/**
*
* <li>forceLookup 为false时，优先返回(ActionMapping) request.getAttribute(STRUTS_ACTION_MAPPING_KEY)
* <li>forceLookup 为true时，每次都去获取ActionMapper实例 <br>
* <br>
* Finds and optionally creates an {@link ActionMapping}. if forceLookup is false, it first
* looks in the current request to see if one has already been found, otherwise, it creates it
* and stores it in the request. No mapping will be created in the case of static resource
* requests or unidentifiable requests for other servlets, for example.
*
* @param forceLookup if true, the action mapping will be looked up from the ActionMapper
* instance, ignoring if there is one in the request or not
*/
public ActionMapping findActionMapping(
HttpServletRequest request, HttpServletResponse response, boolean forceLookup) {
ActionMapping mapping = (ActionMapping) request.getAttribute(STRUTS_ACTION_MAPPING_KEY);
if (mapping == null || forceLookup) {
try {
// ActionMapper默认实例是{ @link org.apache.struts2.dispatcher.mapper.DefaultActionMapper}
mapping =
dispatcher
.getContainer()
.getInstance(ActionMapper.class)
.getMapping(request, dispatcher.getConfigurationManager());
if (mapping != null) {
// 设置mapping到request属性，
request.setAttribute(STRUTS_ACTION_MAPPING_KEY, mapping);
}
} catch (Exception ex) {
dispatcher.sendError(
request, response, servletContext, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, ex);
}
}
return mapping;
}
/**
* Load Action class for mapping and invoke the appropriate Action method, or go directly to the
* Result.
*
* <p>This method first creates the action context from the given parameters, and then loads an
* <tt>ActionProxy</tt> from the given action name and namespace. After that, the Action method is
* executed and output channels through the response object. Actions not found are sent back to
* the user via the {@link Dispatcher#sendError} method, using the 404 return code. All other
* errors are reported by throwing a ServletException.
*
* @param request the HttpServletRequest object
* @param response the HttpServletResponse object
* @param mapping the action mapping object
* @throws ServletException when an unknown error occurs (not a 404, but typically something that
* would end up as a 5xx by the servlet container)
* @param context Our ServletContext object
*/
public void serviceAction(
HttpServletRequest request,
HttpServletResponse response,
ServletContext context,
ActionMapping mapping)
throws ServletException {
Map<String, Object> extraContext = createContextMap(request, response, mapping, context);
// If there was a previous value stack, then create a new copy and pass it in to be used by the
// new Action
ValueStack stack =
(ValueStack) request.getAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY);
boolean nullStack = stack == null;
if (nullStack) {
ActionContext ctx = ActionContext.getContext();
if (ctx != null) {
stack = ctx.getValueStack();
}
}
if (stack != null) {
extraContext.put(ActionContext.VALUE_STACK, valueStackFactory.createValueStack(stack));
}
String timerKey = "Handling request from Dispatcher";
try {
UtilTimerStack.push(timerKey);
String namespace = mapping.getNamespace();
String name = mapping.getName();
String method = mapping.getMethod();
Configuration config = configurationManager.getConfiguration();
ActionProxy proxy =
config
.getContainer()
.getInstance(ActionProxyFactory.class)
.createActionProxy(namespace, name, method, extraContext, true, false);
request.setAttribute(
ServletActionContext.STRUTS_VALUESTACK_KEY, proxy.getInvocation().getStack());
// if the ActionMapping says to go straight to a result, do it!
if (mapping.getResult() != null) {
Result result = mapping.getResult();
result.execute(proxy.getInvocation());
} else {
proxy.execute();
}
// If there was a previous value stack then set it back onto the request
if (!nullStack) {
request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, stack);
}
} catch (ConfigurationException e) {
// WW-2874 Only log error if in devMode
if (devMode) {
String reqStr = request.getRequestURI();
if (request.getQueryString() != null) {
reqStr = reqStr + "?" + request.getQueryString();
}
LOG.error("Could not find action or result\n" + reqStr, e);
} else {
if (LOG.isWarnEnabled()) {
LOG.warn("Could not find action or result", e);
}
}
sendError(request, response, context, HttpServletResponse.SC_NOT_FOUND, e);
} catch (Exception e) {
if (handleException || devMode) {
sendError(request, response, context, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);
} else {
throw new ServletException(e);
}
} finally {
UtilTimerStack.pop(timerKey);
}
}