List<CourseRecord>转HashMap<Long, List<CourseRecord>>

HashMap<Long, List<CourseRecord>> recordMap = Maps.newHashMap();
        for (CourseRecord courseRecord : courseRecordList) {
            List<CourseRecord> recordList = Lists.newArrayList();
            if (recordMap.containsKey(courseRecord.getStudentId())) {
                recordList = recordMap.get(courseRecord.getStudentId());
            }
            recordList.add(courseRecord);
            recordMap.put(courseRecord.getStudentId(), recordList);
        }

结果：

{
    "code": 200,
    "success": true,
    "data": {
        "1310569218695020546": [
            {
                "id": "1310781082468171778",
                "courseId": "1310096960900935681",
                "studentId": "1310569218695020546",
                "age": 32,
                "height": 175,
                "weight": 70,
                "deviceId": 562830,
                "pushTime": "2020-09-29T11:18:58",
                "heartRate": 61,
                "isDeleted": 0
            },
            {
                "id": "1310781087014797314",
                "courseId": "1310096960900935681",
                "studentId": "1310569218695020546",
                "age": 32,
                "height": 175,
                "weight": 70,
                "deviceId": 562830,
                "pushTime": "2020-09-29T11:18:59",
                "heartRate": 62,
                "isDeleted": 0
            },
        ....
    }
}