1. BeanPostProcessor简介
BeanPostProcessor是Spring IOC容器给我们提供的一个扩展接口。接口声明如下:
public interface BeanPostProcessor {
//bean初始化方法调用前被调用
Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException;
//bean初始化方法调用后被调用
Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException;
}
运行顺序
===Spring IOC容器实例化Bean===
===调用BeanPostProcessor的postProcessBeforeInitialization方法===
===调用bean实例的初始化方法===
===调用BeanPostProcessor的postProcessAfterInitialization方法===
2. BeanPostProcessor实例
/**
* 后置处理器:初始化前后进行处理工作
* 将后置处理器加入到容器中
*/
@Component
public class MyBeanPostProcessor implements BeanPostProcessor {
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
// TODO Auto-generated method stub
System.out.println("postProcessBeforeInitialization..."+beanName+"=>"+bean);
return bean;
}
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
// TODO Auto-generated method stub
System.out.println("postProcessAfterInitialization..."+beanName+"=>"+bean);
return bean;
}
}
3. BeanFactoryPostProcessor简介
bean工厂的bean属性处理容器,说通俗一些就是可以管理我们的bean工厂内所有的beandefinition(未实例化)数据,可以随心所欲的修改属性。
4. BeanFactoryPostProcessor实例
@Component
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
System.out.println("MyBeanFactoryPostProcessor...postProcessBeanFactory...");
int count = beanFactory.getBeanDefinitionCount();
String[] names = beanFactory.getBeanDefinitionNames();
System.out.println("当前BeanFactory中有"+count+" 个Bean");
System.out.println(Arrays.asList(names));
}
}
区别:
注册BeanFactoryPostProcessor的实例,需要重载
void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException;
通过beanFactory可以获取bean的示例或定义等。同时可以修改bean的属性,这是和BeanPostProcessor最大的区别。
作者:xbmchina
链接:https://www.jianshu.com/p/369a54201943
来源:简书
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