Spring boot 整合 mongoDB 高级用法——模糊查询、分页、聚合、分页聚合排序查询

1.模糊查询

   @Override
    public List find(int num, String name, String college, String className, int age, short sex, String partner) {
        Query query = new Query();
        Criteria criteria =new Criteria();
        if(num!=0){
            criteria.and("num").is(num);
        }
        if(name!=null){
            criteria.and("name").regex("^.*"+name+".*$");
        }
        if(className!=null){
            criteria.and("className").is(className);
        }
        if(college!=null){
            criteria.and("college").is(college);
        }
        if(age!=0){
            criteria.and("age").is(age);
        }
        if (sex > 0 && sex < 3) {
            criteria.and("sex").is(sex);
        }
        if(partner!=null){
            criteria.and("partner").is(partner);
        }
        query.addCriteria(criteria);
        return mongoTemplate.find(query,Student.class);
    }

2.聚合查询

  @Override
    public List calculate() {
        //Aggregation.match为条件筛选操作
        //Aggregation.group为分组操作
        //Aggregation.project为选择结果字段操作
        Aggregation aggregation = Aggregation.newAggregation(Aggregation.match(Criteria.where("college").is("计算机学院")),
                Aggregation.group("className","college").count().as("count")
                        .max("age").as("max")
                        .min("age").as("min")
                ,Aggregation.project().and("className").as("name").andInclude("college","count","max","min")
        );
        AggregationResults aggregationResults =
                mongoTemplate.aggregate(aggregation, Student.class, ClassRequest.class);

        return aggregationResults.getMappedResults();
    }

3.分页聚合查询

 @Override
    public List findTop() {
        //条件筛选操作
        AggregationOperation matchOperation = Aggregation.match(Criteria.where("college").is("计算机学院"));
        //分组操作
        AggregationOperation groupOperation = Aggregation.group("className","college")
                .count().as("count")
                .max("age").as("max")
                .min("age").as("min");
        //选择字段操作
        AggregationOperation projectOperation = Aggregation.project().and("className").as("name").andInclude("college","count","max","min");
        //排序操作
        AggregationOperation sortOperation = Aggregation.sort(Sort.Direction.ASC,"name","college");
        //跳过条数
        AggregationOperation skigOperation = Aggregation.skip(2l);
        //选择条数
        AggregationOperation limitOperation =Aggregation.limit(1);
        //从左到右按顺序操作,注意顺序不一样结果会不一样
        //例如先排序后取条数，和先去条数后排序是完全不一样的意思
        Aggregation aggregation = Aggregation.newAggregation(matchOperation,groupOperation,projectOperation,
                    sortOperation,skigOperation,limitOperation);
        //查询
        AggregationResults aggregationResults =
                mongoTemplate.aggregate(aggregation, Student.class, ClassRequest.class);
        //获取结果集
        return aggregationResults.getMappedResults();
    }