关于在java中,将Date型改成LocalDate型

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Short answer:

Date input = new Date();LocalDate date = input.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();

Explanation:

Despite its name, java.util.Date represents an instant on the time-line, not a "date". The actual data stored within the object is a long count of milliseconds since 1970-01-01T00:00Z (midnight at the start of 1970 GMT/UTC).

The equivalent class to java.util.Date in JSR-310 is Instant, thus there is a convenient method toInstant() to provide the conversion:

Date input = new Date();Instant instant = input.toInstant();

java.util.Date instance has no concept of time-zone. This might seem strange if you call toString() on a java.util.Date, because the toString is relative to a time-zone. However that method actually uses Java's default time-zone on the fly to provide the string. The time-zone is not part of the actual state of java.util.Date.

An Instant also does not contain any information about the time-zone. Thus, to convert from an Instant to a local date it is necessary to specify a time-zone. This might be the default zone - ZoneId.systemDefault() - or it might be a time-zone that your application controls, such as a time-zone from user preferences. Use the atZone() method to apply the time-zone:

Date input = new Date();Instant instant = input.toInstant();ZonedDateTime zdt = instant.atZone(ZoneId.systemDefault());

ZonedDateTime contains state consisting of the local date and time, time-zone and the offset from GMT/UTC. As such the date - LocalDate - can be easily extracted using toLocalDate():

Date input = new Date();Instant instant = input.toInstant();ZonedDateTime zdt = instant.atZone(ZoneId.systemDefault());LocalDate date = zdt.toLocalDate();
注:在jdk1.8中,调用toInstant()方法时会抛出错误,其实1.8中直接将Date对象调用toLocalDate()方法即可!
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