记录一下java8 时间API与Date、long 之间的转换

• LocalDate -> long

// LocalDate -> long
LocalDate value = LocalDate.now();
long v = value.atStartOfDay(ZoneId.systemDefault()).toInstant().toEpochMilli();

• long -> LocalDate

// long -> LocalDate 
long value = 1645064099139L;
LocalDate v = LocalDateTime.ofInstant(Instant.ofEpochMilli(value), ZoneId.systemDefault()).toLocalDate();

• LocalDateTime -> long

// LocalDateTime -> Long
LocalDateTime value = LocalDateTime.now();
long v = value.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();

• long -> LocalDateTime

long value = 1645064099139L;
Instant instant = Instant.ofEpochMilli(value);
LocalDateTime v = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());

• long -> Date

long value = 1645064099139L;
Date d = new Date(value);

• Date -> long

Date d = new Date();
long value = d.getTime();