一个mongo聚合数据的例子

mongo里每天会记录一些这样的数据，要把这些数据按照时间聚合。

function statisticsSchoolForTimes(nowtime) {
    db.getCollection('all').aggregate(
    [
        {$match:{"time":nowtime}},
        {
            $group:{
                _id:{"schoolId":"$schoolId","userRole":"$userRole"},
                provinceCode:{$first:"$provinceCode"},
                provinceValue:{$first:"$provinceValue"},
                cityValue:{$first:"$cityValue"},
                cityCode:{$first:"$cityCode"},
                countyCode:{$first:"$countyCode"},
                countyValue:{$first:"$countyValue"},
                schoolLevel:{$first:"$schoolLevel"},
                schoolName:{$first:"$schoolName"},
                schoolId:{$first:"$schoolId"},
                time:{$first:"$time"},
                userRole:{$first:"$userRole"}
            }
         }
    ]).forEach(function(x){
            var praiseNum=db.getCollection('all').find({"schoolId":x.schoolId,"time":x.time,"type":"praise","userRole":x.userRole}).count();
            var downloadNum=db.getCollection('all').find({"schoolId":x.schoolId,"time":x.time,"type":"download","userRole":x.userRole}).count();
            var collectionNum=db.getCollection('all').find({"schoolId":x.schoolId,"time":x.time,"type":             "collection","userRole":x.userRole}).count();
            var commentNum=db.getCollection('all').find({"schoolId":x.schoolId,"time":x.time,"type":"comment","userRole":x.userRole}).count();
            var browseNum=db.getCollection('all').find({"schoolId":x.schoolId,"time":x.time,"type":"browse","userRole":x.userRole}).count();
            db.getCollection('school').insert(x);
            db.getCollection('school').update({"schoolId":x.schoolId,"time":x.time,"userRole":x.userRole},{'$set': {'praiseNum': praiseNum,'downloadNum': downloadNum,'collectionNum': collectionNum,'commentNum': commentNum,'browseNum': browseNum}});
        })
}

java里面每天凌晨定时执行这个函数即可

    private static SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    
    public void run() {
        try {
        	System.out.println("开始数据统计聚合任务，时间为："+formatter.format(Calendar.getInstance().getTime()));
        	aggregate();
            System.out.println("结束数据统计聚合任务，时间为："+formatter.format(Calendar.getInstance().getTime()));
        } catch (Exception e) {
            System.out.println("-------------数据统计聚合任务发生异常--------------"+e.toString());
        }
    }

    public static void aggregate(){
    	System.out.println("开始数据统计聚合任务，时间为："+formatter.format(Calendar.getInstance().getTime()));
    	MongoUtils mu = new MongoUtils();
		MongoUtils.createMongoClient();
		DB db=mu.getDB(MongoUtils.DATABASE);
		String nowTime = new SimpleDateFormat("yyyy-MM-dd").format(new Date());
		db.eval("statisticsDistrictForTimes('"+nowTime+"')");
		db.eval("statisticsSchoolForTimes('"+nowTime+"')");
		mu.closeConnection();
        System.out.println("结束数据统计聚合任务，时间为："+formatter.format(Calendar.getInstance().getTime()));
    }