Mapping Configuration
Unless explicitly configured, an instance of MappingMongoConverter is created by default when you create a MongoTemplate. You can create your own instance of the MappingMongoConverter. Doing so lets you dictate where in the classpath your domain classes can be found, so that Spring Data MongoDB can extract metadata and construct indexes. Also, by creating your own instance, you can register Spring converters to map specific classes to and from the database.
You can configure the MappingMongoConverter as well as com.mongodb.MongoClient and MongoTemplate by using either Java-based or XML-based metadata. The following example uses Spring’s Java-based configuration:
@Configuration
public class GeoSpatialAppConfig extends AbstractMongoConfiguration {
@Bean
public MongoClient mongoClient() {
return new MongoClient("localhost");
}
@Override
public String getDatabaseName() {
return "database";
}
@Override
public String getMappingBasePackage() {
return "com.bigbank.domain";
}
// the following are optional
@Bean
@Override
public CustomConversions customConversions() throws Exception {
List<Converter<?, ?>> converterList = new ArrayList<Converter<?, ?>>();
converterList.add(new org.springframework.data.mongodb.test.PersonReadConverter());
converterList.add(new org.springframework.data.mongodb.test.PersonWriteConverter());
return new CustomConversions(converterList);
}
@Bean
public LoggingEventListener<MongoMappingEvent> mappingEventsListener() {
return new LoggingEventListener<MongoMappingEvent>();
}
}AbstractMongoConfiguration requires you to implement methods that define a com.mongodb.MongoClient as well as provide a database name. AbstractMongoConfiguration also has a method named getMappingBasePackage(…) that you can override to tell the converter where to scan for classes annotated with the @Document annotation.
You can add additional converters to the converter by overriding the customConversions method. Also shown in the preceding example is a LoggingEventListener, which logs MongoMappingEvent instances that are posted onto Spring’s ApplicationContextEvent infrastructure.
AbstractMongoConfiguration creates a MongoTemplate instance and registers it with the container under the name mongoTemplate.
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Spring’s MongoDB namespace lets you enable mapping functionality in XML, as the following example shows:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mongo="http://www.springframework.org/schema/data/mongo"
xsi:schemaLocation="http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/data/mongo http://www.springframework.org/schema/data/mongo/spring-mongo-1.0.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<!-- Default bean name is 'mongo' -->
<mongo:mongo-client host="localhost" port="27017"/>
<mongo:db-factory dbname="database" mongo-ref="mongoClient"/>
<!-- by default look for a Mongo object named 'mongo' - default name used for the converter is 'mappingConverter' -->
<mongo:mapping-converter base-package="com.bigbank.domain">
<mongo:custom-converters>
<mongo:converter ref="readConverter"/>
<mongo:converter>
<bean class="org.springframework.data.mongodb.test.PersonWriteConverter"/>
</mongo:converter>
</mongo:custom-converters>
</mongo:mapping-converter>
<bean id="readConverter" class="org.springframework.data.mongodb.test.PersonReadConverter"/>
<!-- set the mapping converter to be used by the MongoTemplate -->
<bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate">
<constructor-arg name="mongoDbFactory" ref="mongoDbFactory"/>
<constructor-arg name="mongoConverter" ref="mappingConverter"/>
</bean>
<bean class="org.springframework.data.mongodb.core.mapping.event.LoggingEventListener"/>
</beans>The base-package property tells it where to scan for classes annotated with the @org.springframework.data.mongodb.core.mapping.Document annotation.