获取List中的最大、最小、平均值

Double max = doubleList.stream().max(Comparator.comparingDouble(Double::doubleValue)).orElse(null);
Double min = doubleList.stream().min(Comparator.comparingDouble(Double::doubleValue)).orElse(null);

Double max = doubleList.stream().mapToDouble(Double::doubleValue).max().getAsDouble();
Double min = doubleList.stream().mapToDouble(Double::doubleValue).min().getAsDouble();

Double avg = doubleList.stream().mapToDouble(Double::doubleValue).average().getAsDouble();

Double sum = doubleList.stream().mapToDouble(Double::doubleValue).sum();