jsf 2 - How to pass a List to javascript in JSF

Question

I am struggling with a JSF project. In my service, I retrieve a List of custom object (here Sales), and I have to pass it to my jsf view, specifically into the javascript, to make graphs.

My problem is, I don't understand how to send the data from the controller (my managed beans) to my view, and which tag to use in my view to retrieve it in my javascript.

I think I can pass my data like this, but I'm not sure

public String passData() {
    List<Sales> bestSelling = saleService.getBestSellingProduct(null, null, null, null);
    List<Sales> worstSelling = saleService.getWorstSellingProduct(null, null, null, null);

    FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("bestSelling", bestSelling);
    FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("worstSelling", worstSelling);

    return "./all.jsf?faces-redirect=true";
}

Answer 1

You need to create a JSON object that you'll assign to a JavaScript variable. To create JSON you may find useful to incorporate a library like Gson.

So, it'll look like:

var sales = #{bean.jsonList};

with Bean#getJsonList as:

public String getJsonList() {
     return (sales == null) ? "" : new Gson.toJson(sales);
}

Just don't forget that the script with such assignment must be handled by the FacesServlet.