java - java.util 包和 java.sql 包中 Date 类的区别

Question

在java中，java.util和java.sql包中都包含一个Date类，那么它们有什么区别？

如果 Java 中存在一个 Date 类，那么还需要另一个 Date 类吗？

Answer 1

来自 the JavaDoc of java.sql.Date :

A thin wrapper around a millisecond value that allows JDBC to identify this as an SQL DATE value. A milliseconds value represents the number of milliseconds that have passed since January 1, 1970 00:00:00.000 GMT.

To conform with the definition of SQL DATE, the millisecond values wrapped by a java.sql.Date instance must be 'normalized' by setting the hours, minutes, seconds, and milliseconds to zero in the particular time zone with which the instance is associated.

说明:一个java.util.Date代表日期和时间，一个java.sql.Date只代表一个日期( java.sql.Date 的补码是 java.sql.Time ，它只表示一天中的某个时间，还扩展了 java.util.Date).