介绍
在本实验中,我们将学习如何使用 Java LocalDate
类中的 withDayOfYear()
方法,通过指定新的年日值来创建一个日期。
在本实验中,我们将学习如何使用 Java LocalDate
类中的 withDayOfYear()
方法,通过指定新的年日值来创建一个日期。
在 ~/project
目录下创建一个文件 LocalDateWithDayOfYear.java
,并写入以下代码:
import java.time.LocalDate;
public class LocalDateWithDayOfYear {
public static void main(String[] args) {
System.out.println("Original date: ");
LocalDate localDate = LocalDate.of(2002, 01, 10);
System.out.println(localDate);
}
}
使用以下命令编译并运行代码:
javac LocalDateWithDayOfYear.java && java LocalDateWithDayOfYear
输出应显示原始日期:
Original date:
2002-01-10
要通过设置新的年日值来创建一个新日期,我们可以使用 withDayOfYear()
方法为日期设置新的年日值。
在 System.out.println(localDate);
行后添加以下代码:
// set day-of-year as 30
localDate = localDate.withDayOfYear(30);
System.out.println("New date with day-of-year set as 30: ");
System.out.println(localDate);
// set day-of-year as 300
localDate = localDate.withDayOfYear(300);
System.out.println("New date with day-of-year set as 300: ");
System.out.println(localDate);
使用以下命令编译并运行代码:
javac LocalDateWithDayOfYear.java && java LocalDateWithDayOfYear
输出应显示设置了新年日值的新日期:
Original date:
2002-01-10
New date with day-of-year set as 30:
2002-01-30
New date with day-of-year set as 300:
2002-10-27
如果生成的日期无效,将会抛出异常。我们可以使用 try-catch 块来处理异常,如下所示:
try {
// set day-of-year as 366 (invalid for non-leap year)
localDate = localDate.withDayOfYear(366);
System.out.println(localDate);
} catch (Exception e) {
System.out.println("Invalid date: " + e.getMessage());
}
使用以下命令编译并运行代码:
javac LocalDateWithDayOfYear.java && java LocalDateWithDayOfYear
输出应显示无效日期异常的消息:
Original date:
2002-01-10
New date with day-of-year set as 30:
2002-01-30
New date with day-of-year set as 300:
2002-10-27
Invalid date: Invalid date 'DayOfYear 366' as '2002' is not a leap year
在本实验中,我们学习了如何使用 Java LocalDate
类中的 withDayOfYear()
方法,通过设置新的年日值来创建日期。我们还学习了在设置新的年日值时如何处理无效日期异常。