stream流式编程应用

1.构造连续日期

//2.构造连续的日期,对应图表的x轴
        Map<String, Object> collect = null;
        if (StringUtils.equals(vo.getType(), "1")) {
            //构造连续的日列表
            collect = new TreeMap<>(DateUtil.findDates(vo.getStartDate(), vo.getEndDate(), new SimpleDateFormat(format))
                    .stream()
                    .collect(Collectors.toMap(Function.identity(), s -> 0)));
        } else if (StringUtils.equals(vo.getType(), "2")) {
            //构造连续的周列表
            WeekFields weekFields = WeekFields.of(Locale.getDefault());
            int start = LocalDate.parse(vo.getStartDate()).get(weekFields.weekOfWeekBasedYear());
            int end = LocalDate.parse(vo.getEndDate()).get(weekFields.weekOfWeekBasedYear());
            collect = new TreeMap<>(IntStream.rangeClosed(start, end)
                    .mapToObj(s -> String.format("%02d", s))
                    .collect(Collectors.toMap(Function.identity(), s -> 0)));
        } else if (StringUtils.equals(vo.getType(), "3")) {
            //构造连续的月列表
            int start = LocalDate.parse(vo.getStartDate()).getMonthValue();
            int end = LocalDate.parse(vo.getEndDate()).getMonthValue();
            collect = new TreeMap<>(IntStream.rangeClosed(start, end)
                    .mapToObj(s -> String.format("%02d", s))
                    .collect(Collectors.toMap(Function.identity(), s -> 0)));
        }