JAVA8的一些写法

 sum求和

   int nostartNum = 0, proceNum = 0, doneNum = 0, delayNum = 0;
if (tasks != null) {
    // 创建时间在本周，状态为待处理
    nostartNum = tasks.stream().filter(task -> Func.equals(task.getStatus(), CommonConstant.task_status.created) && task.getCreateTime() != null && task.getCreateTime() > start && task.getCreateTime() < end).mapToInt(task -> 1).sum();
     // 创建时间在本周，状态为进行中
     proceNum = tasks.stream().filter(task -> Func.equals(task.getStatus(), CommonConstant.task_status.processing) && task.getCreateTime() != null && task.getCreateTime() > start && task.getCreateTime() < end).mapToInt(task -> 1).sum();
      // 完成时间在本周，状态为已完成
      doneNum = tasks.stream().filter(task -> Func.equals(task.getStatus(), CommonConstant.task_status.finished) && task.getDoneTime() != null && task.getDoneTime() > start && task.getDoneTime() < end).mapToInt(task -> 1).sum();
       //到期时间在本周，状态为进行中或待处理
      delayNum = tasks.stream().filter(task -> Stream.of(CommonConstant.task_status.created, CommonConstant.task_status.processing).collect(Collectors.toList()).contains(task.getStatus()) && task.getDueTime() != null && task.getDueTime() <= end).mapToInt(task -> 1).sum();
                    }

filter过滤

      Map priceMap = staffs.stream().map(staff -> {
            DeptTitle title = titleMap.get(staff.getTitle());
            if (title != null) title.setId(staff.getId());
            return title;
        }).filter(Objects::nonNull).collect(Collectors.toMap(DeptTitle::getId, DeptTitle::getUnitprice));


 Map map = children.stream()
                    .filter(Objects::nonNull)
                    .filter(task -> StringUtil.isNoneBlank(task.getPersonId()))
                    .filter(task -> task.getStartTime() != null)
                    .collect(Collectors.toMap(ProjectTask::getPersonId, ProjectTask::getStartTime, Math::min));