SpringIOC源码分析

1. BeanFactoryPostProcessor与BeanPostProcessor执行顺序

• 整体顺序：
• 1. BeanFactoryPostProcessor中 postProcessorBeanFactory
• 2. 实例化Bean。调用bean中的set方法设值。
• 3. BeanFactoryPostProcessor 中的 postProcessorBeforeInitializing
• 4. 初始化Bean。PostConstruct注解的方法执行 --> InitializingBean 接口的 afterPropertiesSet
• 5. BeanFactoryPostProcessor 中的 postProcessorAfterInitializing

/**
 * Created by zhaozhebin on 2018/10/14
 * <p>
 * BeanPostProcessor接口
 * （bean的初始化前后，也就是赋值阶段，即调用setter方法）
 * <p>
 * BeanFactoryPostProcessor(Bean创建之前，读取Bean的元属性，并根据自己的需求对元属性进行改变，比如将Bean的scope从singleton改变为prototype)
 * <p>
 * 1、BeanFactoryPostProcessor的执行优先级高于BeanPostProcessor
 * <p>
 * 2、BeanFactoryPostProcessor的postProcessBeanFactory()方法只会执行一次,携带了每个bean的基本信息
 */
@Configuration
@ComponentScan(value = "com.zzb.mytest.TestSpring.TestBeanPostProcessor")
public class TestBeanPostProcessor {

    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
        context.register(TestBeanPostProcessor.class);
        context.refresh();
        TestBean test = context.getBean(TestBean.class);
        test.say();
        System.out.println(test.getName());
    }


    @Service
    public class A implements BeanPostProcessor {

        /**
         * 该方法在bean实例化完毕（且已经注入完毕），在afterPropertiesSet或自定义init方法执行之前
         */
        @Override
        public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
            if (bean.getClass().equals(TestBean.class)) {
                System.out.println("before.....");
            }
            return bean;
        }
        /**
         *  在afterPropertiesSet或自定义init方法执行之后
         */
        @Override
        public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
            if (bean.getClass().equals(TestBean.class)) {
                System.out.println("after.....");
            }
            return bean;
        }
    }
}

@Component
public class TestBean implements InitializingBean {
    private String name;

    public TestBean() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void say() {
        System.out.println("zzb say");
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("do afterPropertiesSet...");
        this.name = "caoxizhaozhebin";
    }

    @PostConstruct
    public void method(){
        name="post construct";
        System.out.println("post construct");
    }
}

@Component
public class TestBeanFactoryPostProcessor implements BeanFactoryPostProcessor{
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("postProcessBeanFactory....---....");
      //  TestBeanPostProcessor.Test test=beanFactory.getBean(TestBeanPostProcessor.Test.class);
        //test.setName("qqqqqq");
        BeanDefinition definition=beanFactory.getBeanDefinition("testBean");
        MutablePropertyValues values=definition.getPropertyValues();
        values.addPropertyValue("name","caoxi");
    }
}