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后置处理_编程
=============

1 实现BeanPostProcessor接口

/src/main/java/cn/tedu/injection/MyBeanPostProcessor.java：

public class MyBeanPostProcessor implements BeanPostProcessor {
    private Logger logger = Logger.getLogger(MyBeanPostProcessor.class);

    @Override
    public Object postProcessBeforeInitialization(
        Object bean, String beanName) throws BeansException {
        logger.debug("MyBeanPostProcessor.postProcessBeforeInitialization");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(
        Object bean, String beanName) throws BeansException {
        logger.debug("MyBeanPostProcessor.postProcessAfterInitialization");
        return bean;
    }
}

2 通过配置告诉Spring框架

/src/main/resources/applicationContext.xml：

<bean id="myBeanPostProcessor" class="cn.tedu.injection.MyBeanPostProcessor" />

Before ApplicationContext
MyBeanPostProcessor.postProcessBeforeInitialization \
MyBeanPostProcessor.postProcessAfterInitialization  |
MyBeanPostProcessor.postProcessBeforeInitialization |
MyBeanPostProcessor.postProcessAfterInitialization  |
MyBeanPostProcessor.postProcessBeforeInitialization |
MyBeanPostProcessor.postProcessAfterInitialization  |
MyBeanPostProcessor.postProcessBeforeInitialization |
MyBeanPostProcessor.postProcessAfterInitialization  |
MyBeanPostProcessor.postProcessBeforeInitialization | 后置处理对Spring工厂创建的
MyBeanPostProcessor.postProcessAfterInitialization  | 所有对象而非特定对象做加工
MyBeanPostProcessor.postProcessBeforeInitialization |
MyBeanPostProcessor.postProcessAfterInitialization  |
MyBeanPostProcessor.postProcessBeforeInitialization |
MyBeanPostProcessor.postProcessAfterInitialization  |
MyBeanPostProcessor.postProcessBeforeInitialization |
MyBeanPostProcessor.postProcessAfterInitialization  |
MyBeanPostProcessor.postProcessBeforeInitialization |
MyBeanPostProcessor.postProcessAfterInitialization  /
After ApplicationContext
Before getBean
Product.Product
Product.setName
MyBeanPostProcessor.postProcessBeforeInitialization - 在初始化前加工处理
Product.afterPropertiesSet                          - 接口中的初始化方法
Product.init                                        - 自定义的初始化方法
MyBeanPostProcessor.postProcessAfterInitialization  - 在初始化后加工处理
After getBean
cn.tedu.injection.Product@20f5239f

例程：Injection

3 对不同类型的对象以不同方式加工

在实现加工处理的方法中对传入对象的类型做判断，执行有针对性的处理。

/src/main/java/cn/tedu/injection/MyBeanPostProcessor.java：

public class MyBeanPostProcessor implements BeanPostProcessor {
    private Logger logger = Logger.getLogger(MyBeanPostProcessor.class);

    @Override
    public Object postProcessBeforeInitialization(
        Object bean, String beanName) throws BeansException {
        logger.debug("MyBeanPostProcessor.postProcessBeforeInitialization");
        if (bean instanceof Product)
            ((Product)bean).setName("computer");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(
        Object bean, String beanName) throws BeansException {
        logger.debug("MyBeanPostProcessor.postProcessAfterInitialization");
        if (bean instanceof Product)
            ((Product)bean).setName("tablet");
        return bean;
    }
}

例程：Injection