jdk1.8的日常使用

梦里梦外; 2022-05-25 06:17 136阅读 0赞

List<Long> listIds = Arrays.asList(str.split(",")).stream().map(s -> Long.parseLong(s.trim())).collect(Collectors.toList());

List<Long> newSkuIdList = skuIdList.stream().distinct().skip((currentPage - 1) * pageSize).limit(pageSize).collect(Collectors.toList());

Map<Long, String> openIdMap = list.stream()
            .collect(Collectors.toMap(User::getUserId, User::getXcxOpenId));

这篇文章不错:

https://www.cnblogs.com/wenbronk/p/7300544.html

BigDecimal add = list.stream().map(User::getHeight).reduce(BigDecimal.ZERO, BigDecimal::add);

提取集合里的id集合：
    foodBasicList.stream()
            .map(FoodBasic::getId).collect(Collectors.toList())

集合转map：foodBasicList.stream().collect(Collectors.toMap(FoodCountModel::getId, FoodCountModel::getSoldCount))

BigDecimal yearSaleMoney = list.stream().filter(s -> s.getNum() == 0).collect(Collectors.toList()).get(0).getSaleMoney();

List<Long> newAddressList = addressList.stream().map(s -> Long.valueOf(s)).collect(Collectors.toList());

java8 list统计（求和、最大、最小、平均）:

[https://blog.csdn.net/baobaodehao1991/article/details/81332584][https_blog.csdn.net_baobaodehao1991_article_details_81332584]

//2.根据拼团商品的排序规则,排序商品
    sortList.stream().forEach(s -> foodBasicList.stream()
            .filter(y -> s.equals(String.valueOf(y.getId()))).forEach(f -> fBasicList.add(f)));
    //或者是下面的方法
    //        sortList.stream().forEach(item -> {
    //            foodBasicList.stream().forEach(y -> {
    //                if (Long.valueOf(item) == y.getId()) {
    //                    fBasicList.add(y);
    //                }
    //            });
    //        });JDK1.8对List指定字段进行排序：http://www.mamicode.com/info-detail-2356310.html

java.util.Objects.equals(k, "E")
    java.util.Objects.nonNull(map)

[https_blog.csdn.net_baobaodehao1991_article_details_81332584]: https://blog.csdn.net/baobaodehao1991/article/details/81332584