Avro with Java 8 dates as logical type
You need to create your own Conversions to support java-8 date-time api, below is a conversion for java.time.LocalDate
:
class Java8LocalDateConversion extends Conversion<LocalDate> {
@Override
public Class<LocalDate> getConvertedType() {
return LocalDate.class;
}
@Override
public String getLogicalTypeName() {
// v--- reuse the logical type `date`
return "date";
}
@Override
// convert LocalDate to Integer
public Integer toInt(LocalDate value, Schema schema, LogicalType type) {
return (int) value.toEpochDay();
}
@Override
// parse LocalDate from Integer
public LocalDate fromInt(Integer value, Schema schema, LogicalType type) {
return LocalDate.ofEpochDay(value);
}
}
The logical types can be reused in avro, so you can using the existing date
logical type, for example:
Schema schema = LogicalTypes.date().addToSchema(Schema.create(Type.INT));
For the serializing & deserializing you should set the GenericData
which will find your own conversion, for example:
//serializing
DatumWriter<T> out = new SpecificDatumWriter<>(schema, data());
// deserializing
DatumReader<T> in = new SpecificDatumReader<>(schema, schema, data());
private SpecificData data() {
SpecificData it = new SpecificData();
it.addLogicalTypeConversion(new Java8LocalDateConversion());
return it;
}
If you don't want to configure the GenericData
every time, you can use the global GenericData
instead, for example:
// register the conversion globally ---v
SpecificData.get().addLogicalTypeConversion(new Java8LocalDateConversion());
- use Avro version >=
1.9.0
<1.10.0
- add
<dateTimeLogicalTypeImplementation>jsr310</dateTimeLogicalTypeImplementation>
intoconfiguration
section. - use Avro version >=
1.10.0
- java8/jsr310 native date/time classes used by default
Currently (avro 1.8.2) this is not possible. It's hardcoded to generate Joda date/time classes.
The current master
branch has switched to Java 8 and there is an open issue (with Pull Request) to add the ability to generate classes with java.time.*
types.
I have no idea on any kind of release schedule for whatever is currently in master
unfortunately. If you feel adventurous you can apply the patch to 1.8.2
, since in theory it should all be compatible. The underlying base types when serializing / deserializing are still integers and longs.