要實現匯出這樣的一個表頭

下面程式碼就是返回以上的表頭

仔細看

    private List<List<String>> getBaoHead(BaobiaoVO baobiaoVO){
        List<List<String>> head = new ArrayList<>();
        List<String> headerr = new ArrayList<>();
        headerr.add(baobiaoVO.getFirstField());
        head.add(headerr);
        
 
if (StringUtils.hasText(baobiaoVO.getSecondField())) {
            List<String> itemCodeHeader = new ArrayList<>();
            itemCodeHeader.add(baobiaoVO.getSecondField());
            head.add(itemCodeHeader);
        }
        Map<String,List<String>> map = new HashMap<>();
        List
 
<String> headChildList = new ArrayList<>();
        headChildList.add("專案數量");
        headChildList.add("專案金額（元）");
        headChildList.add("金額佔比");
        map.put("平均毛利（評審毛利率）",headChildList);
        map.forEach((k,v) -> {
            String deviceCategory = k;
            List<String> ls = v;
            ls.forEach(e 
 
-> {
                List<String> headChild = new ArrayList<>();
                headChild.add(deviceCategory);
                headChild.add(e);
                head.add(headChild);
            });
        });
        return head;
    }