.out.println(applicationContext);
}
// BeanFactoryAware
@Override
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
System.out.println(beanFactory);
}
// BeanClassLoaderAware
@Override
public void setBeanClassLoader(ClassLoader classLoader) {
System.out.println(classLoader);
}
}- DisposableBean
- InitializingBean
// DisposableBean的方法
@Override
public void destroy() throws Exception {
System.out.println("销毁中-------------");
}
// InitializingBean的方法
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("afterPropertiesSet");
}@PostConstruct
@Value @Autowired
在AutowiredxxxBeanFactoryPostPocessor
ComponentScanAnnotationParser
通过启动类的包名获取扫描路径，把controller和service的bean扫描到容器里面
Set<String> basePackages = new LinkedHashSet<>();
if (basePackages.isEmpty()) {
basePackages.add(ClassUtils.getPackageName(declaringClass));
}
return scanner.doScan(StringUtils.toStringArray(basePackages));- 获取扫描的包路径
- 引入MapperScannerRegistrar这个类
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
@Documented
@Import({MapperScannerRegistrar.class})
@Repeatable(MapperScans.class)
public @interface MapperScan {
String[] value() default {};
String[] basePackages() default {};
Class<?>[] basePackageClasses() default {};
Class<? extends BeanNameGenerator> nameGenerator() default BeanNameGenerator.class;
Class<? extends Annotation> annotationClass() default Annotation.class;
Class<?> markerInterface() default Class.class;
String sqlSessionTemplateRef() default "";
String sqlSessionFactoryRef() default "";
Class<? extends MapperFactoryBean> factoryBean() default MapperFactoryBean.class;
String lazyInitialization() default "";
}通过这个类注册MapperScannerConfigurer为BeanDefinition
BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(MapperScannerConfigurer.class);
/**
给builder对象添加各种属性的操作，这些代码已经省略
*/
registry.registerBeanDefinition(beanName, builder.getBeanDefinition());- 保存着扫描Mapper的路径
public class MapperScannerConfigurer implements BeanDefinitionRegistryPostProcessor, InitializingBean, ApplicationContextAware, BeanNameAware {
private String basePackage; //Mapper的路径
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry){
ClassPathMapperScanner scanner = new ClassPathMapperScanner(registry);
scanner.registerFilters();
//ClassPathMapperScanner的方法
scanner.scan(StringUtils.tokenizeToStringArray(this.basePackage, ",; \t\n"));
}
}- ClassPathMapperScanner extends ClassPathBeanDefinitionScanner
// 这是ClassPathBeanDefinitionScanner的scan方法
public int scan(String... basePackages) {
int beanCountAtScanStart = this.registry.getBeanDefinitionCount();
this.doScan(basePackages);
if (this.includeAnnotationConfig) {
AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);
}
return this.registry.getBeanDefinitionCount() - beanCountAtScanStart;
}
// ClassPathMapperScanner的方法
public Set<BeanDefinitionHolder> doScan(String... basePackages) {
Set<BeanDefinitionHolder> beanDefinitions = super.doScan(basePackages);
if (beanDefinitions.isEmpty()) {
// 省略......
} else {
// 这个方法会替换成动态Mybatis的FactoryBean
this.processBeanDefinitions(beanDefinitions);
}
return beanDefinitions;
}
private void processBeanDefinitions(Set<BeanDefinitionHolder> beanDefinitions) {
GenericBeanDefinition definition;
for(Iterator var3 = beanDefinitions.iterator(); var3.hasNext(); definition.setLazyInit(this.lazyInitialization)) {
BeanDefinitionHolder holder = (BeanDefinitionHolder)var3.next();
definition = (GenericBeanDefinition)holder.getBeanDefinition();
String beanClassName = definition.getBeanClassName();
// 设置成为MapperFactoryBean
definition.setBeanClass(this.mapperFactoryBeanClass);
definition.getPropertyValues().add("addToConfig", this.addToConfig);
}