关于Spring的BeanPostProcessor

BeanPostProcessor接口作用是：如果我们需要在Spring容器完成Bean的实例化、配置和其他的初始化前后添加一些自己的逻辑处理，我们就可以定义一个或者多个BeanPostProcessor接口的实现，然后注册到容器中。、

比如如果我们使用spring整合hibernate，我们可以在容器实例化前先加载hibernate的配置文件：

public class MappingFactoryBean implements FactoryBean {
    private static Logger log = LoggerFactory
            .getLogger(MappingFactoryBean.class);

public Object getObject() throws Exception {
        List<String> configs = ApplicationContext.getContext().getApplication()
                .getMappingConfigs();
        log.debug("************* hibernate configs: " + configs);
        return configs.toArray(new String[configs.size()]);
    }

public Class<?> getObjectType() {
        return String[].class;
    }

public boolean isSingleton() {
        return true;
    }
}

public class MappingAutowiring implements BeanPostProcessor {
    private static Logger log = LoggerFactory
            .getLogger(MappingAutowiring.class);

private String[] mappingResources;

public String[] getMappingResources() {
        return mappingResources;
    }

public void setMappingResources(String[] mappingResources) {
        this.mappingResources = mappingResources;
    }

public Object postProcessBeforeInitialization(Object bean, String beanName)
            throws BeansException {
        if (bean instanceof LocalSessionFactoryBean) {
            log.debug("============ MappingAutowiring: " + mappingResources);
            ((LocalSessionFactoryBean) bean)
                    .setMappingResources(mappingResources);
        }
        return bean;
    }

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

beans.xml 配置如下：

<bean id="mappingAutowiring"
        class="xx.MappingAutowiring">
        <property name="mappingResources" ref="mappingResources" />
    </bean>
    <bean id="mappingResources"
        class="xx.MappingFactoryBean" />