在Struts2取得WebApplicationContext的方法

在Struts2获得WebApplicationContext的方法
1. Action实现implements ServletRequestAware,并实现setServletRequest()方法。

public void setServletRequest(HttpServletRequest request) {
		// TODO Auto-generated method stub
		this.request = request;
		
	}

以下是获得的方法:
A.

WebApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(request.getSession().getServletContext());
   ApplicationContext ac1 = WebApplicationContextUtils.getRequiredWebApplicationContext(request.getSession().getServletContext());//失败时抛出异常
   ApplicationContext ac2 = WebApplicationContextUtils.getWebApplicationContext(request.getSession().getServletContext()); //失败时返回null

B.

WebApplicationContext webApplicationContext = (WebApplicationContext)request.getSession().getServletContext().getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);