gson-example

private final static String jsonUrl = "https://api.privatbank.ua/p24api/exchange_rates?json&date=01.04.2020";
private final static String path = "D:\\Programming\\java\\projects\\documents-parsing\\src\\resources\\json\\cats.json";
private final static String newFile = "D:\\Programming\\java\\projects\\documents-parsing\\src\\resources\\json\\catsFromGson.json";

GsonBuilder gsonBuilder = new GsonBuilder();

gsonBuilder.setPrettyPrinting();

Gson gson = gsonBuilder.create();

try {

  JsonReader jsonReader = new JsonReader(new InputStreamReader(new URL(jsonUrl).openStream()));
  Currency currency = gson.fromJson(jsonReader, Currency.class);
  System.out.println(currency.getBank());

  JsonReader jsonReader2 = new JsonReader(new FileReader(new File(path)));
  Cat[] cats = gson.fromJson(jsonReader2, Cat[].class);

            for (Cat cat: cats) {
                System.out.println(cat.getName());
            }

            String gsonString = gson.toJson(cats);

            System.out.println(gsonString);

            Files.write(Paths.get(newFile), gsonString.getBytes(), StandardOpenOption.CREATE);

            Cat[] cats1 =  gson.fromJson("[\n" +
                    "  {\n" +
                    "    \"name\": \"Murzik\",\n" +
                    "    \"age\": 7\n" +
                    "  },\n" +
                    "  {\n" +
                    "    \"name\": \"Pukh\",\n" +
                    "    \"age\": 8\n" +
                    "  }\n" +
                    "]", Cat[].class);
            for (Cat cat : cats1) {
                System.out.println(cat.getName());
            }