我需要知道从servlet访问JSF托管的Bean(该Bean具有应用程序范围)的最佳方法。
目前,我的servlet中有类似以下内容:
MyApplicationScopeBean bean = null;
try {
FacesContext fContext = FacesUtil.getFacesContext(req, resp);
ServletContext sc = (ServletContext) fContext.getExternalContext().getContext();
bean = (MyApplicationScopeBean) sc.getAttribute("myManagedBean");
} catch (Exception e) {
e.printStackTrace();
}
FacesUtil.java(如http://balusc.blogspot.com/2006/06/communication-in-jsf.html所述):
import javax.faces.FactoryFinder;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.faces.context.FacesContextFactory;
import javax.faces.lifecycle.Lifecycle;
import javax.faces.lifecycle.LifecycleFactory;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class FacesUtil {
// Getters -----------------------------------------------------------------------------------
public static FacesContext getFacesContext(
HttpServletRequest request, HttpServletResponse response)
{
// Get current FacesContext.
FacesContext facesContext = FacesContext.getCurrentInstance();
// Check current FacesContext.
if (facesContext == null) {
// Create new Lifecycle.
LifecycleFactory lifecycleFactory = (LifecycleFactory)
FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);
Lifecycle lifecycle = lifecycleFactory.getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
// Create new FacesContext.
FacesContextFactory contextFactory = (FacesContextFactory)
FactoryFinder.getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
facesContext = contextFactory.getFacesContext(
request.getSession().getServletContext(), request, response, lifecycle);
// Create new View.
UIViewRoot view = facesContext.getApplication().getViewHandler().createView(
facesContext, "");
facesContext.setViewRoot(view);
// Set current FacesContext.
FacesContextWrapper.setCurrentInstance(facesContext);
}
return facesContext;
}
// Helpers -----------------------------------------------------------------------------------
// Wrap the protected FacesContext.setCurrentInstance() in a inner class.
private static abstract class FacesContextWrapper extends FacesContext {
protected static void setCurrentInstance(FacesContext facesContext) {
FacesContext.setCurrentInstance(facesContext);
}
}
}
当我尝试从servlet中访问bean时,总是得到一个null值。您有什么建议吗?
我正在Tomcat 6上运行JSF 1.2。
谢谢您的帮助。