Gson Help - Trying to get the first value (key) of JSON using Gson

Question

Trying to get the fist value (key) of JSON using Gson lib, any help is good. Looking to get -K_63RGSCZra1jVeDrmT from the JSON and want to save it in String variable.

Here is mine code and output :

gson.toJson(dataSnapshot.getValue());
Log.d(tag, "gson: " + gson.toJson(dataSnapshot.getValue()));

output:

{"-K_63RGSCZra1jVeDrmT":{"name":"Joseph witman","email":"jwitman@gmail.com"}}

Answer 1

You could try

String json = "{\"-K_63RGSCZra1jVeDrmT\":{\"name\":\"Joseph witman\",\"email\":\"jwitman@gmail.com\"}}";
JsonParser jp = new JsonParser();
JsonElement element = jp.parse(json);
JsonObject root = element.getAsJsonObject();

Since JsonObject.entrySet() contains all key values you could extract them in the following way;

for (Entry<String, JsonElement> e : root.entrySet()) {
    System.out.println(e.getKey());
}

Answer 2

Here is your code to get key :

    JsonParser parser = new JsonParser();
    JsonObject jobj = parser.parse(new FileReader("Filepath_JSON")).getAsJsonObject();

    Gson gson = new Gson();
    Set<Map.Entry<String, JsonElement>> entrySet = jobj.entrySet();
    for(Map.Entry<String, JsonElement> entry : entrySet) {
        Person prsn = gson.fromJson(jobj.getAsJsonObject(entry.getKey()), Person.class);
        prsn.setId(entry.getKey());
        System.out.println("id :  " + prsn.getId());

    }

Here is Pojo Person class :

class Person {

private String id;
private String name;
private String email;


public String getId() {
    return id;
}
public void setId(String id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getEmail() {
    return email;
}
public void setEmail(String email) {
    this.email = email;
} }

I run the code and it works fine.

Cheers.