struts的消息处理

public class ActionException extends RuntimeException
{

    private ActionMessage actionMessage;

    public ActionException(String key)
    {
        actionMessage = new ActionMessage(key);
    }

    public String getMessage()
    {
        if(actionMessage != null)
            return actionMessage.toString();
        else
            return super.getMessage();
    }
}

public class ActionExceptionHandler extends ExceptionHandler
{

    public ActionExceptionHandler()
    {
    }

    public ActionForward execute(Exception ex, ExceptionConfig config, ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response)
        throws ServletException
    {
        if(ex instanceof ActionException)
        {
            ActionMessages errors = new ActionMessages();
            errors.add("org.apache.struts.action.GLOBAL_MESSAGE", ((CannaException)ex).getActionMessage());
            saveErrors(request, errors);
            ActionForward forward = mapping.getInputForward();
            if(forward == null)
                forward = new ActionForward(config.getPath());
            return forward;
        } else
        {
            return super.execute(ex, config, mapping, form, request, response);
        }
    }

    protected void saveErrors(HttpServletRequest request, ActionMessages errors)
    {
        if(errors == null || errors.isEmpty())
        {
            request.removeAttribute("org.apache.struts.action.ERROR");
            return;
        } else
        {
            request.setAttribute("org.apache.struts.action.ERROR", errors);
            return;
        }
    }
}

		<exception key="exception.actionception" type="com.ActionException"
			handler="com.ActionExceptionHandler" />
	

	<message-resources parameter="com.LocalStrings"  
		null="false" />