package com.ysy.config;
import com.ysy.bean.Car;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
/**
* @author shanyangyang
* @date 2020/5/31
* Bean生命周期:
* Bean创建—————初始化——————销毁的过程
* 容器管理Bean的生命周期:
* 我们可以自定义初始化和销毁方法,容器在进行到对应的步骤时,会调用我们自定义的方法
* 1)指定初始化和销毁方法
* 通过@Bean指定init-method="getTestStr" destroy-method="getTestStr"
*
* 2)通过让bean实现InitializingBean接口和DisposableBean接口
*
* 3)通过使用JSR250
* 1)@PostConstruct:在Bean创建完成并且属性赋值完成,来执行初始化方法;
* 2)@PreDestroy:在容器销毁Bean之前通知进行清理工作;
*
* 4)BeanPostProcessor:bean的后置处理器
* 在Bean的初始化前后进行一些处理工作
* postProcessBeforeInitialization:在初始化调用之前
* Apply this {@code BeanPostProcessor} to the given new bean instance <i>before</i> any bean
* initialization callbacks (like InitializingBean's {@code afterPropertiesSet}
* or a custom init-method).
* postProcessAfterInitialization:在初始化之后
* Apply this {@code BeanPostProcessor} to the given new bean instance <i>after</i> any bean
* * initialization callbacks (like InitializingBean's {@code afterPropertiesSet}
* * or a custom init-method).
*
*构造(对象实例)
* 1)单实例:在容器启动的时候创建对象
* 2)多实例:在每次获取的时候创建对象
*
* BeanPostProcessor.postProcessBeforeInitialization
*初始化:
* 对象创建完成,并赋值完成,调用初始化方法。。。。
*
* BeanPostProcessor.postProcessAfterInitialization
* 销毁:
* 单实例:容器关闭的时候
* 多实例:容器不会管理这个Bean,容器不会调用销毁方法
*
* populateBean之后执行下面的方法:
* 给Bean属性赋值
*
*遍历得到容器所有的BeanPostProcessor,挨个执行BeforeInitialization,一旦返回null,跳出for循环,不会执行后面的BeanPostProcessor
* if (mbd == null || !mbd.isSynthetic()) {
* wrappedBean = applyBeanPostProcessorsBeforeInitialization(wrappedBean, beanName);
* }
*
* try {
* //执行初始化方法
* invokeInitMethods(beanName, wrappedBean, mbd);
* }
* catch (Throwable ex) {
* throw new BeanCreationException(
* (mbd != null ? mbd.getResourceDescription() : null),
* beanName, "Invocation of init method failed", ex);
* }
* if (mbd == null || !mbd.isSynthetic()) {
* wrappedBean = applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
* }
*
*
* Spring底层对BeanPostProcessor的使用,
* bean赋值,注入其他组件,@Autowired,生命周期注解功能,@Sync,等等;
*
*/
@Configuration
@ComponentScan("com.ysy.bean")
public class MainConfigOfLifeCycle {
//@Scope("prototype")
@Bean(initMethod = "init",destroyMethod = "destroy")
public Car car(){
return new Car();
}
}
后置处理器类
package com.ysy.bean;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;
/**
* 后置处理器:初始化前后进行处理
* bean the new bean instance
* beanName the name of the bean
* @author shanyangyang
* @date 2020/5/31
*/
@Component
public class MyBeanPostProccessor implements BeanPostProcessor {
@Override public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
System.out.println("postProcessBeforeInitialization......."+beanName+".....>>"+bean);
return bean;
}
@Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
System.out.println("postProcessAfterInitialization......."+beanName+".....>>"+bean);
return bean;
}
}
测试类
package com.ysy.test;
import com.ysy.config.MainConfigOfLifeCycle;
import org.junit.Test;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* @author shanyangyang
* @date 2020/5/31
*/
public class IOCTestLifeCycle {
@Test
public void test01(){
//创建IOC容器
AnnotationConfigApplicationContext context =
new AnnotationConfigApplicationContext(MainConfigOfLifeCycle.class);
System.out.println("容器创建完成。。。。");
context.getBean("car");
context.close();
}
}