转载自  Java 8 中 Date与LocalDateTime、LocalDate、LocalTime互转

Java 8中 java.util.Date 类新增了两个方法，分别是from(Instant instant)和toInstant()方法

// Obtains an instance of Date from an Instant object.
public static Date from(Instant instant) {try {return new Date(instant.toEpochMilli());} catch (ArithmeticException ex) {throw new IllegalArgumentException(ex);}
}// Converts this Date object to an Instant.
public Instant toInstant() {return Instant.ofEpochMilli(getTime());
}

这两个方法使我们可以方便的实现将旧的日期类转换为新的日期类，具体思路都是通过Instant当中介，然后通过Instant来创建LocalDateTime（这个类可以很容易获取LocalDate和LocalTime），新的日期类转旧的也是如此，将新的先转成LocalDateTime，然后获取Instant，接着转成Date，具体实现细节如下：

// 01. java.util.Date --> java.time.LocalDateTime
public void UDateToLocalDateTime() {java.util.Date date = new java.util.Date();Instant instant = date.toInstant();ZoneId zone = ZoneId.systemDefault();LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);
}// 02. java.util.Date --> java.time.LocalDate
public void UDateToLocalDate() {java.util.Date date = new java.util.Date();Instant instant = date.toInstant();ZoneId zone = ZoneId.systemDefault();LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);LocalDate localDate = localDateTime.toLocalDate();
}// 03. java.util.Date --> java.time.LocalTime
public void UDateToLocalTime() {java.util.Date date = new java.util.Date();Instant instant = date.toInstant();ZoneId zone = ZoneId.systemDefault();LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);LocalTime localTime = localDateTime.toLocalTime();
}// 04. java.time.LocalDateTime --> java.util.Date
public void LocalDateTimeToUdate() {LocalDateTime localDateTime = LocalDateTime.now();ZoneId zone = ZoneId.systemDefault();Instant instant = localDateTime.atZone(zone).toInstant();java.util.Date date = Date.from(instant);
}// 05. java.time.LocalDate --> java.util.Date
public void LocalDateToUdate() {LocalDate localDate = LocalDate.now();ZoneId zone = ZoneId.systemDefault();Instant instant = localDate.atStartOfDay().atZone(zone).toInstant();java.util.Date date = Date.from(instant);
}// 06. java.time.LocalTime --> java.util.Date
public void LocalTimeToUdate() {LocalTime localTime = LocalTime.now();LocalDate localDate = LocalDate.now();LocalDateTime localDateTime = LocalDateTime.of(localDate, localTime);ZoneId zone = ZoneId.systemDefault();Instant instant = localDateTime.atZone(zone).toInstant();java.util.Date date = Date.from(instant);
}