JSF Backing Bean Tips: Parameter Extractions and Redirects

These two quick JavaServer Faces (JSF) tips show how to extract request parameters and redirect page loads using a bean backing.

Extract a Request Parameter in JSF

When an application sends an HTTP GET request, it usually sends different kinds of parameters. Using a JSF backing bean, you can extract a request parameter like this:

...
FacesContext facesContext = FacesContext.getCurrentInstance();
String parameter_value = (String) facesContext.getExternalContext().
                              getRequestParameterMap().get("parameter_field_name");
...

JSF Redirect on Page Load

Here is a JSF backing bean method for executing a page redirect:

private void redirectToPage(String toUrl) {
        try {
            FacesContext ctx = FacesContext.getCurrentInstance();

            ExternalContext extContext = ctx.getExternalContext();
            String url = extContext.encodeActionURL(ctx.getApplication().
                                     getViewHandler().getActionURL(ctx, toUrl));

            extContext.redirect(url);
        } catch (IOException e) {
            throw new FacesException(e);
        }
    }