Struts2 BusinessException

最近更新STRUTS的版本到2.1.8 ，发现异常发生后，没有收到异常邮件了，
配置

<global-exception-mappings>  
            <exception-mapping result="normalException"  
                exception="com.esc.common.exception.BusinessException">  
            </exception-mapping>  
        </global-exception-mappings> 

BusinessException继承了RuntimeExcption，2.0的时候，凡是非BusinessException子类，就会向外抛出，那么就能在我下面的catch块中捕获到异常
代码

//我的filter，在struts的filter之前  
public void doFilter(ServletRequest org0, ServletResponse org1,  
            FilterChain chain) throws IOException, ServletException {  
        HttpServletRequest request = (HttpServletRequest) org0;  
        HttpServletResponse response = (HttpServletResponse) org1;  
        try {  
            ..........  
            chain.doFilter(org0, org1);//到STRUTS的FILTER  
            ..........  
        }catch (Exception e) {//现在这里现在永远到不了  
            sendEmailIfNecessary(e, request);//发邮件  
        }  

查了很久，发现此版本不再抛异常了，org.apache.struts2.dispatcher.Dispatcher类serviceAction方法代码

public void serviceAction(HttpServletRequest request, HttpServletResponse response, ServletContext context,  
                             ActionMapping mapping) throws ServletException {  
  
       .......;  
       try {  
           ......;  
       } catch (ConfigurationException e) {//异常处理  
        // WW-2874 Only log error if in devMode  
        if(devMode) {  
            LOG.error("Could not find action or result", e);  
        }  
        else {  
            LOG.warn("Could not find action or result", e);  
        }  
           sendError(request, response, context, HttpServletResponse.SC_NOT_FOUND, e);  
       } catch (Exception e) {  
           //这里以前是throw new ServletException(e);  
           sendError(request, response, context, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);  
       } finally {  
           UtilTimerStack.pop(timerKey);  
       }  
   }  

来看看sendError的代码

public void sendError(HttpServletRequest request, HttpServletResponse response,  
           ServletContext ctx, int code, Exception e) {  
       if (devMode) {  
//开发模式，即Struts的配置文件中有设如下设置<constant name="struts.devMode" value="true" />  
           response.setContentType("text/html");  
  
           try {  
               FreemarkerManager mgr = getContainer().getInstance(FreemarkerManager.class);  
  
               freemarker.template.Configuration config = mgr.getConfiguration(ctx);  
               Template template = config.getTemplate("/org/apache/struts2/dispatcher/error.ftl");  
  
               List<Throwable> chain = new ArrayList<Throwable>();  
               Throwable cur = e;  
               chain.add(cur);  
               while ((cur = cur.getCause()) != null) {  
                   chain.add(cur);  
               }  
  
               HashMap<String,Object> data = new HashMap<String,Object>();  
               data.put("exception", e);  
               data.put("unknown", Location.UNKNOWN);  
               data.put("chain", chain);  
               data.put("locator", new Locator());  
               template.process(data, response.getWriter());  
               response.getWriter().close();  
           } catch (Exception exp) {  
               try {  
                   response.sendError(code, "Unable to show problem report: " + exp);  
               } catch (IOException ex) {  
                   // we're already sending an error, not much else we can do if more stuff breaks  
               }  
           }  
       } else {//普通模式  
           try {  
               // WW-1977: Only put errors in the request when code is a 500 error  
               if (code == HttpServletResponse.SC_INTERNAL_SERVER_ERROR) {  
                   // send a http error response to use the servlet defined error handler  
                   // 原来异常被这样处理掉了  
                   request.setAttribute("javax.servlet.error.exception", e);  
  
                   // for compatibility  
                   request.setAttribute("javax.servlet.jsp.jspException", e);  
               }  
  
               // send the error response  
               response.sendError(code, e.getMessage());  
           } catch (IOException e1) {  
               // we're already sending an error, not much else we can do if more stuff breaks  
           }  
       }  
   }  

再把结果说明白一点，
1、开发模式：异常不好拿了，异常信息被直接写到页面，不过没关系，开发嘛，这不正是你想要的吗
2、正常模式：通过request.getAttribute("javax.servlet.error.exception")或者request.getAttribute("javax.servlet.jsp.jspException")可以取得异常对象。