Pass parameters to a page

You need page parameters when the URL itself has to carry data: a link in an email that confirms a subscription, a product page that people bookmark, a search page that other sites link to. Inside your application, passing objects or models to a page constructor is usually simpler.

Build the parameters

PageParameters holds name-value pairs, like a query string. add and set both return the PageParameters, so you can chain them. Values are stored as strings; Wicket calls toString() on what you pass.

PageParameters parameters = new PageParameters()
    .add("id", 42)
    .add("tab", "reviews");

set(name, value) replaces any value the name already has. add(name, value) appends another value, so add("tag", "red").add("tag", "blue") produces ?tag=red&tag=blue. remove(name) deletes a parameter.

Send the user to a page with parameters

Call setResponsePage with the page class and the parameters, for example in the onClick of a link or the onSubmit of a form:

setResponsePage(ProductPage.class, new PageParameters().add("id", product.getId()));

To render a plain link to the page without a click handler, use a BookmarkablePageLink, described in Link to a page.

Without a mount, the URL contains the class name: /wicket/bookmarkable/com.example.ProductPage?id=42&tab=reviews. Give pages readable URLs shows how to turn this into /products/42.

Read the parameters in the page

Give the page a constructor that takes PageParameters and pass them to super. The page keeps them, so getPageParameters() returns them later, and Wicket uses them when it builds the URL of the page.

ProductPage.java

public class ProductPage extends WebPage {

    public ProductPage(PageParameters parameters) {
        super(parameters);

        long id = parameters.get("id").toLong();
        // products is your own data access service
        IModel<Product> product = LoadableDetachableModel.of(() -> products.find(id));

        add(new Label("name", product.map(Product::getName)));
    }
}

A page with a PageParameters constructor, or with a constructor without arguments, is bookmarkable: Wicket can create it from the URL alone, without anything in the session.

Convert a parameter to a number, date or enum

get(name) never returns null. It returns a StringValue, which is empty when the parameter is missing, and which converts the text for you:

Parameters come from the user, who can edit the URL. Decide what a missing or broken value means. To answer with a 404, throw an AbortWithHttpErrorCodeException:

Long id = parameters.get("id").toOptionalLong();
if (id == null) {
    throw new AbortWithHttpErrorCodeException(404);
}

getValues(name) returns all values of a parameter that occurs more than once, as a List<StringValue>.

Use indexed parameters

Besides named parameters, PageParameters holds indexed parameters. Wicket renders them as path segments after the page path, before the query string:

PageParameters parameters = new PageParameters()
    .set(0, "2026")
    .set(1, "october")
    .add("sort", "date");
// /archive/2026/october?sort=date when ArchivePage is mounted at /archive

Read them with get(0), get(1), and so on. A mount path with placeholders such as /archive/${year}/${month} gives the same URL with named parameters, which are easier to read in code.

Add a fragment to the URL

Since Wicket 10.4, PageParameters supports the fragment of a URL, the part after #.

PageParameters parameters = new PageParameters().add("id", 42);
parameters.setFragment("reviews");
setResponsePage(ProductPage.class, parameters);
// ...?id=42#reviews

Browsers do not send the fragment to the server, so you can set it on outgoing URLs but not read it from an incoming request.

Build a full URL for an email

A confirmation link in an email needs the protocol and host as well. mapUrlFor builds the URL of a page with its parameters, and the URL renderer of the request cycle makes it absolute:

RequestCycle cycle = RequestCycle.get();
Url url = cycle.mapUrlFor(ConfirmPage.class, new PageParameters().add("token", token));
String link = cycle.getUrlRenderer().renderFullUrl(url);