如何使用GSON命名JSON对象数组？

Question

I'm using gson library and Mustach.js template engine. I'm passing Collection of Products to jsp page.

Now i'm using the following code:

Collection<Product> products = productDAO.findAll();
    Gson gson = new Gson();
    JsonElement element = gson.toJsonTree(products,
            new TypeToken<Collection<Product>>() {
            }.getType());
    JsonArray jsonArray = element.getAsJsonArray();
    HttpServletResponse response = ServletActionContext.getResponse();
    response.setContentType("application/json");
    response.setCharacterEncoding("UTF-8");
    PrintWriter writer = response.getWriter();
    writer.print(jsonArray);

it generates following json output:

[{"name":"Ut Nisi A PC","price":1133.43,"storeId":1,"id":2},
{"name":"Ipsum Dolor Sit Company","price":967.45,"storeId":1,"id":3},
{"name":"Ligula Limited","price":156.66,"storeId":1,"id":100}]

What I want is to name an array:

 {
    "products": 
    [{"name":"Ut Nisi A PC","price":1133.43,"storeId":1,"id":2},
    {"name":"Ipsum Dolor Sit Company","price":967.45,"storeId":1,"id":3},
    {"name":"Ligula Limited","price":156.66,"storeId":1,"id":100}]}

So then in jsp for Mustache.js template I can refer to array like:

   <div id="container"></div> 

    <script id="products-template" type="text/mustache-template">
        {{#products}}
            <li>{{name}},{{price}}</li>
        {{/products}}
    </script>
    $.ajax({
            type : 'GET',
            dataType : 'json',
            url : 'product/upload_products',
            success : function(products) {
                var template = $('#products-template').html();
                var info = Mustache.render(template, products);
                $('#container').html(info);
            }
        })
    </script>

How using GSON library such output can be achieved ?

Answer 1

Simply create a new JsonObject and add a field

JsonObject object = new JsonObject();
object.add("products", jsonArray);

then write that object to the response.

Answer 2

Use JsonObject. So,

JsonObject jsonObject = new JsonObject();
jsonObject.add("products", jsonArray); // jsonObject has the add method not put.

Answer 3

The key of a Json Object is always a String but the value can be a String, a boolean, a number, a json array, ....

If you have an object that is an array you only need to pass it to a jsonObject in the value and create a String key.

Manage the jsonObject like an HashMap. To do what you need make a put("products", yourJsonArrayObject) in a new Json Object.

JsonObject yourNewObject = new JsonObject();
yourNewObject.put("products", yourJsonArrayObject);