在Java中创建JSON对象的方法

Question

The following is the JSON body I want to use in my iOS (Swift) and Android (Java) applications.

{
    "type" : "select",
    "args" : {
        "table"  : "todo",
        "columns": ["id", "title","completed"],
        "where"  : {"user_id": 1}
    }
}

In Swift, it is pretty straightforward and easy to convert the above into a Dictionary :

let params: [String: Any] = [
  "type" : "select",
  "args" : [
    "table"     : "todo",
    "columns"   : ["id","title","completed"],
    "where"     : ["user_id" : 1]
  ]
]

In Java, I am using GSON to do the above, but I feel that my solution is ugly and too long

public class SelectQuery {

    @SerializedName("type")
    String type = "select";

    @SerializedName("args")
    Args args;

    public SelectTodoQuery(=) {
        args = new Args();
        args.where = new Where();
        args.where.userId = 1;
    }

    class Args {

        @SerializedName("table")
        String table = "todo";

        @SerializedName("columns")
        String[] columns = {
                "id","title","completed"
        };

        @SerializedName("where")
        Where where;

    }

    class Where {
        @SerializedName("user_id")
        Integer userId;
    }

}

Is there a better way to do this in Java and also how will one go about representing this JSON in Java natively, without the use of GSON?

UPDATE

I am not asking for a list of libraries which help me do the above, I already know of them and clearly am using one. I do not need to know about their performance either. I am asking for a better implementation (if it exists) and if Java does not provide such a feature, that can be an accepted answer too. Also, an example for doing the same natively in Java.

Answer 1

Well, there are several libs available to serialize and de-serialize object to and from json .

GSON is the simplest one, you can convert your POJO (plan old java object) to JSON without annotating them.

LoganSquare is the best library for this purpose, it requires you to annotate your fields but the performance is pretty high.

Github page actually tells about benchmark study of LoganSquare vs other options.

There are a few others like Moshi and Jackson but considering Platform's limitations I have found LoganSquare the best.

As far as Native capability is concerned, Java so far does not provide any such utility and if someone is not interested in Third partylibs , the project I have mentioned above are all open source objects, one can fork them and implement their own version based on one's usecases.

Answer 2

With Gson you can try something like this, i am not sure about the type you want to read here:

final GsonBuilder builder = new GsonBuilder();
final Gson gson = builder.enableComplexMapKeySerialization().create();
final Type type = new TypeToken<Map<String, Args>>(){}.getType();

// deserialize from a string (read your file to string maybe)
HashMap<String, Args> aMap = gson.fromJson(aJSONString, type);