使用Spring Data Mongodb指定原始聚合请求

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.query.Criteria;

// 创建聚合操作
Aggregation aggregation = Aggregation.newAggregation(
    Aggregation.match(Criteria.where("age").gt(18)), // 过滤条件
    Aggregation.group("gender").count().as("count"), // 分组统计
    Aggregation.sort(Sort.Direction.DESC, "count"), // 排序
    Aggregation.project("gender", "count").andExclude("_id") // 投影字段
);

// 执行聚合操作
AggregationResults<ResultType> results = mongoTemplate.aggregate(aggregation, "collectionName", ResultType.class);

// 获取结果
List<ResultType> resultList = results.getMappedResults();