CODEWITHSUNDEEP
javagson
Michael Blala
Michael Blala

Reputation: 51

get Item's value from json file using Gson

Here i have a little trouble with getting item's value from a JSON string using Gson.

First of all the first part of my code is to get an obejct from massive:

String jsonOutput= weatherDataCollect(message);
        Gson gson = new Gson();
        JsonElement element = gson.fromJson(jsonOutput, JsonElement.class);
        JsonObject jsonObject = element.getAsJsonObject();
        System.out.println(jsonObject.toString());
        JsonArray list = jsonObject.getAsJsonArray("list");

So now if I write:

JsonElement todaysWeather = list.get(0);

I get exactly what I need - this part of json

{"dt":1549281600,"main":{"temp":-0.38,"temp_min":-1.3,"temp_max":-0.38,"pressure":1024.85,"sea_level":1027.5,"grnd_level":1024.85,"humidity":94,"temp_kf":0.91},"weather":[{"id":600,"main":"Snow","description":"небольшой снегопад","icon":"13d"}],"clouds":{"all":92},"wind":{"speed":2.11,"deg":271.5},"snow":{"3h":0.5445},"sys":{"pod":"d"},"dt_txt":"2019-02-04 12:00:00"}

In JSON massive a lot of parts like this. From everyone I need to get value like this 1549281600 and compare with my to find out which one is closer.

The first part of code shoud look like this

        long tomorrowTime = getTomorrowUnixTime();
        long timeDifference = Integer.MAX_VALUE;
        int minDtIndex = 0; 
    for (int i = 0; i < list.size(); i++){
   JsonElement weatherItem = list.get(i);
   Integer dt = Integer.valueOf(weatherItem.getAsString("dt").toString());
                }

But this part Integer dt = Integer.valueOf(weatherItem.getAsString("dt").toString()) doesnt work. It should get values from every dt and compate to tomorrowTime

The second part will look like this:

long diff = Math.abs(tomorrowTime - dt);
if(diff < timeDifference){
timeDifference = diff;
minDtIndex = i;

Upvotes: 1

Views: 661

Answers (1)

Bakar
Bakar

Reputation: 433

Integer dt = Integer.valueOf(weatherItem.getAsString("dt").toString());

In this line, you are going to get the following compilation error: 

getAsString( ) 
in JsonElement cannot be applied

This is because the getAsString() doesn't not accept any parameters, this is your Syntax Error here.

Semantically you have first have interpret the JSON Element as JSON Object, once it's a JSON Object then you can extract your property named dt.

The way to do that is:

Integer dt = new Integer(weatherItem.getAsJsonObject().get("dt").getAsInt());

I'll reference this Question and to read about the JSON format itself on W3-Schools

The Rest you can manage on your own logic and coding :) Happy Coding!

Upvotes: 1

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