stream流常用方法

1.stream根据指定字段去重

List afterIndcatorList = indcatorList.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(RiskTemplateIndicatorCategory::getId))), ArrayList::new));

2.stream根据指定字段排序（默认正序排列，如果要倒序在后面加reverse即可）

analysisList = analysisList.stream().sorted(Comparator.comparing(RiskVo::getOneLevelId)).collect(Collectors.toList());

3.stream根据指定字段值过滤数据

List sysIndicate = analysisList.stream().filter(item -> StringUtils.equals("195", item.getOneLevelId())).collect(Collectors.toList());

4.stream根据指定字段值求平均

Double avg = mapRecords.stream().collect(Collectors.averagingDouble(riskRankForUnitVo -> Double.parseDouble(riskRankForUnitVo.getSafetyScore())));

5.stream根据指定字段值求最小值

double min = mapRecords.stream().collect(Collectors.summarizingDouble(riskRankForUnitVo -> Double.parseDouble(riskRankForUnitVo.getSafetyScore()))).getMin();

6.stream根据指定字段值排序取topN

List collect = noRepeatList.stream().sorted(Comparator.comparing(TRiskAssessRecord::getTotalScore)).limit(3).collect(Collectors.toList());