1.模糊查询

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@Override
 public List<Student> 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

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@Override



  public List<ClassRequest> 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<ClassRequest> aggregationResults =



              mongoTemplate.aggregate(aggregation, Student.class, ClassRequest.class);



 



      return aggregationResults.getMappedResults();



  }

3.分页聚合查询

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@Override



   public List<ClassRequest> 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<ClassRequest> aggregationResults =



               mongoTemplate.aggregate(aggregation, Student.class, ClassRequest.class);



       //获取结果集



       return aggregationResults.getMappedResults();



   }