JSF 2.0.无法在preRenderView事件处理程序中获取POST参数和cookie

Question

我正在努力开发一项服务.

关键是我的index.xhtml应该从HTTP Request获取参数(POST和GET)和cookie.

我尝试过组合<f:metadata>并<f:event type="preRenderView">像这样:

<f:metadata>  
    <f:event type="preRenderView" listener="#{deConversation.start}"/>  
</f:metadata>

deConversation.start的代码:

public void start(ComponentSystemEvent event) {
    System.out.println("checkLogin");
    HttpServletRequest request = SsoHelper.getRequest();
    String requestSessId = SsoHelper.getRequestSessionId(request);
    String requestRedirect = SsoHelper.getRequestRedirect(request);

    System.out.println("sessId " + requestSessId);

    if (requestRedirect == null || requestRedirect.isEmpty()) {
        requestRedirect = "self";
    }

    if (requestSessId != null) {
        trySessId(requestSessId, requestRedirect);
    }

    externalResourcesHandler.setExternalRedirect(requestRedirect);
    tryToBeginConversation();

    if (!isAuthorized()) {
        SsoHelper.performNavigation("auth");
    }
}

SsoHelper只提供这样的api:

public static String getRequestSessionId(HttpServletRequest request) {
    Map<String, Object> cookieMap = FacesContext.getCurrentInstance().getExternalContext().getRequestCookieMap();
    String requestDeSessionId = null;
    if (cookieMap.containsKey("de_session_id")) {
        requestDeSessionId = ((Cookie) cookieMap.get("de_session_id")).getValue();
    }
    return requestDeSessionId;
}

public static String getRequestRedirect(HttpServletRequest request) {
    return getRequestParam(request, "redirect", "self");
}

public static String getRequestExternalCss(HttpServletRequest request) {
    return getRequestParam(request, "externalcss", null);
}

public static String getRequestParam(HttpServletRequest request, String name, String defaultValue) {
    String[] paramValues = HttpServletRequestHelper.getParamValues(request, name);
    String paramValue = null;
    if (paramValues != null && paramValues.length != 0) {
        paramValue = paramValues[0];
    }
    if(paramValue == null){
        paramValue = defaultValue;
    }
    return paramValue;
}

public static HttpServletRequest getRequest() {
    return (HttpServletRequest) FacesContext.getCurrentInstance().getExternalContext().getRequest();
}

public static void performNavigation(String destination) {
    FacesContext context = FacesContext.getCurrentInstance();
    ConfigurableNavigationHandler handler = (ConfigurableNavigationHandler) context.getApplication().getNavigationHandler();
    handler.performNavigation(destination);
}

关键是我无法在方法start()中获得任何POST参数或cookie.我只能获得GET参数.

是否有可能使用<f:event type="preRenderView">？读取cookie和POST参数？

Answer 1

我认为您应该使用 @PostConstruct 调用 init 方法，以便在页面呈现之前调用 init() 并采用全局变量来分配变量中的 Session 或 Cookies 值，这样您就可以实现您的要求。

例子：

@PostConstruct
public void init(){
    // Your Response
    Map request = (Map)FacesContext.getCurrentInstance().getExternalContext().getResponse();
    request.get("Your Key");

    // Cookies
    Map cookie = FacesContext.getCurrentInstance().getExternalContext().getRequestCookieMap();
    cookie.get("Your Key");

    Map session = FacesContext.getCurrentInstance().getExternalContext().getSessionMap();
    session.get("Your Key"); 
}

试试这个我想它会对你有帮助。