How to create indexes in MongoDB from Java

You can create indexes in MongoDB from Spring boot application using the following code:

import javax.annotation.PostConstruct;
import lombok.RequiredArgsConstructor;
import org.springframework.data.domain.Sort.Direction;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.index.Index;
import org.springframework.stereotype.Repository;

@Repository
@RequiredArgsConstructor
public class TestRepository {
    public static final String COLLECTION_NAME = "testCollection";

    private final MongoTemplate mongoTemplate;
    @PostConstruct
    private void initIndexes() {
            mongoTemplate.indexOps(COLLECTION_NAME).ensureIndex(new Index("fieldName", Direction.ASC).background());
    }

}

In this code MongoTemplate bean injected by spring as dependency. You also can use

MongoOperations

interface.

private final MongoTemplate mongoTemplate;

Function initIndexes() annotated as @PostConstruct will be run by Spring once on beanCreation. 1(source) 2(source)