ApplicationContextAware接口的作用

加載Spring配置文件時，如果Spring配置文件中所定義的Bean類實現了ApplicationContextAware 接口，那麼在加載Spring配置文件時，會自動調用ApplicationContextAware 接口中的

public void setApplicationContext(ApplicationContext context) throws BeansException

方法，獲得ApplicationContext對象。

前提必須在Spring配置文件中指定該類

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" />

正常情況:

public class AppManagerextendsContextLoaderListenerimplements  ServletContextListener {

    private ServletContext context;
    privateWebApplicationContext webApplicationContext;

    public voidcontextInitialized(ServletContextEvent sce) {
        this.context = sce.getServletContext();
       this.webApplicationContext = WebApplicationContextUtils.getRequiredWebApplicationContext(context);
       this.context.setAttribute("WEBAPPLICATIONCONTEXT", webApplicationContext);       ｝

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