记录List集合根据对象的某个属性进行分组

利用Stream流

 List<PbmSupplierEvaluationDetail> scoreIndexSumList = pbmSupplierEvaluationDetailMapper.selectPbmSupplierEvaluationDetailList(scoreIndexSum);
        //根据不同的评价人(businessauthor)分组
Map<String, List<PbmSupplierEvaluationDetail>> resultData = scoreIndexSumList.stream().filter(MiddleDictData -> StringUtils.isNotBlank(MiddleDictData.getBusinessauthor()))
.collect(Collectors.groupingBy(PbmSupplierEvaluationDetail::getBusinessauthor));

记录：Double类型转BigDecimal

 double v = Double.parseDouble(er.getTechnologyapproval());
 BigDecimal bigDecimal = BigDecimal.valueOf(v);

记录：对集合中的某个属性的值进行累加计算

BigDecimal reduce = Optional.ofNullable(pbmSupplierEvaluationDetailsSum)
                        .orElse(new ArrayList<>())
                        .stream()
                        .filter(itemsum -> itemsum.getSumScore()!= null) // 避免空指针
        .map(PbmSupplierEvaluationDetail::getSumScore)//SumScore为需要进行累加计算的对象属性（注意:sumScore的字段属性必须为BigDecimal才能利用此工具类）
                        .reduce(BigDecimal.ZERO, BigDecimal::add);