我使用BalusC blog提供的代码处理我的PRG，并在刷新POST请求时阻止双重提交。但它会杀死＆＃34; ajax功能，现在ajax不断刷新整个页面而不是一个组件。
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.faces.FacesException;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.component.UIInput;
import javax.faces.component.UIViewRoot;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;
import javax.servlet.http.HttpServletRequest;
/**
* Implement the POST-Redirect-GET pattern for JSF.
* <p>
* This phaselistener is designed to be used for JSF 1.2 with request scoped beans of which its
* facesmessages and input values should be retained in the new GET request. If you're using session
* scoped beans only, then you can safely remove the <tt>saveUIInputValues()</tt> and
* <tt>restoreUIInputValues()</tt> methods to save (little) performance. If you're using JSF 1.1,
* then you can also remove the <tt>saveViewRoot()</tt> and <tt>restoreViewRoot</tt> methods,
* because it is not needed with its view state saving system.
*
* @author BalusC
* @link http://balusc.blogspot.com/2007/03/post-redirect-get-pattern.html
*/
public class PostRedirectGetListener implements PhaseListener {
// Init ---------------------------------------------------------------------------------------
private static final String PRG_DONE_ID = "PostRedirectGetListener.postRedirectGetDone";
private static final String SAVED_VIEW_ROOT_ID = "PostRedirectGetListener.savedViewRoot";
private static final String ALL_FACES_MESSAGES_ID = "PostRedirectGetListener.allFacesMessages";
private static final String ALL_UIINPUT_VALUES_ID = "PostRedirectGetListener.allUIInputValues";
// Actions ------------------------------------------------------------------------------------
/**
* @see javax.faces.event.PhaseListener#getPhaseId()
*/
public PhaseId getPhaseId() {
// Only listen during the render response phase.
return PhaseId.RENDER_RESPONSE;
}
/**
* @see javax.faces.event.PhaseListener#beforePhase(javax.faces.event.PhaseEvent)
*/
public void beforePhase(PhaseEvent event) {
// Prepare.
FacesContext facesContext = event.getFacesContext();
ExternalContext externalContext = facesContext.getExternalContext();
HttpServletRequest request = (HttpServletRequest) externalContext.getRequest();
Map<String, Object> sessionMap = externalContext.getSessionMap();
if ("POST".equals(request.getMethod())) {
// Save viewroot, facesmessages and UIInput values from POST request in session so that
// they'll be available on the subsequent GET request.
saveViewRoot(facesContext);
saveFacesMessages(facesContext);
saveUIInputValues(facesContext);
// Redirect POST request to GET request.
redirect(facesContext);
// Set the PRG toggle.
sessionMap.put(PRG_DONE_ID, true);
} else if (sessionMap.containsKey(PRG_DONE_ID)) {
// Restore any viewroot, facesmessages and UIInput values in the GET request.
restoreViewRoot(facesContext);
restoreFacesMessages(facesContext);
restoreUIInputValues(facesContext);
// Remove the PRG toggle.
sessionMap.remove(PRG_DONE_ID);
}
}
/**
* @see javax.faces.event.PhaseListener#afterPhase(javax.faces.event.PhaseEvent)
*/
public void afterPhase(PhaseEvent event) {
// Do nothing.
}
// Helpers ------------------------------------------------------------------------------------
/**
* Save the current viewroot of the given facescontext in session. This is important in JSF 1.2,
* because the viewroot would be lost in the new GET request and will only be created during
* the afterPhase of RENDER_RESPONSE. But as we need to restore the input values in the
* beforePhase of RENDER_RESPONSE, we have to save and restore the viewroot first ourselves.
* @param facesContext The involved facescontext.
*/
private static void saveViewRoot(FacesContext facesContext) {
UIViewRoot savedViewRoot = facesContext.getViewRoot();
facesContext.getExternalContext().getSessionMap()
.put(SAVED_VIEW_ROOT_ID, savedViewRoot);
}
/**
* Save all facesmessages of the given facescontext in session. This is done so because the
* facesmessages are purely request scoped and would be lost in the new GET request otherwise.
* @param facesContext The involved facescontext.
*/
private static void saveFacesMessages(FacesContext facesContext) {
// Prepare the facesmessages holder in the sessionmap. The LinkedHashMap has precedence over
// HashMap, because in a LinkedHashMap the FacesMessages will be kept in order, which can be
// very useful for certain error and focus handlings. Anyway, it's just your design choice.
