Pojo for Json if Pojo has built-in objects

Question

I have two POJO classes: AddressInformationand PackageInformation(with their getters and setters that are not listed in the code below).

public class AddressInformation {
    private Integer address_id;
    private String street_name;
    private String city;
    private String state;
    private Integer zipcode;
}

public class PackageInformation {

    private Integer packageId;
    private Integer packageType;
    private Double packageWeight;
    private AddressInformation packageSource;
    private AddressInformation packageDestination;
}

I am saving instances of classes using hibernate and trying to get the contents PackageInformationfrom the database using sleep mode and return the contents in JSON format. I do not use any frameworks.

    Session session = HibernateUtils.getSessionFactory().openSession();
    List<PackageInformation> packagelist = null;
    tx = session.beginTransaction();
    packagelist = session.createQuery("FROM PackageInformation").list();
    tx.commit();
    session.close();

I need packagelistone that has a PackageInformation set to convert to JSON.

The trap is that the object PackageInformationhas address information built into it.

I tried the code below to convert the PackageInformation collection to JSON:

JSONArray json = new JSONArray();
    Gson gson = new Gson();
    try{
        for(PackageInformation pack : packagelist){

            JSONObject jsonObj = new JSONObject();
            AddressInformation sourceAddress = pack.getPackageSource();
            JsonElement sourceAddressJson =  gson.toJsonTree(sourceAddress);
            jsonObj.put("sourceAddress",sourceAddressJson);
            AddressInformation destinationAddress = pack.getPackageDestination();
            JsonElement destinationeAddressJson =  gson.toJsonTree(destinationAddress);
            jsonObj.put("destinationAddress",destinationeAddressJson);
            jsonObj.put("package_id",pack.getPackageId());
            jsonObj.put("package_type",pack.getPackageType());
            jsonObj.put("package_weight",pack.getPackageWeight());
         }
        returnString = json.toString();
    }catch(JSONException je){
            returnString = je.toString();
    }
    return Response.status(200).entity(returnString).build();

JSON sourceAddress destinationAddress , JSON. : sourceAddress destinationAddress , JSON .

 [
  {
   "sourceAddress": {},
   "destinationAddress: {},
   "package_id": 1,
   "package_type": 1,
   "package_weight": 500,
  }
  {
   "sourceAddress": {},
   "destinationAddress: {},
   "package_id": 2,
   "package_type": 5,
   "package_weight": 700,
  }
 ] 

Answer 1

, , AddressInformation ( , ), .

-, . JsonElement JsonObject, " " , Gson.

, , JSON. .

public class PackageInformation {

    @SerializedName("package_id")
    Integer packageId;

    @SerializedName("package_type")
    Integer packageType;

    @SerializedName("package_weight")
    Double packageWeight;

    @SerializedName("sourceAddress")
    AddressInformation packageSource;

    @SerializedName("destinationAddress")
    AddressInformation packageDestination;
}

, @SerializedName, ( , , ). , Gson.

public class Q19615935 {

    public static void main(String[] args) {
       List<PackageInformation> list = new ArrayList<PackageInformation>();

       PackageInformation pi = new PackageInformation();
       pi.packageId = 42;
       pi.packageType = 21;
       pi.packageWeight = 2000.0;

       AddressInformation source = new AddressInformation();
       source.address_id = 1;
       source.city="A city";
       source.state="A state";
       source.street_name="A street name";
       source.zipcode=0;

       pi.packageSource= source;
       pi.packageDestination=new AddressInformation();

       list.add(pi);

       Gson g = new Gson();
       System.out.println(g.toJson(list));


    }

}

db, , ( ):

[
    {
        "package_id": 42, 
        "package_type": 21, 
        "package_weight": 2000, 
        "sourceAddress": {
            "address_id": 1, 
            "street_name": "A street name", 
            "city": "A city", 
            "state": "A state", 
            "zipcode": 0
        }, 
        "destinationAddress": { }
    }
]

:

• , .
• , , db , 1.