ApplicationContextAware接口的作用

加载Spring配置文件时，如果Spring配置文件中所定义的Bean类实现了ApplicationContextAware 接口，那么在加载Spring配置文件时，会自动调用ApplicationContextAware 接口中的

public void setApplicationContext(ApplicationContext context) throws BeansException

方法，获得ApplicationContext对象。

前提必须在Spring配置文件中指定该类（SpringTest(实现ApplicationContextAware的类)必须要加入spring bean去管理，可以用Compnent注解或在xml文件去配。）

public class ApplicationContextRegister implements ApplicationContextAware {

private Log log = LogFactory.getLog(getClass());

public void setApplicationContext(ApplicationContext applicationContext)
   throws BeansException {
  ContextUtils.setApplicationContext(applicationContext);
  log.debug("ApplicationContext registed");
}

}

public class ContextUtils {

private static ApplicationContext applicationContext;

private static Log log = LogFactory.getLog(ContextUtils.class);

public static void setApplicationContext(ApplicationContext applicationContext) {
  synchronized (ContextUtils.class) {
   log.debug("setApplicationContext, notifyAll");
   ContextUtils.applicationContext = applicationContext;
   ContextUtils.class.notifyAll();
  }
}

public static ApplicationContext getApplicationContext() {
  synchronized (ContextUtils.class) {
   while (applicationContext == null) {
    try {
     log.debug("getApplicationContext, wait...");
     ContextUtils.class.wait(60000);
     if (applicationContext == null) {
      log.warn("Have been waiting for ApplicationContext to be set for 1 minute", new Exception());
     }
    } catch (InterruptedException ex) {
     log.debug("getApplicationContext, wait interrupted");
    }
   }
   return applicationContext;
  }
}

public static Object getBean(String name) {
  return getApplicationContext().getBean(name);
}

}

配置文件:<bean class="com.sinotrans.framework.core.support.ApplicationContextRegister" />

正常情况:

1. public class AppManagerextends ContextLoaderListener implements  ServletContextListener {  
2.  
3.     private ServletContext context;  
4.     private WebApplicationContext webApplicationContext;  
5.  
6.     public void contextInitialized(ServletContextEvent sce) {  
7.         this.context = sce.getServletContext();  
8.         this.webApplicationContext = WebApplicationContextUtils.getRequiredWebApplicationContext(context);  
9.         this.context.setAttribute("WEBAPPLICATIONCONTEXT", webApplicationContext);      ｝ 

1. HttpSession session = request.getSession();  
2. WebApplicationContext webApplicationContext = (WebApplicationContext)session.getServletContext().getAttribute("WEBAPPLICATIONCONTEXT");  
3. UnsubscribeEmailFacade unsubscribeEmailFacade = (UnsubscribeEmailFacade)webApplicationContext.getBean("unsubscribeEmailFacade");