spring 獲得ApplicationContext

</pre>在spring mvc項目中，可以通過實現<pre code_snippet_id="1602194" snippet_file_name="blog_20160308_2_8772120" name="code" class="java">ApplicationContextAware

來獲得ApplicationContext，

public class ContextHolder implements ApplicationContextAware {

 private static ApplicationContext context;

}

實現接口中方法

    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        context = applicationContext;
    }

然後注入實現類：

<bean id="SpringContextHolder" class="com.*.ContextHolder"></bean>

原理：

類AbstractApplicationContext中的prepareBeanFactory這個方法中向beanFactory註冊了一個beanPostProcessor。


beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));

ApplicationContextAwareProcessor 在初始化前會執行this.invokeAwareInterfaces(bean);

private void invokeAwareInterfaces(Object bean) {
        if(bean instanceof Aware) {
            if(bean instanceof EnvironmentAware) {
                ((EnvironmentAware)bean).setEnvironment(this.applicationContext.getEnvironment());
            }

            if(bean instanceof EmbeddedValueResolverAware) {
                ((EmbeddedValueResolverAware)bean).setEmbeddedValueResolver(new ApplicationContextAwareProcessor.EmbeddedValueResolver(this.applicationContext.getBeanFactory()));
            }

            if(bean instanceof ResourceLoaderAware) {
                ((ResourceLoaderAware)bean).setResourceLoader(this.applicationContext);
            }

            if(bean instanceof ApplicationEventPublisherAware) {
                ((ApplicationEventPublisherAware)bean).setApplicationEventPublisher(this.applicationContext);
            }

            if(bean instanceof MessageSourceAware) {
                ((MessageSourceAware)bean).setMessageSource(this.applicationContext);
            }

           <span style="color:#ff0000;"> if(bean instanceof ApplicationContextAware) {
                ((ApplicationContextAware)bean).setApplicationContext(this.applicationContext);
            }</span>
        }
     //調用ApplicationContextAware接口實現類的setApplicationContext方法。
    }

對了 這個不能忘了 web.xml裏

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>