java中实现两个日期相减

在 Java 中可以使用 Java 8 引入的 java.time 包来实现两个日期的相减操作。下面是一个示例代码：

import java.time.Duration;
import java.time.LocalDate;
import java.time.Period;

public class DateSubtraction {
    public static void main(String[] args) {
        // 创建两个日期
        LocalDate date1 = LocalDate.of(2021, 10, 1);
        LocalDate date2 = LocalDate.of(2021, 10, 10);
        
        // 计算日期之间的天数差
        long days = Duration.between(date1.atStartOfDay(), date2.atStartOfDay()).toDays();
        System.out.println("Days between " + date1 + " and " + date2 + ": " + days);
        
        // 计算日期之间的月份差和天数差
        Period period = Period.between(date1, date2);
        System.out.println("Period between " + date1 + " and " + date2 + ": " + period.getMonths() + " months and " + period.getDays() + " days");
    }
}

运行以上代码，输出如下：

Days between 2021-10-01 and 2021-10-10: 9
Period between 2021-10-01 and 2021-10-10: 0 months and 9 days