对象数组分组求和以及将数组按某个字段分组

[{
    "xh": "2022050601",
    "score": 2.17,
    "clzTitle": "springboot班级1",
    "targetid": 1,
    "nickName": "张同学",
    "tcourseId": 10,
    "targetTitle": "目标1",
    "clzId": 10,
    "id": 3889,
    "type": "作业",
    "userId": 113,
    "pjtype": 1
},...]
{"2022050601": {
    "xh": "2022050601",
    "nickName": "张同学",
    "clzTitle": "springboot班级1",
    "score": 37.27,
    "detail": [
        {
            "xh": "2022050601",
            "score": 2.17,
            "clzTitle": "springboot班级1",
            "targetid": 1,
            "nickName": "张同学",
            "tcourseId": 10,
            "targetTitle": "目标1",
            "clzId": 10,
            "id": 3889,
            "type": "作业",
            "userId": 113,
            "pjtype": 1
        },
        ...
    ]
}
// js分组求和
let stusum = {};
data.map(item=>{
if(!stusum[item.xh]){
stusum[item.xh] ={xh:item.xh, nickName:item.nickName, clzTitle: item.clzTitle, score: 0, detail: []};
}
stusum[item.xh].score += item.score;
stusum[item.xh].detail.push(item);
});


// 将List按某个字段分组，将分组的集合添加到分组后对象的children属性
groupByDeptId(rows = []) {
      // 使用了聚合分组
      let ids = rows.reduce((pre, cur) => {
        (pre[cur.deptId] = pre[cur.deptId] || []).push(cur);
        return pre;
      }, {});
      ids = ids || {};
      // 封装自己需要的对象
      let list = [];
      for (let i in ids) {
        list.push({ id: i, name: ids[i][0].deptName, children: ids[i] });
      }
      this.dataList = list;
      // console.log(list);
},

// java分组求和
Map<Object, BigDecimal> collect =
            scoreList.stream().collect(Collectors.groupingBy(item -> item.get("xh").toString(),
                Collectors.reducing(BigDecimal.ZERO, t -> (BigDecimal)t.get("score"), BigDecimal::add)));
{2022050601=37.2700, 2022050603=29.1000, 2022050606=23.3000, 2022050608=19.5000}

List<Map<String, Object>> scoreList = bizPjMutilscoreMapper.selectBizPjMutilscoreListByCourseid(courseid);
        List<Map<String, Object>> res = new ArrayList<Map<String, Object>>();
        Map<String, List<Map<String, Object>>> gs =
            scoreList.stream().collect(Collectors.groupingBy(e -> e.get("xh").toString()));
        gs.forEach((k, v) -> {
            Map<String, Object> tmp = new HashMap<String, Object>();
            // 按属性排序
            v.sort(Comparator.comparing(t -> Integer.valueOf(t.get("pjtype").toString())));
            Map<String, BigDecimal> s = v.stream().collect(Collectors.groupingBy(e -> e.get("xh").toString(),
                Collectors.reducing(BigDecimal.ZERO, t -> new BigDecimal(t.get("score").toString()), BigDecimal::add)));
            tmp.put("xh", k);
            tmp.put("nickName", v.get(0).get("nickName").toString());
            tmp.put("clzTitle", v.get(0).get("clzTitle").toString());
            tmp.put("score", s.get(k));
            tmp.put("detail", v);
            res.add(tmp);
        });

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