Json mapper converts LocalDate to month, year, day of month etc - json

Question

Json mapper converts LocalDate to month, year, day of month ... when converting java class to json like this,
"dob":{
"year": 1992,
"month": "MARCH",
"dayOfMonth": 19,
"dayOfWeek": "THURSDAY",
"era": "CE",
"dayOfYear": 79,
"leapYear": true,
"monthValue": 3,
"chronology": {
"calendarType": "iso8601",
"id": "ISO"
}
}
this is saved as a Date in mysql as 1992-03-19 how to return this date as it is like
"dob:1992-03-19"

Answer 1

Jackson and java.time types
The Jackson JavaTimeModule is used to handle java.time serialization and deserialization.
It provides a set of serializers and deserializers for the java.time types. If the SerializationFeature.WRITE_DATES_AS_TIMESTAMPS is disabled, java.time types will be serialized in standard ISO-8601 string representations.
Handling serialization in your particular format
However, once you have a very particular format, you can create a custom serializer:
public class DateOfBirthSerializer extends JsonSerializer<LocalDate> {
#Override
public void serialize(LocalDate value, JsonGenerator gen,
SerializerProvider serializers) throws IOException {
gen.writeString("dob:" + value.format(DateTimeFormatter.ISO_DATE));
}
}
Then you can use it as follows:
public class Foo {
#JsonSerialize(using = DateOfBirthSerializer.class)
private LocalDate dateOfBirth;
// Getters and setters
}
Alternatively you can use:
SimpleModule module = new SimpleModule();
module.addSerializer(LocalDate.class, new DateOfBirthSerializer());
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(module);
It will be applied to all LocalDate instances serialized with that ObjectMapper.
Handling deserialization in your particular format
For deserialization, you can use something like:
public class DateOfBirthDeserializer extends JsonDeserializer<LocalDate> {
#Override
public LocalDate deserialize(JsonParser p,
DeserializationContext ctxt) throws IOException {
String value = p.getValueAsString();
if (value.startsWith("dob:")) {
value = value.substring(4);
} else {
throw ctxt.weirdStringException(value,
LocalDate.class, "Value doesn't start with \"dob:\"");
}
return LocalDate.parse(value, DateTimeFormatter.ISO_DATE);
}
}