Set MongoDb converter programmatically

Question

I'm trying to use a custom converter with spring-data-mongodb. I want to create it programmatically, but I get the following error:

org.springframework.core.convert.ConverterNotFoundException: No converter found capable of     converting from type org.joda.time.LocalDate to type java.lang.String
at org.springframework.core.convert.support.GenericConversionService.handleConverterNotFound(GenericConversionService.java:475)
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:175)
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:154)
....
....

The following is the failing code snippet:

    Mongo mongo = new Mongo();
    MongoDbFactory mongoDbFactory = new SimpleMongoDbFactory(mongo, "database");

    List<Converter> converters = new ArrayList<>();
    converters.add(new LocalDateWriteConverter());
    converters.add(new LocalDateReadConverter());
    CustomConversions customConversions = new CustomConversions(converters);

    MappingContext mappingContext = new SimpleMongoMappingContext();
    MappingMongoConverter mappingMongoConverter = new MappingMongoConverter(mongoDbFactory, mappingContext);
    mappingMongoConverter.setCustomConversions(customConversions);

    MongoTemplate mongoTemplate = new MongoTemplate(mongoDbFactory, mappingMongoConverter);

    MongoDbEvent mongoEvent = new MongoDbEvent(new LocalDate(2012, 12, 8));
    mongoTemplate.insert(mongoEvent);

And here are my converter classes:

class LocalDateReadConverter implements Converter<String, LocalDate> {
    @Override
    public LocalDate convert(String s) {
        // Conversion code omitted.
    }
}

class LocalDateWriteConverter implements Converter<LocalDate, String> {

    @Override
    public String convert(LocalDate localDate) {
        // Conversion code omitted.
    }
}

The class I'm trying to persist looks like this:

import org.joda.time.LocalDate;

public class MongoDbEvent {

    private String id;
    private LocalDate date;

    public MongoDbEvent(LocalDate date) {
        this.date = date;
    }

    public String getId() {
        return id;
    }

    public LocalDate getDate() {
        return date;
    }

    @Override
    public String toString() {
        return "MongoDbEvent{" +
                "id='" + id + '\'' +
                ", date=" + date +
                '}';
        }
}

Answer 1

With the introduction of the java.time package in java 8 I ran into a similar issue using the new LocalDate and LocalDateTime classes in the new package. This is how I solved it:

I wrote a converter for all 4 of these conversion options:

• DateToLocalDateTimeConverter
• DateToLocalDateConverter
• LocalDateTimeToDateConverter
• LocalDateToDateConverter

Here is an example

public class DateToLocalDateTimeConverter implements Converter<Date, LocalDateTime> {

    @Override 
    public LocalDateTime convert(Date source) { 
        return source == null ? null : LocalDateTime.ofInstant(source.toInstant(), ZoneId.systemDefault()); 
    }
}

Then by including this in the xml configuration for the mongodb connection I was able to work in java 8 dates with mongodb (remember to add all the converters):

<mongo:mapping-converter>
    <mongo:custom-converters>
        <mongo:converter>
            <bean class="package.DateToLocalDateTimeConverter" />
        </mongo:converter>
    </mongo:custom-converters>
</mongo:mapping-converter>

Answer 2

Since org.springframework.data:spring-data-commons:1.13.3.RELEASE, here's how to programmatically create a MongoTemplate with custom converters

public MongoTemplate mongoTemplate(String mongoUri) throws Exception {
    MongoDbFactory factory = new SimpleMongoDbFactory(new MongoClientURI(mongoUri));
    CustomConversions conversions = new CustomConversions(
            Arrays.asList(new FooWriteConverter(), new FooReadConverter()));
    MongoMappingContext mappingContext = new MongoMappingContext();
    DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
    MappingMongoConverter mongoConverter = new MappingMongoConverter(dbRefResolver, mappingContext);
    mongoConverter.setCustomConversions(conversions);
    mongoConverter.afterPropertiesSet();
    return new MongoTemplate(factory, mongoConverter);
}

The converters (implementation omitted)

class FooWriteConverter implements Converter<Foo, DBObject> { ... }
class FooReadConverter implements Converter<DBObject, Foo> { ... }

Answer 3

This answer may be a little late for the OP, but I just ran into the same problem today and found a solution...

To set it up programmatically, you need to call MongoMappingConverter.afterPropertiesSet() before you use it. I realized this from reading the code for MongoTemplate.getDefaultMongoConverter(MongoDbFactory).

Here's an example:

MappingMongoConverter converter = new MappingMongoConverter(mongoDbFactory, context);
converter.setTypeMapper(mapper);
converter.setCustomConversions(new CustomConversions(
        Arrays.asList(
                new TimeZoneReadConverter(),
                new TimeZoneWriteConverter()
        )
));
converter.afterPropertiesSet();
MongoTemplate template = new MongoTemplate(mongoDbFactory, converter);

Answer 4

Just a heads up. I was struggling with that problem on spring-data-mongodb 1.5.1.RELEASEusing Java Configuration. As some classes have changed, I'm posting my solution.

Add the following definition in your configuration class annotated with @Configuration:

@Bean
public Mongo mongo() throws Exception {
    MongoPropertiesResolver resolver = mongoResolver();
    return new MongoClient(resolver.getUrl());
}

@Bean
public MongoDbFactory mongoDbFactory() throws Exception {
    return new SimpleMongoDbFactory(mongo(), "database");
}

@Bean
public MongoTemplate mongoTemplate() throws Exception {
    return new MongoTemplate(mongoDbFactory(), mongoConverter());
}

@Bean
public CustomConversions customConversions() {
    List<Converter<?, ?>> converters = new ArrayList<Converter<?, ?>>();
    converters.add(new TimeZoneReadConverter());
    converters.add(new TimeZoneReadConverter());
    return new CustomConversions(converters);
}

@Bean
public MappingMongoConverter mongoConverter() throws Exception {
    MongoMappingContext mappingContext = new MongoMappingContext();
    DbRefResolver dbRefResolver = new DefaultDbRefResolver(mongoDbFactory());
    MappingMongoConverter mongoConverter = new MappingMongoConverter(dbRefResolver, mappingContext);
    mongoConverter.setCustomConversions(customConversions());
    return mongoConverter;
}

Answer 5

How to customize mongo with custom converters is decribed here in detail:

http://docs.spring.io/spring-data/mongodb/docs/current/reference/html/#mapping-configuration

I injected the default configuration values so i can benefit from the application.properties configuration settings.

  @Configuration
  public class MongoConfiguration extends AbstractMongoConfiguration {
    @Value("${spring.data.mongodb.database:test}")
    String database;

    @Value("${spring.data.mongodb.host:localhost}:${spring.data.mongodb.port:27017}")
    String host;

    @Override
    protected String getDatabaseName() {
      return database;
    }

    @Override
    public Mongo mongo() throws Exception {
      return new MongoClient(host);
    }

    @Bean
    @Override
    public CustomConversions customConversions() {
      List<Converter<?, ?>> converterList = new ArrayList<Converter<?, ?>>();
      converterList.add(new MongoColorWriter());
      converterList.add(new MongoColorReader());
      return new CustomConversions(converterList);
    }
  }

Answer 6

For me it was registering my converter as a reader instead of a writer. To fix that you need to add the @WritingConverter annotation to your converter class

@Component
@WritingConverter
public class NoteWriterConverter implements Converter<Note, DBObject> {

@Override
public DBObject convert(Note source) {
    DBObject obj = new BasicDBObject();

    obj.put("title", source.getTitle());
    obj.put("reviewDate", source.getReviewDate());

    obj.removeField("_class");
    return obj;
    }
}