日期时间库

Question

我试图用java制作一个简单的程序用户将输入他的生日并且app给了他约会这是我的代码

import java.util.*;

public class DOW {
public static void main(String [] args){
    Scanner scn = new Scanner(System.in);
    System.out.println("Enter Your Birthdate");
    System.out.print("Day : ");
    int day = scn.nextInt();
    System.out.print("Month : ");
    int month = scn.nextInt();
    System.out.print("Year : ");
    int year = scn.nextInt();
    scn.close();

    Calendar cal = Calendar.getInstance();
    cal.set(year, month-1, day);
    int dow = cal.get(Calendar.DAY_OF_WEEK);
    switch (dow){   
    case 1:
            System.out.println("Your Birthdate : " + "Sunday - " + day + "/" + month + "/" + year);
            break;
        case 2:
        System.out.println("Your Birthdate : " + "Monday - " + day + "/" + month + "/" + year);
        break;
        case 3:
        System.out.println("Your Birthdate : " + "Tuesday - " + day + "/" + month + "/" + year);
        break;
        case 4:
        System.out.println("Your Birthdate : " + "Wednesday - " + day + "/" + month + "/" + year);
        break;
        case 5:
        System.out.println("Your Birthdate : " + "Thursday - " + day + "/" + month + "/" + year);
        break;
        case 6:
        System.out.println("Your Birthdate : " + "Friday - " + day + "/" + month + "/" + year);
        break;
        case 7:
        System.out.println("Your Birthdate : " + "Saturday - " + day + "/" + month + "/" + year);
        break;
    }
}
}

但日期名称不正确，例如我的生日是18/1/1987它是星期天我的代码的结果是星期四

N.B int month2 = month1-1; 我写这个是因为java中的月份从0开始而不是1

所以任何帮助??

Answer 1

因为Calender.set按顺序要求参数：

public final void set(int year, int month, int date);

你的订单错了。将其更改为：

cal.set(year, month2, day);

您将获得正确的结果。

Answer 2

我认为代码有一些错误; cal.set(year, day, month2);不得按此顺序排列。

public final void set(int year,int month,int date)

是订单。

您设置错误，请执行cal.set(year,month2,day);。

Answer 3

工作代码：

import java.util.*;

public class DOW
{
    public static void main(String[] args)
    {
        Scanner scn = new Scanner(System.in);
        System.out.println("Enter Your Birthdate");
        System.out.print("Day : ");
        int day = scn.nextInt();
        System.out.print("Month : ");
        int month = scn.nextInt();
        System.out.print("Year : ");
        int year = scn.nextInt();
        scn.close();

        Calendar cal = Calendar.getInstance();
        cal.set(year, month-1, day);
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.MONDAY)
        {
            System.out.println("Your Birthdate : " + "Monday - " + day + "/" + month + "/" + year);
        }
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.TUESDAY)
        {
            System.out.println("Your Birthdate : " + "Tuesday - " + day + "/" + month + "/" + year);
        }
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.WEDNESDAY)
        {
            System.out.println("Your Birthdate : " + "Wednesday - " + day + "/" + month + "/" + year);
        }
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.THURSDAY)
        {
            System.out.println("Your Birthdate : " + "Thursday - " + day + "/" + month + "/" + year);
        }
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.FRIDAY)
        {
            System.out.println("Your Birthdate : " + "Friday - " + day + "/" + month + "/" + year);
        }
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY)
        {
            System.out.println("Your Birthdate : " + "Thursday - " + day + "/" + month + "/" + year);
        }
        if (cal.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY)
        {
            System.out.println("Your Birthdate : " + "Sunday - " + day + "/" + month + "/" + year);
        }
    }
}

Answer 4

其他答案都是正确的。但既然你反复询问是否有更简单的方法，是的，就有了。

日期时间库

使用合适的日期时间库而不是滚动自己的日期时间逻辑。日期时间工作令人惊讶地棘手且令人困惑。

但要避免与Java捆绑在一起的臭名昭着的java.util.Date/.Calendar类。在Java 8中，这些类已被新的java.time package取代。该软件包的灵感来自古老的Joda-Time库。

约达时间

当您只想要一个没有任何时间的日期时，Joda-Time会提供LocalDate课程。

以下是一些使用Joda-Time 2.3的示例代码。

int year = 2001;
int month = 2;
int day = 3;
LocalDate birthDate = new LocalDate( year, month, day );

DateTimeFormatter formatter = DateTimeFormat.forPattern( "'Your Birthdate : 'EEEE - d/M/yyyy" );
String output = formatter.print( birthDate );

System.out.println( output );

跑步时......

Your Birthdate : Saturday - 3/2/2001

本地化

更好的是，日期时间库可以完成本地化措辞和订单的工作。

int year = 2001;
int month = 2;
int day = 3;
LocalDate birthDate = new LocalDate( year, month, day );

java.util.Locale localeQuébécois = java.util.Locale.CANADA_FRENCH;
DateTimeFormatter formatter = DateTimeFormat.forStyle( "F-" ).withLocale( localeQuébécois );
String output = formatter.print( birthDate );

System.out.println( output );

跑步时......

samedi 3 février 2001

与dayofweek错误的一天

4 个答案:

日期时间库

约达时间

本地化