Map<String, List<FacesMessage>> allFacesMessages =
new LinkedHashMap<String, List<FacesMessage>>();
facesContext.getExternalContext().getSessionMap()
.put(ALL_FACES_MESSAGES_ID, allFacesMessages);
// Get client ID's of all components with facesmessages.
Iterator<String> clientIdsWithMessages = facesContext.getClientIdsWithMessages();
while (clientIdsWithMessages.hasNext()) {
String clientIdWithMessage = clientIdsWithMessages.next();
// Prepare client-specific facesmessages holder in the main facesmessages holder.
List<FacesMessage> clientFacesMessages = new ArrayList<FacesMessage>();
allFacesMessages.put(clientIdWithMessage, clientFacesMessages);
// Get all messages from client and add them to the client-specific facesmessage list.
Iterator<FacesMessage> facesMessages = facesContext.getMessages(clientIdWithMessage);
while (facesMessages.hasNext()) {
clientFacesMessages.add(facesMessages.next());
}
}
}
/**
* Save all input values of the given facescontext in session. This is done specific for request
* scoped beans, because its properties would be lost in the new GET request otherwise.
* @param facesContext The involved facescontext.
*/
private static void saveUIInputValues(FacesContext facesContext) {
// Prepare the input values holder in sessionmap.
Map<String, Object> allUIInputValues = new HashMap<String, Object>();
facesContext.getExternalContext().getSessionMap()
.put(ALL_UIINPUT_VALUES_ID, allUIInputValues);
// Pass viewroot children to the recursive method which saves all input values.
saveUIInputValues(facesContext, facesContext.getViewRoot().getChildren(), allUIInputValues);
}
/**
* A recursive method to save all input values of the given facescontext in session.
* @param facesContext The involved facescontext.
*/
private static void saveUIInputValues(
FacesContext facesContext, List<UIComponent> components, Map<String, Object> allUIInputValues)
{
// Walk through the components and if it is an instance of UIInput, then save the value.
for (UIComponent component : components) {
if (component instanceof UIInput) {
UIInput input = (UIInput) component;
allUIInputValues.put(input.getClientId(facesContext), input.getValue());
}
// Pass the children of the current component back to this recursive method.
saveUIInputValues(facesContext, component.getChildren(), allUIInputValues);
}
}
/**
* Invoke a redirect to the same URL as the current action URL.
* @param facesContext The involved facescontext.
*/
private static void redirect(FacesContext facesContext) {
// Obtain the action URL of the current view.
String url = facesContext.getApplication().getViewHandler().getActionURL(
facesContext, facesContext.getViewRoot().getViewId());
try {
// Invoke a redirect to the action URL.
facesContext.getExternalContext().redirect(url);
} catch (IOException e) {
// Uhh, something went seriously wrong.
throw new FacesException("Cannot redirect to " + url + " due to IO exception.", e);
}
}
/**
* Restore any viewroot from session in the given facescontext.
* @param facesContext The involved FacesContext.
*/
private static void restoreViewRoot(FacesContext facesContext) {
// Remove the saved viewroot from session.
UIViewRoot savedViewRoot = (UIViewRoot)
facesContext.getExternalContext().getSessionMap().remove(SAVED_VIEW_ROOT_ID);
// Restore it in the given facescontext.
facesContext.setViewRoot(savedViewRoot);
}
/**
* Restore any facesmessages from session in the given FacesContext.
* @param facesContext The involved FacesContext.
*/
@SuppressWarnings("unchecked")
private static void restoreFacesMessages(FacesContext facesContext) {
// Remove all facesmessages from session.
Map<String, List<FacesMessage>> allFacesMessages = (Map<String, List<FacesMessage>>)
facesContext.getExternalContext().getSessionMap().remove(ALL_FACES_MESSAGES_ID);
// Restore them in the given facescontext.
for (Entry<String, List<FacesMessage>> entry : allFacesMessages.entrySet()) {
for (FacesMessage clientFacesMessage : entry.getValue()) {
facesContext.addMessage(entry.getKey(), clientFacesMessage);
}
}
}
/**
* Restore any input values from session in the given FacesContext.
* @param facesContext The involved FacesContext.
*/
@SuppressWarnings("unchecked")
private static void restoreUIInputValues(FacesContext facesContext) {
// Remove all input values from session.
Map<String, Object> allUIInputValues = (Map<String, Object>)
facesContext.getExternalContext().getSessionMap().remove(ALL_UIINPUT_VALUES_ID);
// Restore them in the given facescontext.
for (Entry<String, Object> entry : allUIInputValues.entrySet()) {
UIInput input = (UIInput) facesContext.getViewRoot().findComponent(entry.getKey());
input.setValue(entry.getValue());
}
}