Cast json to hapi fhir object

Question

I have an appointment json which I need to cast to DSTU2 HAPI FHIR json object. Any standard library available for the same ? Google gson library works but does not give value to object in fields

{
  "resourceType": "Appointment",
  "id": "",
  "status": "proposed",
  "reason": {
    "text": "Regular checkup"
  },
  "description": "",
  "slot": [
    {
      "reference": "bfgf5dfdf4e45g"
    }
  ],
  "comment": "Regular yearly visit",
  "participant": [
    {
      "actor": {
        "reference": "9sdfsndjkfnksdfu3yyugbhjasbd"
      },
      "required": "required"
    },
    {
      "actor": {
        "reference": "78hjkdfgdfg223vg"
      },
      "required": "required"
    },
    {
      "actor": {
        "reference": "sdfs3df5sdfdfgdf"
      },
      "required": "required"
    }
  ]
}

Need to convert above json to ca.uhn.fhir.model.dstu2.resource.Appointment class for which I use

Appointment appointment = new Gson().fromJson(map.get("appointment"), Appointment.class);

but it gives appointment object with empty fields

What is the expected end result - to have an Appointment class with all fields populated? Then create the Appointment class and populate fields. It may take more than one line of code but at least you achieve what you need. — Shamil, Aug 03 '16 at 18:36

score 2 · Answer 1 · answered Aug 22 '16 at 15:02

You can just use the parser/serializer functionality built into HAPI:

String myJsonTxt = ""; // add your json here
FhirContext ctx = FhirContext.forDstu2();
Appointment app = (Appointment) ctx.newJsonParser().parseResource(myJsontxt);

Also, check your json, because in FHIR you do not add empty elements or properties.

score 2 · Accepted Answer · answered Nov 22 '16 at 07:00

Rather than using GSON directly, it's better to use HAPI FHIR api which internally uses GSON to parse the JSON. Maven dependency:

<dependency>
   <groupId>ca.uhn.hapi.fhir</groupId>
   <artifactId>hapi-fhir-base</artifactId>
   <version>2.1</version>
</dependency>
<dependency>
   <groupId>ca.uhn.hapi.fhir</groupId>
   <artifactId>hapi-fhir-structures-dstu3</artifactId>
   <version>2.1</version>
</dependency>

// More details on how to setup gradle and maven to get the HAPI fhir dependency added to your project please check http://hapifhir.io/download.html

Snippet:

FhirContext ourFhirCtx = FhirContext.forDstu3();
IParser parser=ourFhirCtx.newJsonParser().setPrettyPrint(true);
String string="{\"resourceType\":\"Appointment\",\"id\":\"\",\"status\":\"proposed\",\"reason\":{\"text\":\"Regular checkup\"},\"description\":\"\",\"slot\":[{\"reference\":\"bfgf5dfdf4e45g\"}],\"comment\":\"Regular yearly visit\",\"participant\":[{\"actor\":{\"reference\":\"9sdfsndjkfnksdfu3yyugbhjasbd\"},\"required\":\"required\"},{\"actor\":{\"reference\":\"78hjkdfgdfg223vg\"},\"required\":\"required\"},{\"actor\":{\"reference\":\"sdfs3df5sdfdfgdf\"},\"required\":\"required\"}]}";
Appointment parsed=parser.parseResource(Appointment.class,string);

Cast json to hapi fhir object

2 Answers2