Better way to handle my Json Load/Save?

Code:

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public static void saveTroops(String playerName, Troops troops)       
throws JsonGenerationException, JsonMappingException, IOException {
        final File playerFile = new File("./Data/json/militairy/Troops/" + playerName + ".json");
        final BufferedWriter writer = new BufferedWriter(new FileWriter(playerFile));
        if (!playerFile.exists())
                playerFile.createNewFile();

                writer.write(GSON.toJson(TROOPS.get(playerName)));
                writer.close();
                TROOPS.remove(playerName);
                loadTroops(playerName);
}

public static void loadTroops(String playerName) throws IOException {
        final JsonParser fileParser = new JsonParser();
        final Gson builder = new GsonBuilder().create();
        final File playerFile = new File("./Data/json/militairy/Troops/" + playerName + ".json");
        if (!playerFile.exists()) {
                playerFile.createNewFile();
                ObjectMapper mapper = new ObjectMapper();
                mapper.writeValue(playerFile, new Troops());
        }
        final JsonElement object = fileParser.parse(new FileReader(playerFile));
        final JsonElement reader = object;
        Troops objects = builder.fromJson(reader, Troops.class);
        TROOPS.put(playerName, objects);
}

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Is there a better way i can do this, maybe with less lines or something. I feel like this can be done better.

Yes, just use one API for parsing json. I recommend using only [Only registered and activated users can see links. Click Here To Register...] instead of mixing both Google Gson and Jackson API together.

You don't have to use JsonElement, JsonParser or even ObjectMapper mapper to achieve what you want to do.

Google Gson allows you to serialize all fields in an object that aren't transient.

Here's an example using Google Gson to serialize an array of objects.

Code:

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        public static void main(String[] args) throws IOException {

                // create the gson object and set json format property
                Gson gson = new GsonBuilder().setPrettyPrinting().create();
               
                // this list is used to create an array of objects
                List<Person> list = new ArrayList<>();
               
                // some object
                Person person = new Person(0, "free", Gender.MALE);
               
                Person person2 = new Person(1, "test", Gender.FEMALE);
               
                list.add(person);
                list.add(person2);
               
                // create json text from an array of objects
                String s = gson.toJson(list.stream().toArray(Person[]::new));
               
                // write the text to a file
                try (BufferedWriter writer = new BufferedWriter(new FileWriter(new File("./people.json")))) {
                        writer.write(s);
                }
               
        }

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Quick class for demonstration

Code:

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public class Person {
       
        // fields marked transient will not be serialized
        private final transient int id;
       
        private final String name;
       
        public final Gender gender;
       
        public Person(int id, String name, Gender gender) {
                this.id = id;
                this.name = name;
                this.gender = gender;
        }

        public int getId() {
                return id;
        }

        public String getName() {
                return name;
        }

        public Gender getGender() {
                return gender;
        }       

}

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Output

Code:

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[
  {
    "name": "free",
    "gender": "MALE"
  },
  {
    "name": "test",
    "gender": "FEMALE"
  }
]

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You can deserilize an array of objects like this

Code:

---

        public static void main(String[] args) throws IOException {
               
                List<Person> list = new ArrayList<>();
               
                Gson gson = new GsonBuilder().setPrettyPrinting().create();

                File file = new File("./people.json");
               
                if (!file.exists()) {
                        return;
                }
               
                try(BufferedReader reader = new BufferedReader(new FileReader(file))) {                       
                        list.addAll(Arrays.asList(gson.fromJson(reader, Person[].class)));
                }
               
                System.out.println("size: " + list.size());
               
                list.forEach(it -> {
                        System.out.println(it.getName() + " " + it.getGender().name() + "\n");
                });
               
        }

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Output

Code:

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size: 2
free MALE

test FEMALE

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Also don't ever do this on classes that implement Closeable, or else you'll have to manually close the stream. If you ever forgot to, than a resource leak will occur.

Code:

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final BufferedWriter writer = new BufferedWriter(new FileWriter(playerFile));

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A better practice is to use [Only registered and activated users can see links. Click Here To Register...] on classes that implement closeable. This will automatically close streams inside your try with resource block.

- Hope that helps