Spring-BeanPostProcessor PostConstruct init InitializingBean 执行顺序-编程知识

Spring-BeanPostProcessor PostConstruct init InitializingBean 执行顺序

执行顺序探究

新建一个对象用于测试

@Component
public class Student implements InitializingBean {private String name;private int age;public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}/*** InitializingBean 提供的在属性设置之后执行的方法** @throws Exception*/@Overridepublic void afterPropertiesSet() throws Exception {System.out.println("====== Student afterPropertiesSet");}/*** 初始化方法用于配置 bean inti*/public void init() {System.out.println("====== afterPropertiesSet init");}/*** PostConstruct*/@PostConstructpublic void post() {System.out.println("====== Student PostConstruct");}}

新建一个TestBeanPostProcessor 实现 BeanPostProcessor

@Component
public class TestBeanPostProcessor implements BeanPostProcessor {@Overridepublic Object postProcessAfterInitialization(Object bean, String beanName) {System.out.println("======== Student postProcessAfterInitialization");return bean;}@Overridepublic Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {System.out.println("=============Student postProcessBeforeInitialization");return bean;}
}

通过注解的方式进行测试

@Test
public void test3() {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext("com.liyong.learn");
Student bean = (Student) context.getBean("student");
System.out.println(String.format("ben is name{%s} age is {%s}", bean.getName(), bean.getAge()));
}

得到的结果如下:
在这里插入图片描述
总结PostProcessBeforeInitialization -> PostConstruct -> InitializingBean -> PostProcessAfterInitialization
通过Bean.xml的方式

<bean id="student" class="com.liyong.learn.Student" init-method="init"><property name="name" value="english"></property><property name="age" value="18"></property>
</bean>
<bean id="testBeanPostProcessor" class="com.liyong.learn.TestBeanPostProcessor"></bean>

@Test
public void test () {
// 指定XML路径
String path = "beans.xml";
// 创建DefaultListableBeanFactory工厂，这也就是Spring的基本容器
DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
// 创建BeanDefinition阅读器
XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);
// 进行BeanDefinition注册流程
reader.loadBeanDefinitions(path);
beanFactory.addBeanPostProcessor((BeanPostProcessor) beanFactory.getBean("testBeanPostProcessor"));
// Bean实例创建流程
Student student = (Student) beanFactory.getBean("student");
System.out.println(String.format("bean attrs name {%s} age {%s}", student.getName(), student.getAge()));
}