Loop Json array with gson

Question

Im trying to parse a jsonObject and can't seem to get it, here is what i got.

 json = (json data)
 JsonParser parser = new JsonParser();
 JsonObject rootObj = parser.parse(json).getAsJsonObject();
 JsonObject paymentsObject = rootObj.getAsJsonObject("payments");

 for(JsonObject pa : paymentsObject){
        String dateEntered = pa.getAsJsonObject().get("date_entered").toString();
    }

But i get a foreach not applicable to type what am i missing. I've tried different ways but can't seem to get it. thanks

Json

 {
 "Name":"Test 2",
 "amountCollected":"1997",
 "payments":[
  {
     "quoteid":"96a064b9-3437-d536-fe12-56a9caf5d881",
     "date_entered":"2016-05-06 08:33:48",
     "amount":"1962",         
  },
  {
     "quoteid":"96a064b9-3437-d536-fe12-56a9caf5d881",
     "date_entered":"2016-05-06 08:33:08",
     "amount":"15",         
  },
  {
     "quoteid":"96a064b9-3437-d536-fe12-56a9caf5d881",
     "date_entered":"2016-05-06 03:19:08",
     "amount":"20",         
  }
 ]
}

JsonObject is not Iterable, so you cannot use it in an enhanced for loop like that. Maybe if you shared an example of the Json data you're trying to parse, we can better help you. One thought though: Are you sure the value of payments is an object, and not an array? Maybe you should have called rootObj.getAsJsonArray("payments"). The returned JsonArray is iterable. — Andreas
– Andreas, Commented May 25, 2016 at 3:20
I tried that and i get a com.google.gson.JsonObject cannot be cast to com.google.gson.JsonArray — user1054513
– user1054513, Commented May 25, 2016 at 3:24

Andreas · Accepted Answer · 2016-05-25 03:49:12Z

66

Now that we can see the data, we can see that payments is in fact an array (values uses []).

That means you need to call rootObj.getAsJsonArray("payments") which returns a JsonArray, and it is an Iterable<JsonElement>, which means your loop should be for(JsonElement pa : paymentsObject).

Remember, each value of the array can be any type of Json element (object, array, string, number, ...).

You know that they are JsonObject, so you can call getAsJsonObject() on them.

json = (json data)
JsonParser parser = new JsonParser();
JsonObject rootObj = parser.parse(json).getAsJsonObject();
JsonArray paymentsArray = rootObj.getAsJsonArray("payments");
for (JsonElement pa : paymentsArray) {
    JsonObject paymentObj = pa.getAsJsonObject();
    String     quoteid     = paymentObj.get("quoteid").getAsString();
    String     dateEntered = paymentObj.get("date_entered").getAsString();
    BigDecimal amount      = paymentObj.get("amount").getAsBigDecimal();
}

answered May 25, 2016 at 3:49

Andreas

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1 Comment

user1054513 Over a year ago

you are correct, i just noticed that sometimes my payments when a single value is a object not a array which is causing the error. Thanks you all for your help.

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