10--Spring BeanPostProcessor和Bea

2018-10-06 本文已影响55人闲来也无事

BeanPostProcessor接口：后置bean处理器，允许自定义修改新的bean实例，应用程序上下文可以在其bean定义中自动检测BeanPostProcessor类型的bean，并将它们应用于随后创建的任何bean。（例如：配置文件中注册了一个自定义BeanPostProcessor类型的bean，一个User类型的bean，应用程序上下文会在创建User实例之后对User应用BeanPostProcessor）。
BeanFactoryPostProcessor接口：后置工厂处理器，允许自定义修改应用程序上下文的bean定义，调整bean属性值。应用程序上下文可以在其bean定义中自动检测BeanFactoryPostProcessor，并在创建任何非BeanFactoryPostProcessor类型bean之前应用它们（例如：配置文件中注册了一个自定义BeanFactoryPostProcessor类型的bean，一个User类型的bean，应用程序上下文会在创建User实例之前对User应用BeanFactoryPostProcessor）。

对比	BeanFactoryPostProcessor	BeanPostProcessor
回调时间	Bean实例化完成之前	Bean实例化完成之后
是否可修改bean定义信息	是	否
是否可修改bean实例信息	否	是
是否支持排序接口	是	是
方法级别	ApplicationContext级别	ApplicationContext级别
实现方式	注册自定义BeanPostProcessor	注册自定义BeanFactoryPostProcessor，实现BeanFactoryAware接口

1. BeanPostProcessor

bean

package com.lyc.cn.v2.day02.processor.bean;

import com.lyc.cn.v2.day01.Dog;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.core.Ordered;

/**
 * 继承BeanPostProcessor接口并重写其方法
 * @author: LiYanChao
 * @create: 2018-09-06 14:56
 */
public class MyBeanPostProcessorOne implements BeanPostProcessor, Ordered {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("BeanPostProcessor第" + getOrder() + "次被调动\n");
        if (bean instanceof Dog) {
            ((Dog) bean).setName("强强");
        }
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof Dog) {
            ((Dog) bean).setAge(5);
        }
        return bean;
    }

    @Override
    public int getOrder() {
        return 1;
    }
}

package com.lyc.cn.v2.day02.processor.bean;

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

/**
 * 继承BeanPostProcessor接口并重写其方法
 * @author: LiYanChao
 * @create: 2018-09-06 14:56
 */
public class MyBeanPostProcessorTwo implements BeanPostProcessor, Ordered {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("BeanPostProcessor第" + getOrder() + "次被调动");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }

    @Override
    public int getOrder() {
        return 2;
    }
}

2. BeanFactoryPostProcessor

package com.lyc.cn.v2.day02.processor.factory;

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

public class MyBeanFactoryPostProcessorOne implements BeanFactoryPostProcessor, Ordered {

    /**
     * 修改dog的name属性值
     * 修改dog的作用域
     */
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("BeanFactoryPostProcessor第" + getOrder() + "次被调动");
        BeanDefinition bd = beanFactory.getBeanDefinition("dog");
        if (null != bd) {
            System.out.println("dog属性值:" + bd.getPropertyValues().toString());
            MutablePropertyValues pv = bd.getPropertyValues();
            if (pv.contains("name")) {
                System.out.println("修改dog的name属性值为强强");
                pv.addPropertyValue("name", "强强");
            }
            System.out.println("修改dog的作用域为prototype\n");
            bd.setScope(BeanDefinition.SCOPE_PROTOTYPE);
        }
    }

    @Override
    public int getOrder() {
        return 0;
    }
}

package com.lyc.cn.v2.day02.processor.factory;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.core.Ordered;

public class MyBeanFactoryPostProcessorTwo implements BeanFactoryPostProcessor, Ordered {

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("BeanFactoryPostProcessor第" + getOrder() + "次被调动");
    }

    @Override
    public int getOrder() {
        return 1;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd" profile="dev">

    <bean id="dog" class="com.lyc.cn.v2.day01.Dog">
        <!-- 指定构造器参数 index对应构造器中参数的位置 -->
        <!-- 也可以通过指定参数类型，指定参数名称来注入属性-->
        <constructor-arg index="0" value="小明"/>
        <constructor-arg index="1" value="3"/>
    </bean>

    <!-- =====beanPostProcessor配置begin =====-->
    <bean id="myBeanPostProcessorOne" class="com.lyc.cn.v2.day02.processor.bean.MyBeanPostProcessorOne"/>
    <bean id="myBeanPostProcessorTwo" class="com.lyc.cn.v2.day02.processor.bean.MyBeanPostProcessorTwo"/>
    <!-- =====beanPostProcessor配置end =====-->

    <!-- =====beanFactoryPostProcessor配置begin =====-->
    <!--注册第一个后置工厂处理器-->
    <bean id="myBeanFactoryPostProcessorOne" class="com.lyc.cn.v2.day02.processor.factory.MyBeanFactoryPostProcessorOne"/>
    <!--注册第二个后置工厂处理器-->
    <bean id="myBeanFactoryPostProcessorTwo" class="com.lyc.cn.v2.day02.processor.factory.MyBeanFactoryPostProcessorTwo"/>
    <!-- =====beanFactoryPostProcessor配置end =====-->

</beans>

测试

package com.lyc.cn.v2.day02;

import com.lyc.cn.v2.day01.Dog;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;

/**
 * @author: LiYanChao
 * @create: 2018-09-07 23:40
 */
public class MyTest {
    private XmlBeanFactory xmlBeanFactory;

    @Before
    public void initXmlBeanFactory() {
        System.setProperty("spring.profiles.active", "dev");
        System.out.println("\n========测试方法开始=======\n");
        xmlBeanFactory = new XmlBeanFactory(new ClassPathResource("v2/day01.xml"));
    }

    @After
    public void after() {
        System.out.println("\n========测试方法结束=======\n");
    }

    @Test
    public void test1() {
        // 测试BeanPostProcessor
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("v2/day02.xml");
        Dog dog = applicationContext.getBean("dog", Dog.class);
        dog.sayHello();
    }


    @Test
    public void test2() {
        // 测试BeanFactoryPostProcessor
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("v2/day02.xml");
        Dog dog = applicationContext.getBean("dog", Dog.class);
        dog.sayHello();
    }

}

结果
为了不影响测试结果，需要将BeanPostProcessor和BeanFactoryPostProcessor分开测试，测试test1时将test2的xml配置注释掉，反之亦然。

test1-->

========测试方法开始=======

BeanPostProcessor第1次被调动

BeanPostProcessor第2次被调动
大家好, 我叫强强, 我今年5岁了

========测试方法结束=======

test2-->

========测试方法开始=======

BeanFactoryPostProcessor第0次被调动
dog属性值:PropertyValues: length=0
修改dog的作用域为prototype

BeanFactoryPostProcessor第1次被调动
大家好, 我叫小明, 我今年3岁了

========测试方法结束=======

10--Spring BeanPostProcessor和Bea

1. BeanPostProcessor

2. BeanFactoryPostProcessor

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