Question

java中怎样计算两个日期之间的天数

Answer 1

/**
* 计算两个时间之间的差值，根据标志的不同而不同
*
* @param flag
* 计算标志，表示按照年/月/日/时/分/秒等计算
* @param calSrc
* 减数
* @param calDes
* 被减数
* @return 两个日期之间的差值
*/
public static int dateDiff(char flag, Calendar calSrc, Calendar calDes) {

long millisDiff = getMillis(calSrc) - getMillis(calDes);

if (flag == 'y') {
return (calSrc.get(calSrc.YEAR) - calDes.get(calDes.YEAR));
}

if (flag == 'd') {
return (int) (millisDiff / DAY_IN_MILLIS);
}

if (flag == 'h') {
return (int) (millisDiff / HOUR_IN_MILLIS);
}

if (flag == 'm') {
return (int) (millisDiff / MINUTE_IN_MILLIS);
}

if (flag == 's') {
return (int) (millisDiff / SECOND_IN_MILLIS);
}

return 0;
}

// 以毫秒表示的时间
private static final long DAY_IN_MILLIS = 24 * 3600 * 1000;
private static final long HOUR_IN_MILLIS = 3600 * 1000;
private static final long MINUTE_IN_MILLIS = 60 * 1000;
private static final long SECOND_IN_MILLIS = 1000;

参考代码，flag参数传入d就可以。