Author: zhuam
昨晚一口氣看完了夏昕寫的<
今天下載了最新的WebWork2版本, 開始了源碼分析,這份文檔只能算是我的個人筆記,也沒時間細細校對,且個人能力有限,難免有許多分析錯誤或筆誤的地方,還望各位指正.
WebWork1.x版本是采用緊偶合的架構,類似如Struts ,而WebWork2.x版本後采用了新的架構 WebWork2.x+XWork1.x 就是因為他采用了這樣架構所以才吸引我去看他源碼的啊!新的架構分離了與Servlet API的緊偶合,這樣我們的系統結構將更加的清晰,且系統測試與系統移植將來的更加方便,其實WebWork1.x版本我也沒有看過,所謂的緊偶合也是看網上是這麼說的,沒有發言權啊,呵呵!
在新的架構中WebWork2.x的作用是負責將用戶的HTTP請求分離出來,使的請求完全的脫離Servlet API,然後將這些請求用Map的方式傳入XWork1.x,且XWork1.x通過Interceptor 將Map 中的數據傳到我們的VO中,然後由對應的自定義Action來調用.
下面首先來看WebWork2.x怎麼分離HTTP請求,其實他是通過ServletDispatcher來達到目的.代碼如下所示:
public static HashMap createContextMap(Map requestMap, Map parameterMap, Map sessionMap, Map applicationMap, HttpServletRequest request, HttpServletResponse response, ServletConfig servletConfig) {
HashMap extraContext = new HashMap();
//存放HTTP中上傳文件的request session請求
extraContext.put(ActionContext.PARAMETERS, parameterMap);
extraContext.put(ActionContext.SESSION, sessionMap);
extraContext.put(ActionContext.APPLICATION, applicationMap);
extraContext.put(ActionContext.LOCALE, (locale == null) ? request.getLocale() : locale);
extraContext.put(HTTP_REQUEST, request);
extraContext.put(HTTP_RESPONSE, response);
extraContext.put(SERVLET_CONFIG, servletConfig);
extraContext.put(ComponentInterceptor.COMPONENT_MANAGER, request.getAttribute(ComponentManager.COMPONENT_MANAGER_KEY));
// helpers to get Access to request/session/application scope
//這裡用於存放HTTP中的request session請求
extraContext.put("request", requestMap);
extraContext.put("session", sessionMap);
extraContext.put("application", applicationMap);
extraContext.put("parameters", parameterMap);
AttributeMap attrMap = new AttributeMap(extraContext);
extraContext.put("attr", attrMap);
return extraContext;
}
以上的是ServletDispatcher 中的方法createContextMap是用於將HTTP請求封裝到Map中去,且ServletDispatcher也是WebWork2.x的控制器,負責分離出Action, 他是通過service方法去調用serviceAction方法,然後由serviceAction來完成操作的,代碼如下:
public void serviceAction(HttpServletRequest request, HttpServletResponse response, String namespace, String actionName, Map requestMap, Map parameterMap, Map sessionMap, Map applicationMap) {
HashMap extraContext = createContextMap(requestMap, parameterMap, sessionMap, applicationMap, request, response, getServletConfig()); //實例化Map請求
extraContext.put(SERVLET_DISPATCHER, this);
// If there was a previous value stack, then create a new copy and pass it in to be used by the new Action
OgnlValueStack stack = (OgnlValueStack) request.getAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY);
if (stack != null) {
extraContext.put(ActionContext.VALUE_STACK,new OgnlValueStack(stack));
}
try {
ActionProxy proxy = ActionProxyFactory.getFactory().createActionProxy(namespace, actionName, extraContext);
//這裡actionName是通過兩道getActionName解析出來的,下面是ServletDispatcher的 TODO: QUESTIONS轉載出來讓大家看一看
* 1) What unit is maxSize of attachments in? (assuming bytes for now)
* 2) Isn't error message wrong in catch of try/catch in service() method?
* 3) Why is getActionName(String) not declared public? (The fix would not be an API addition so this could be ( done for pre 2.1)
* 4) Why does createContextMap(...) return a HashMap and not a Map? (2.1 api change)
* 5) Why doesn't getNameSpace(request) get the servlet path in the same way that getActionName(request) does?
* 6) Why does getParameterMap throw an IOException? Can't see a reason for that. (2.1 api change)
*/
request.setAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY, proxy.getInvocation().getStack());
proxy.execute();
// If there was a previous value stack then set it back onto the request
if (stack != null){
request.setAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY,stack);
}
} catch (ConfigurationException e) {
log.error("Could not find action", e);
sendError(request, response, HttpServletResponse.SC_NOT_FOUND, e);
} catch (Exception e) {
log.error("Could not execute action", e);
sendError(request, response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);
}
}
