日期时间处理

1.获取常用日期、手动设置日期

	// 获取当前日期
	LocalDate currentDate = LocalDate.now();
	//转化为Date格式
	Date currentDate1 = java.sql.Date.valueOf(currentDate);
	// 获取上个月的日期
	LocalDate previousMonth = currentDate.minusMonths(1);
	
        
	// 获取年份和月份
	YearMonth lastMonthYearMonth = YearMonth.from(previousMonth );
	int lastMonthYear = lastMonthYearMonth.getYear();
	int lastMonthMonth = lastMonthYearMonth.getMonthValue();
	//或
	int year = previousMonth.getYear();
	int month = previousMonth.getMonthValue();
	//获取一个月最后一天
	int lastDayOfThisMonthDay = YearMonth.from(currentDate).atEndOfMonth().getDayOfMonth();
	//手动设置一个日期
	Date startDate = new Date(year- 1900, month , 1, 0, 0, 0);
	Date endDate = new Date(lastMonthYear - 1900, lastMonthMonth, lastDayOfThisMonthDay, 23, 59, 59);
	 

2.获取日期时间段列表

	List<Date> dateList = new ArrayList<>();
	dateList.add(currentDate1);
	// 获取当天至前90天的日期
	for (int i = 1; i <= 90; i++) {
	    LocalDate date = currentDate.minusDays(i);
	    Date javaDate = java.sql.Date.valueOf(date);
	    dateList.add(javaDate);
	}
	//截取日期时间段
	dateList.subList(1,90);

3.将数据库查询到的日期转换为固定字符串

	DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
	dateFormat.format(record.getClickDate());
	
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    String formattedDate = currentDate.format(formatter);

4.查询条件中查询与某个日期相等(DATE_FORMAT字段为Date类型，formattedDate为3.中转换后的字符串)

	LambdaQueryWrapper<FunctionClickRecord> queryWrapper = new LambdaQueryWrapper<>();
	queryWrapper.apply("DATE_FORMAT(click_date, '%Y-%m-%d') = {0}", formattedDate);

5.查询日期范围内数据（CreateDate字段为Date格式）

	LambdaQueryWrapper<PerformanceDetectionTaskAssignmentDetailsInfo> queryWrapper =Wrappers.lambdaQuery();
	queryWrapper.between(PerformanceDetectionTaskAssignmentDetailsInfo::getCreateDate,startDate,endDate);

5.获取缓存过期时间

/**
     * 根据往后推迟的时间返回过期时间戳
     *
     * @param addTime 比当前时间多少分钟后过期
     * @return
     */
    private static long getExpirationTime(Long addTime) {
        long minutesToAdd = addTime; // 增加**分钟
        LocalDateTime now = LocalDateTime.now();
        LocalDateTime futureDateTime = now.plus(minutesToAdd, ChronoUnit.MINUTES);
        // 获取将来时间的时间戳（以秒为单位）
        long futureTimestampInSeconds = futureDateTime.toEpochSecond(java.time.ZoneOffset.UTC);
        return futureTimestampInSeconds;
    }

6.时间戳转为日期字符串输出

	SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
	//时间戳转换为时间
	long time = projectStateRecord.getGmtModified().getTime();
	Date date = new Date(time);
	returnReasonVO.setBackDate(sdf.format(date));