I have simple document with Java 8 date/time fields
@Document
public class Token {
private Instant createdAt;
...
}
that I want to persist with Spring Data MongoDB version 1.5. But fields of type java.time.Instant
could not be de-serialized correctly because MappingMongoConverter
lacks converters for java.time
classes.
In Spring 4 I found org.springframework.format.datetime.standard.DateTimeConverters
with different Converter
s including InstantToLongConverter
and LongToInstantConverter
declared as private static classes.
How can I configure MongoTemplate
to use them to map Instant
fields to longs?
I don't know if this is the best way but I added Java 8 Date/Time (JSR-310) types support to Spring Data MongoDB 1.5.0.RELEASE
like this:
First step. Add simple Spring Converter
s
public class InstantToLongConverter implements Converter<Instant, Long> { @Override public Long convert(Instant instant) { return instant.toEpochMilli(); } } public class LongToInstantConverter implements Converter<Long, Instant> { @Override public Instant convert(Long source) { return Instant.ofEpochMilli(source); } } public class LocalDateToStringConverter implements Converter<LocalDate, String> { @Override public String convert(LocalDate localDate) { return localDate.toString(); } } public class StringToLocalDateConverter implements Converter<String, LocalDate> { @Override public LocalDate convert(String source) { return LocalDate.parse(source); } }
Second step. Register these custom Converter
s with MappingMongoConverter
in your AbstractMongoConfiguration
implementation like this:
@Configuration @EnableMongoRepositories(basePackages = {"my.app.repository"}) public class MongoConfiguration extends AbstractMongoConfiguration { ... @Override public CustomConversions customConversions() { return new CustomConversions(Arrays.asList( new InstantToLongConverter(), new LongToInstantConverter(), new LocalDateToStringConverter(), new StringToLocalDateConverter())); } }
Now your document's Instant
fields will be persisted as long values and LocalDate
s as Strings.
@user882209 explained it all just perfectly.
Since Spring Data MongoDB 1.7 the support for JSR-310 has been added.
If application is backed by Spring Boot every version over 1.2.8 would contain it as well.
In a Spring Boot-ed app you can just do it the following:
@Configuration
public class MongoDbConfig {
@Autowired
private MongoDbFactory mongoDbFactory;
@Bean
public MongoTemplate mongoTemplate() {
MappingMongoConverter converter = new MappingMongoConverter(new DefaultDbRefResolver(mongoDbFactory),
new MongoMappingContext());
converter.setCustomConversions(new CustomConversions(Arrays.asList(...)));
return new MongoTemplate(mongoDbFactory, converter);
}
}
The following converters are provided by the class: 类提供以下转换器:
DateToLocalDateTimeConverter - LocalDateTimeToDateConverter DateToLocalDateConverter - LocalDateToDateConverter DateToLocalTimeConverter - LocalTimeToDateConverter DateToInstantConverter - InstantToDateConverter
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