Java Time
兩時間相減
```java= ZonedDateTime k1t = ZonedDateTime.parse("2022-04-28T00:40:00+00:00"); ZonedDateTime k2t = ZonedDateTime.parse("2022-04-28T00:35:00+00:00"); double v= ChronoUnit.MILLIS.between( k1t,k2t) / 1000; System.out.println(v);
// -300.0 double v= ChronoUnit.MILLIS.between(k2t, k1t) / 1000; System.out.println(v); // 300.0
## +秒數
```java=
ZonedDateTime date = ZonedDateTime.parse("2017-03-28T12:25:38.492+05:30[Asia/Calcutta]");
System.out.println(date.plusSeconds(20));
plus by ChronoUnit
Instant instant
= Instant.parse("2018-12-30T19:34:50.63Z");
// add 30 DAYS to Instant
Instant value
= instant.plus(30, ChronoUnit.DAYS);
Timestamp to ZonedDateTime,LocalDateTime
```java=
import java.sql.Timestamp;
import java.time.LocalDateTime;
...
Timestamp timestamp = new Timestamp(System.currentTimeMillis());
Instant i= timestamp.toInstant();
ZonedDateTime ans = instant.atZone(
### ZonedDateTime to Date
```java!
Date.from(java.time.ZonedDateTime.now().toInstant());