java常用数据格式转化，类似数据库group by cube rollup

java常用数据格式转化，类似数据库group by cube rollup
单循环一条sql返回格式如：List<Map<String, List<Record>>>

List<Record> operationList = operationService.getByUserId(getCurrentUserId(), "qxpt");
List<Map<String, Object>> showList = new ArrayList<Map<String, Object>>();
List<Record> oList = null;//operationClass下的operation
Map<String, Object> classMap = new HashMap<String, Object>();
for (Record o : operationList) {
    if (!classMap.containsKey(o.getStr("class_name"))) {
        oList = new ArrayList<Record>();
        if (!classMap.isEmpty()) {
            showList.add(classMap);
        }
        classMap = new HashMap<String, Object>();
    }
    oList.add(o);
    classMap.put(o.getStr("class_name"), oList);//单循环持续更新oList
}
showList.add(classMap);

dataMap.put("showList", showList);
renderJson(dataMap);