Distinct in Spring Data MongoDB

Question

Has anyone tried incorporating distinct in their query using Spring Data for Mongo. If you have an example can you please post it. Where and how sh

Answer 1

My environment: spring-data-mongodb 2.0.5,jdk1.8,

Here is my code sample:

import com.mongodb.client.DistinctIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.stereotype.Repository;
import java.util.ArrayList;
import java.util.List;


public List queryAllCategory() {
    List categoryList = new ArrayList<>();
    MongoCollection mongoCollection = mongoTemplate.getCollection("lexicon");
    DistinctIterable distinctIterable = mongoCollection.distinct("category",String.class);
    MongoCursor cursor = distinctIterable.iterator();
    while (cursor.hasNext()) {
        String category = (String)cursor.next();
        categoryList.add(category);
    }
    return categoryList;
}

about distinct method,please read: http://mongodb.github.io/mongo-java-driver/3.7/javadoc/com/mongodb/client/MongoCollection.html#distinct-java.lang.String-java.lang.Class-