Parsing Dates Gson: NumberFormatException

Question

I'm fairly new to java and Gson and I've been trying to parse some date from the nobelprize.org api. I've been able to parse through some of the info but when I include dates I seem to always hit errors. How would i go about fixing this error?

I've tried .setDateFormat("yyyy-MM-dd") but I still get the same error.

Gson mainparser = new GsonBuilder()
.setDateFormat("yyyy-MM-dd")
.create();

mainparser.fromJson(line, ParsedJson.class);

public class ParsedJson {

    List<Laureates> laureates;

    public List<Laureates> getLaureates() {
        return laureates;
    }

    public void setLaureates(List<Laureates> laureates) {
        this.laureates = laureates;
    }


}

public class Laureates {
    int id;
    String firstname;
    String surname;
    Date born;
    Date died;
    String bornCountry;
    String bornCountryCode;
    String bornCity;
    String diedCountry;
    String diedCountryCode;
    String diedCity;
    String gender;
    List<Prizes> prizes;
...Getters/Setters

}

This is the error I get:

java.lang.reflect.InvocationTargetException

Caused by: com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: For input string: "1845-03-27"

Caused by: java.lang.NumberFormatException: For input string: "1845-03-27"

*Edit: Example Json

    "laureates": [
        {
            "id": "1",
            "firstname": "Wilhelm Conrad",
            "surname": "Röntgen",
            "born": "1845-03-27",
            "died": "1923-02-10",
            "bornCountry": "Prussia (now Germany)",
            "bornCountryCode": "DE",
            "bornCity": "Lennep (now Remscheid)",
            "diedCountry": "Germany",
            "diedCountryCode": "DE",
            "diedCity": "Munich",
            "gender": "male",
            "prizes": [
                {
                    "year": "1901",
                    "category": "physics",
                    "share": "1",
                    "motivation": "\"in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him\"",
                    "affiliations": [
                        {
                            "name": "Munich University",
                            "city": "Munich",
                            "country": "Germany"
                        }
                    ]
                }
            ]
        },
]

Answer 1

You can try to use JsonDeserializer for Date attributes.

public class DateDeserializer implements JsonDeserializer<Date> {

   public DateDeserializer() {
   }

    @Override
    public Date deserialize(JsonElement element, Type arg1, JsonDeserializationContext arg2) throws JsonParseException {
        String dateStr = element.getAsString();
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd", Locale.getDefault());
        try {
            return format.parse(dateStr);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }
}

in your model class add JsonAdapter for attributes

public class Laureates {
    int id;
    String firstname;
    String surname;
    @JsonAdapter(DateDeserializer.class)
    Date born;
    @JsonAdapter(DateDeserializer.class)
    Date died;
    String bornCountry;
    String bornCountryCode;
    String bornCity;
    String diedCountry;
    String diedCountryCode;
    String diedCity;
    String gender;
    List<Prizes> prizes;
...Getters/Setters

}