list.toArray();
Arrays.asList(arr);
String str = String.join(",", list);
+--------------------+ +------+ +------+ +---+ +-------+
| stream of elements +-----> |filter+-> |sorted+-> |map+-> |collect|
+--------------------+ +------+ +------+ +---+ +-------+
filter
filter(Objects::nonNull);// 过滤空元素
filter(u -> StringUtils.isNotEmpty(u.getId()))
sorted
sorted(Comparator.comparing(User::getHeight).reversed())
map
map(User::getId)
map(String::valueOf)
map(i -> i*i)
collect
collect(Collectors.toList())
collect(Collectors.joining(","));// 以","拼接各元素
collect(Collectors.toMap(User::getId, u -> u))
collect(Collectors.groupingBy(User::getCityId));// 无序分组
collect(Collectors.groupingBy(User::getCityId, LinkedHashMap::new, Collectors.toList()));// 有序分组
boolean = anyMatch(u -> u.getType() == 1)
boolean = noneMatch(u -> u.getType() == 1)
count()
distinct()
forEach()
findAny()
findFirst().ifPresent(x -> x)
mapToInt(x -> x).summaryStatistics();// 统计
taskList.removeIf(model -> model.getMachineId() == 25);
// 累计BigDecimal
.map(OrderModel::getPrice).reduce(BigDecimal.ZERO, BigDecimal::add)
