How to parse complex Json response file in Java

Suparna Das — Tue, 20 Oct 2020 16:59:06 +0000

Parsing of JSON file may get bit complicated and confusing if you are not sure which library to use. There are different ways and Implementation available however I chose to use GSON library since it looked feasible for the JSON file which I was trying to parse. Sample JSON is provided below

In this example, I have saved my response in a file for demonstration.
Objective: Get the value of PatientID from this JSON

{
  "response": {
    "body": {
      "patients": {
        "patient": [
          {
            "patientID": "ALM22346789",
            "submittedStatus": "In Progress",
            "patientType": "Inpatient",
            "submissionDate": "2020-10-15"
          }
        ]
      }
    },
    "status": {
      "statusCode": "200",
      "statusMessage": {

      }
    }
  }
}

Imports used:
import com.google.gson.JsonArray;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

Step1:
Read the file from the saved location and store it in JsonObject

JsonObject myobject = (JsonObject) new JsonParser().parse(new FileReader("MyFilePath"));

Step2: Hold the "response" in a JSON Object

JsonObject response = (JsonObject) myobject.get("response");

Step3: Drill down further and store the "body" and "patient" in JSON Object

JsonObject body = (JsonObject) response.get("body");
JsonObject patients= (JsonObject) body.get("patients");

Step4: "patient" tag is in a Array hence we will store it in Array Object

JsonArray patientbody= (JsonObject) patients.get("patient");
JsonObject patient0= patientbody.get(0).getAsJsonObject();

Step5: Next we will fetch the "patientID"

String patientID =caseBody0.get("patientID").getAsString(); System.out.println(patientID);

OutPut: (as printed in console)

ALM22346789

DEV Community: Suparna Das

How to parse complex Json response file in Java