CODEWITHSUNDEEP
javajsonspring-bootgson
Bishnu Das
Bishnu Das

Reputation: 171

How to convert a java object to simple json string without converting the LocalDateTime field to an extended json object?

I need a help to convert a java object to json string without converting a LocalDateTime field to a separate object.

class MyObj {
 LocalDateTime date;
}

then,

MyObj dateObj = new MyObj();
dateObj.date = LocalDateTime.now();

When I am converting it to a json,

Gson gson = new GsonBuilder().setDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz").create();
gson.toJson(dateObj);

I am getting this:

 {
  "date": {
    "date": {
      "year": 2020,
      "month": 8,
      "day": 27
    },
    "time": {
      "hour": 8,
      "minute": 59,
      "second": 47,
      "nano": 0
    }
  }
}

But I want this:

"date" : "2020-08-27T08:59:470Z"

Kindly help me about it.

Upvotes: 0

Views: 1342

Answers (2)

Bishnu Das
Bishnu Das

Reputation: 171

I solved by this way.

Create a Gson object:

Gson gson = new GsonBuilder()
            .setPrettyPrinting()
            .registerTypeAdapter(LocalDate.class, new LocalDateAdapter())
            .create();

Use method like this:

String jsonRequestString = gson.toJson(request);

Create a serializer:

class LocalDateAdapter implements JsonSerializer<LocalDate> {

@Override
public JsonElement serialize(LocalDate date, java.lang.reflect.Type typeOfSrc, JsonSerializationContext context) {
    return new JsonPrimitive(date.format(DateTimeFormatter.ISO_LOCAL_DATE));
}
}

Upvotes: 1

Hemant Patel
Hemant Patel

Reputation: 3260

As per javadoc of setDateFormat

The date format will be used to serialize and deserialize {@link java.util.Date}, {@link java.sql.Timestamp} and {@link java.sql.Date}.

You need to register custom serializer for LocalDateTime.class

JsonSerializer<LocalDateTime> localDateTimeSerializer = (src, type, context) -> {
    String date = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss").format(src);
    // String date = DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(src);
    // String date = src.toString();
    return new JsonPrimitive(date);
};

Gson gson = new GsonBuilder().registerTypeAdapter(LocalDateTime.class, localDateTimeSerializer).create();
gson.toJson(dateObj);

Note: LocalDateTime doesn't store timezone information, so you can't actually use Z in your date format pattern.

Upvotes: 0

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