Force GSON to create a constructor containing setters or setters instead of fields

Question

Let's say I have the following model class:

public class Product
{
    private int ProductId;
    private String Name;

    public Product(){
        setProductId(0);
        setName("");
    }

    // Getter and Setter for the Product-ID
    public void setProductId(int i){
        if(i >= 0) {
            ProductId = i;
        } else {
            ProductId = 0;
        }
    }
    public int getProductId(){
        return ProductId;
    }

    // Getter and Setter for the Name
    public void setName(String n){
        if(n != null && n.length() > 0) {
            name = n;
        } else {
            name = ""; 
        }
    }
    public String getName(){
        return name;
    }
}

The following Json-Strings:

"[{\"$id\":\"1\",\"ProductId\":1,\"Name\":\"A Product\"}," + 
"{\"$id\":\"2\",\"ProductId\":2,\"Name\":\"Another Product\"}]";

and

"[{\"$id\":\"1\",\"ProductId\":1,\"Name\":\"A Product\"}," + 
"{\"$id\":\"2\",\"ProductId\":-4,\"Name\":null}]";

And the following conversion method:

public void jsonToProducts(String json){
    ArrayList<Product> p = null;
    if(json != null && json.length() > 0){
        try{
            Type listType = new TypeToken<ArrayList<Product>>(){}.getType();
            p = new Gson().fromJson(json, listType);
        }
        catch(JsonParseException ex){
            ex.printStackTrace();
        }
    }
    setProducts(p);
}

By default, Gson uses fields. Because of this, I get the following results from two Json-Strings:

// Json-String 1:
Product 1: ProductId = 1; Name = "A Product";
Product 2: ProductId = 2; Name = "Another Product";

^ This is the result I want, so there is no problem.

// Json-String 2:
Product 1: ProductId = 1; Name = "A Product";
Product 2: ProductId = -4; Name = null;

^ This is not the result I want, because for the second product I want this instead:

Product 2: ProductId = 0; Name = "";

How to get Gson to use Setters instead?

I know how I can get Gson to use a constructor that has no parameters , but can I get Gson to use Setters? (Or, perhaps, a constructor with parameters, then I will just add another constructor, which received all the Model fields as parameters.)

Answer 1

Gson User Guide , . Getters Setters TODO/ ( 232).

( ):

public void jsonToProducts(String json){
    ArrayList<Product> products = null;
    if(json != null && json.length() > 0){
        try{
            Type listType = new TypeToken<ArrayList<Product>>(){}.getType();
            products = new Gson().fromJson(json, listType);
        }
        catch(JsonParseException ex){
            ex.printStackTrace();
        }
    }
    // TODO: Replace when Gson supports Setters or Parameterized Constructors
    if(products != null && products.size() > 0){
        for(Product p : products){
            p.setProductId(p.getProductId());
            p.setName(p.getName());
        }
    }

    setProducts(products);
}

. - Gson, . ( , 1250 , . , .)