[Java知识库]JAVA获取前N周的时间区间

    @ApiOperation("获取周时间的区间值")
    private void getWeekTimeSection(int weekIndex)
    {
        //weekIndex为前几周的周数，如：获取当前时间前第二周的时间 weekIndex=2
        //获取本周第一天
        Calendar cal=Calendar.getInstance();
        cal.add(Calendar.WEEK_OF_MONTH, 0);
        cal.set(Calendar.DAY_OF_WEEK, 2);
        Date first=cal.getTime();
        Date last=cal.getTime();
        String firstString= new SimpleDateFormat("yyyy-MM-dd").format(first)+" 00:00:00";
        String lastString= new SimpleDateFormat("yyyy-MM-dd").format(last)+" 23:59:59";
        LocalDateTime firstTime = LocalDateTime.parse(firstString, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        LocalDateTime lastTime = LocalDateTime.parse(lastString, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        firstTime=firstTime.plusDays(-(weekIndex* 7L)); //开始时间
        lastTime=lastTime.plusDays(-(weekIndex*7L-6)); //结束时间
    }

    @ApiOperation("获取当前时间")
    private String getDateByString() {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");//设置日期格式
        return  df.format(new Date());
    }