加上此配置：
MongodbConfiguration.java
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.convert.DbRefResolver;
import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
import org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper;
import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
@Configuration
public class AppMongoConfig {
@Autowired private MongoDbFactory mongoDbFactory;
@Autowired private MongoMappingContext mongoMappingContext;
@Bean
public MappingMongoConverter mappingMongoConverter() {
DbRefResolver dbRefResolver = new DefaultDbRefResolver(mongoDbFactory);
MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, mongoMappingContext);
converter.setTypeMapper(new DefaultMongoTypeMapper(null));
return converter;
}
}