Does f:viewParam only pass query string in url when first page uses the same managed bean as the second page?
jsf, jsf-2, view-scope
Solution
`includeViewParams` works only if both the source and target view have the desired view parameters declared as `<f:viewParam>`.
So, in your parituclar case, you need to put the `<f:viewParam>`s with very same `name` in both the `search.xhtml` and `results.xhtml`. Under the covers, the `includeViewParams` namely only grabs the view params of the current view and then only applies the ones which are also declared in the target view.
See also:
- What can <f:metadata>, <f:viewParam> and <f:viewAction> be used for?
Unrelated to the concrete problem, you seem to effectively want a GET form. In that case, there is a better way for that than performing a POST-Redirect-GET with parameters. Look at the bottom of the above "See also" link.
Problem
Let's use a search page and a results page for example. If i have a ViewScoped bean that handles my search page and my results page, i'm able to pass parameters through the url using something like this: search.xhtml ``` <p:commandButton value="Search" type="submit" action="#{searchBacker.search}" > ``` backing bean ``` @ManagedBean(name="search") @ViewScoped public class searchBacker extends AbstractBacking { private String firstName = null; private String lastName = null; private String results = null; public String search() { return "results?faces-redirect=true&includeViewParams=true"; } public void getResults() { MyDAO dao = new MyDAO(); results = dao.getResults(firstName, lastName); } //getters and setters } ``` results.xhtml ``` <f:metadata> <f:event type="preRenderView" listener="#{searchBacker.getResults}" /> <f:viewParam name="firstName" value="#{searchBacker.firstName}"/> <f:viewParam name="lastName" value="#{searchBacker.lastName}"/> </f:metadata> ``` Now lets say i have two managed beans - one for the search page and one for the results page. Will the query string still be built in the url with 2 different managed beans or does this only work when using the same managed bean for both pages? UPDATE I have the same `<f:viewParam>` on my search.xhtml and results.xhtml page, but the only difference is that my `f:viewParam value` points to a different backer in my results.xhtml than in my search.xhtml. When i do this, no params get passed through the url. When I point my `f:viewParam value` in results.xhtml to the same backer that i use in search.xhtml, the param gets passed through the url just fine, but the value doesn't exist in the results backer where i need it. If i have duplicate `f:viewParam`s in my results.xhtml page - one with the search backer and one with the results backer, everything works fine. Is having 2 of the same `f:viewParam`s with both managed beans the correct way to do this? Examples: results.xhtml - params get passed through url, but are not available in my resultsBacker ``` <f:metadata> <f:viewParam name="firstName" value="#{searchBacker.firstName}"/> <f:viewParam name="lastName" value="#{searchBacker.lastName}"/> </f:metadata> ``` results.xhtml - no params get passed through url ``` <f:metadata> <f:viewParam name="firstName" value="#{resultsBacker.firstName}"/> <f:viewParam name="lastName" value="#{resultsBacker.lastName}"/> </f:metadata> ``` results.xhtml - params get passed through url and are available in my resultsBacker, but seems clunky. Is this the correct way to do this or am i still missing something? ``` <f:metadata> <f:viewParam name="firstName" value="#{searchBacker.firstName}"/> <f:viewParam name="firstName" value="#{resultsBacker.firstName}"/> <f:viewParam name="lastName" value="#{searchBacker.lastName}"/> <f:viewParam name="lastName" value="#{resultsBacker.lastName}"/> </f:metadata> ```