如何从年，月和日获取日期对象？

Question

When I used the following code, the Date Object was wrong.

Date date = new Date(day.getYear(), day.getMonth(), day.getDay());

Can anyone tell me how to get the Date Object From the value of year, month and day?

Answer 1

You can use the Calendar class to achieve this.

public static void main(String[] args) throws Exception {
    Date date = new Date (115, 7, 5);
    System.out.println("date     = " + date);

    Calendar calendar = GregorianCalendar.getInstance();
    calendar.set(Calendar.DAY_OF_MONTH, 5);
    calendar.set(Calendar.MONTH, 7);
    calendar.set(Calendar.YEAR, 2015);
    calendar.set(Calendar.MILLISECOND, 0);
    calendar.set(Calendar.SECOND, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    date = calendar.getTime();
    System.out.println("calendar = " + date);

    // or create directly a new clanedar instance
    // thanks Tom to mention this
    calendar = new GregorianCalendar(2015, 7, 5);
    date = calendar.getTime();
    System.out.println("calendar = " + date);
}

output

date     = Wed Aug 05 00:00:00 CEST 2015
calendar = Wed Aug 05 00:00:00 CEST 2015
calendar = Wed Aug 05 00:00:00 CEST 2015

Answer 2

Without knowing more I'd have to guess but probably you didn't read the JavaDoc on that deprecated constructor:

year the year minus 1900.
month the month between 0-11.
date the day of the month between 1-31.

As you can see, if you want to create a date for today (Aug 5th 2015) you'd need to use new Date (115, 7, 5);

If you see that documentation you are free to guess why this is deprecated and should not be used in any new code. :)

Answer 3

You can do it with a workaround if you're stuck to Java < 8, but it's very ugly:

java.util.Date date = new java.text.SimpleDateFormat("dd.MM.yyyy").parse("05.08.2015");

as @Thomas already stated, the default Constructor for date/month/year is deprecated. Probably take a look at this link if you have access to Java8.

Answer 4

您应该使用getDate（）而不是getDay（）方法来获取日期，因为getDay（）返回星期几而不是月份中的某天

Answer 5

• int getYear() Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.YEAR) - 1900.

• int getMonth() Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.MONTH).

• int getDay() Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.DAY_OF_WEEK).

Hence use :

Date date = new Date(Calendar.get(Calendar.YEAR) - 1900, Calendar.get(Calendar.MONTH), Calendar.get(Calendar.DAY_OF_WEEK));

Recomendation : Use Joda-Time