java 循环中使用list时，出现list中全部加入了对象导致没有实现分组的解决方案

清空list即可

    public List fetchNmapSingleTaskWithDataList() {
        Map map = new HashMap<>();
        List listNst = new ArrayList();
        List listNsp = new ArrayList();

        List<NmapSingleTaskWithBLOBs> nmapSingleTaskWithBLOBs = nmapSingleTaskMapper.selectByExampleWithBLOBs(null);
        List<NmapSingleipPortresultWithBLOBs> nmapSingleipPortresultWithBLOBs = this.getAll();

        for (NmapSingleTask nst :
                nmapSingleTaskWithBLOBs) {
            map.put("NmapSingleTask", nst);
            for (NmapSingleipPortresult nsp :
                    nmapSingleipPortresultWithBLOBs) {
                if (nst.getId().equals(nsp.getSingletaskid())) {
                    listNsp.add(nsp);
                }
            }
            map.put("NmapSingleipPortresults", listNsp);
            listNst.add(map);
//            清空map
            map = new HashMap();
//            清空list 如果不清空，listNsp会再次加入nsp，导致全部加进来了
            listNsp = new ArrayList();
        }

        return listNst;
    }