Spring中BeanFactoryPostProcessor与BeanPostProcessor接口区别

    BeanFactoryPostProcessor： 这个接口是spring对外开放，实现这个接口，可以在bean定义对象没有实例化之前，读取bean定义对象配置元数据，并可以对配置元数据的一些属性修改。也就是说：BeanFactoryPostProcessor是在spring容器加载了bean的定义文件之后，在bean实例化之前执行的。在整个过程中，只调用一次这个接口的实现类。如下定义的bean ，可以对lazy-init、property的属性值进行修改。 

 

   BeanPostProcessor：是spring容器加载bean的定义文件完，且实例化了bean的定义的对象之后执行的。BeanPostProcessor接口有两个方法，一个是postProcessBeforeInitialization，一个是postProcessAfterInitialzation。postProcessBeforeInitialization方法是在对象的构成函数执行完之后，postProcessBeforeInitialization方法是定义的init-method方法之前执行的。当对象实例化完之后就是再次执行postProcessAfterInitialzation方法。 在整个过程中，每实例化一个bean的对象，都会是调到BeanPostProcessor接口的方法。

示例如下：

步骤：

1、 创建两个类，一个是Teacher,一个是student类

 2、创建两个类MyBeanFactoryPostProcessor与MyBeanPostProcessor，分别实现BeanFactoryPostProcessor与BeanPostProcessor

3、配置bean文件：bean-postprocessor.xml

4、测试类 MainDemo

 1、 创建两个类，一个是Teacher,一个是student类

package cn.lvyjx.test.postProcessor;

public class Teacher {

    public String name;
    public String phone;
    
    public Teacher(){
        System.out.println("Teacher construct!");
    }
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        System.out.println("teacher中name值的注入");
        this.name = name;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    @Override
    public String toString() {
        return "name="+name+";phone="+phone;
    }
    
    /**
     * 初始化方法 
     */
    public void init(){
        System.out.println("Teacher-init method");
    }

}

package cn.lvyjx.test.postProcessor;

public class Student {

    public String name;
    public String numberId;
    
    public Student(){
        System.out.println("Student construct!");
    }

    public String getName() {
        return name;
    }

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

    public String getNumberId() {
        return numberId;
    }

    public void setNumberId(String numberId) {
        this.numberId = numberId;
    }
    
    
}

 

     2、创建两个类，分别实现BeanFactoryPostProcessor与BeanPostProcessor

package cn.lvyjx.test.postProcessor;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;

/**
 * 对象实例化前执行
 * @author Administrator
 *
 */
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor{

    public MyBeanFactoryPostProcessor(){
        System.out.println("【BeanFactoryPostProcessor】:MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor construct!");
    }
    @Override
    public void postProcessBeanFactory(
            ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("【BeanFactoryPostProcessor】:postProcessBeanFactory method!");
        //对 teacher对象赋值/修改
       BeanDefinition bd = beanFactory.getBeanDefinition("teacher");
       bd.getPropertyValues().addPropertyValue("name", "李二");
       bd.getPropertyValues().addPropertyValue("phone", "13256487442");
    }

}

package cn.lvyjx.test.postProcessor;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

public class MyBeanPostProcessor implements BeanPostProcessor {

    public MyBeanPostProcessor(){
        System.out.println("【BeanPostProcessor】:MyBeanPostProcessor implements BeanPostProcessor construct!");
    }
    
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName)
            throws BeansException {
        System.out.println("【BeanPostProcessor-postProcessBeforeInitialization】：beanName="+beanName);
        if(bean instanceof Teacher){
            Teacher teacher = (Teacher)bean;
             System.out.println("【BeanPostProcessor-postProcessBeforeInitialization】bean.toString before："+teacher.toString());
            teacher.setName("李三");
          System.out.println("【BeanPostProcessor-postProcessBeforeInitialization】bean.toString after："+teacher.toString());
        }
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName)
            throws BeansException {
        if(bean instanceof Teacher){
            Teacher teacher = (Teacher)bean;
             System.out.println("【BeanPostProcessor-postProcessAfterInitialization】bean.toString ："+teacher.toString());
        }
        System.out.println("【BeanPostProcessor-postProcessAfterInitialization】：beanName="+beanName);
        return bean;
    }
}

 

 3、配置bean文件：bean-postprocessor.xml

 

4、测试类 MainDemo

package cn.lvyjx.test.postProcessor;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainDemo {

    public static void main(String[] args) {

        System.out.println("开始执行");
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("bean-postprocessor.xml");
        Teacher teacher = (Teacher)context.getBean("teacher");
        System.out.println(teacher.toString());

       System.out.println("结束执行");
    }
}

 

 5、运行结果

开始执行
【BeanFactoryPostProcessor】:MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor construct!
【BeanFactoryPostProcessor】:postProcessBeanFactory method!
【BeanPostProcessor】:MyBeanPostProcessor implements BeanPostProcessor construct!
Teacher construct!
teacher中name值的注入
【BeanPostProcessor-postProcessBeforeInitialization】：beanName=teacher
【BeanPostProcessor-postProcessBeforeInitialization】bean.toString before：name=李二;phone=13256487442
teacher中name值的注入
【BeanPostProcessor-postProcessBeforeInitialization】bean.toString after：name=李三;phone=13256487442
Teacher-init method
【BeanPostProcessor-postProcessAfterInitialization】bean.toString ：name=李三;phone=13256487442
【BeanPostProcessor-postProcessAfterInitialization】：beanName=teacher
Student construct!
【BeanPostProcessor-postProcessBeforeInitialization】：beanName=student
【BeanPostProcessor-postProcessAfterInitialization】：beanName=student
name=李三;phone=13256487442
结束执行