gsonによるjson操作

1.jsonコードの読み出しは以下の通りです.

public static void main(String[] args) {

    JsonParser parser = new JsonParser();
    try {
        JsonObject object = (JsonObject) parser.parse(new FileReader("test.json"));

        System.out.println("code = " + object.get("code").getAsInt());
        System.out.println("message = " + object.get("message").getAsString());

        JsonArray array = object.get("data").getAsJsonArray();
        for (int i = 0; i < array.size(); i++) {

            System.out.println("===========================");

            JsonObject subObject = array.get(i).getAsJsonObject();

            System.out.println("icon = " + subObject.get("icon").getAsString());
            System.out.println("name = " + subObject.get("name").getAsString());
            System.out.println("detail = " + subObject.get("detail").getAsString());
            System.out.println("ptid = " + subObject.get("ptid").getAsString());
            System.out.println("url = " + subObject.get("url").getAsString());

        }

    } catch (JsonIOException | JsonSyntaxException | FileNotFoundException e) {

        e.printStackTrace();
    }

}

2.jsonを作成します.コードは次のとおりです.public static void main(String[]args){

    JsonObject object = new JsonObject();
    object.addProperty("cat", "it");
    
    JsonArray array = new JsonArray();
    
    JsonObject lan1 = new JsonObject();
    lan1.addProperty("id", 1);
    lan1.addProperty("name", "Java");
    lan1.addProperty("ide", "Eclipse");
    array.add(lan1);
    
    JsonObject lan2 = new JsonObject();
    lan2.addProperty("id", 2);
    lan2.addProperty("name", "Swift");
    lan2.addProperty("ide", "Xcode");
    array.add(lan2);
    
    JsonObject lan3 = new JsonObject();
    lan3.addProperty("id", 3);
    lan3.addProperty("name", "C#");
    lan3.addProperty("ide", "Visual Studio");
    array.add(lan3);
    
    object.add("language", array);
    object.addProperty("pop", true);

    System.out.println(object.toString());
    
}