LookupOperation lookupOperation= LookupOperation.newLookup().from(AdminRepository.instance().getTableName()).  //关联从表名localField(User.Fields.name).     //主表关联字段foreignField(Admin.Fields.name).//从表关联的字段as("adminInfo");   //查询结果名Criteria left = Criteria.where(User.Fields.city).exists(true).andOperator(Criteria.where(User.Fields.age).gte(18),Criteria.where(User.Fields.age).lt(65));Criteria right = Criteria.where("adminInfo.0").exists(true).and("adminInfo.0.admin").is(1);GroupOperation group = Aggregation.group(User.Fields.city).first(User.Fields.age).as("firstAge").avg(User.Fields.age).as("avgAge").addToSet(User.Fields.age).as("ageList").count().as("count").max(User.Fields.age).as("maxAge").push(User.Fields.age).as("ageField");ProjectionOperation projectionOperation = Aggregation.project("_id").and("adult").applyCondition(ConditionalOperators.Cond.when(Criteria.where("firstAge").gt(12)).then(1).otherwise(0));Aggregation aggregation = Aggregation.newAggregation(Aggregation.match(left), lookupOperation,Aggregation.match(right),  Aggregation.unwind("adminInfo", true), group,projectionOperation);List<Map> results = this.getMongoOperations().aggregate(aggregation, this.getTableName(), Map.class).getMappedResults();

一、聚合

（1）匹配

Aggregation.match(left)

（2）分组

   GroupOperation group = Aggregation.group(User.Fields.city).first(User.Fields.age).as("age").avg(User.Fields.age).as("avgAge").addToSet(User.Fields.age).as("ageList").count().as("count").max(User.Fields.age).as("maxAge").push(User.Fields.age).as("ageField");

（3）投影

ProjectionOperation projectionOperation = Aggregation.project("_id").and("adult").applyCondition(ConditionalOperators.Cond.when(Criteria.where("firstAge").gt(12)).then(1).otherwise(0));

（4）扁平化数组

Aggregation.unwind("adminInfo", true)

二、连接

 LookupOperation lookupOperation= LookupOperation.newLookup().from(AdminRepository.instance().getTableName()).  //关联从表名localField(User.Fields.name).     //主表关联字段foreignField(Admin.Fields.name).//从表关联的字段as("adminInfo");   //查询结果名