将mongodb聚合查询转换为Java/Kotlin Spring数据

import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.aggregation.Aggregation;
import org.springframework.data.mongodb.core.aggregation.AggregationResults;
import org.springframework.data.mongodb.core.aggregation.TypedAggregation;
import org.springframework.data.mongodb.core.query.Criteria;

import java.util.List;

public class AggregationExample {
    private final MongoTemplate mongoTemplate;

    public AggregationExample(MongoTemplate mongoTemplate) {
        this.mongoTemplate = mongoTemplate;
    }

    public List<AggregationResult> performAggregation() {
        TypedAggregation<YourDocumentClass> aggregation = Aggregation.newAggregation(
                YourDocumentClass.class,
                Aggregation.match(Criteria.where("field").is("value")),
                Aggregation.group("field").count().as("count"),
                Aggregation.project("field", "count")
        );

        AggregationResults<AggregationResult> results = mongoTemplate.aggregate(aggregation, AggregationResult.class);
        return results.getMappedResults();
    }
}