如何在Java 8中添加或减去日期？
新的Java8java.time.LocalDate类提供了plus()和minus()方法，可以向LocalDate对象添加或从对象中减去一定量的周期。
期间使用java.time.Period类表示。要创建一个实例Period，我们可以使用of()，ofDays()，ofWeeks()，ofMonths()和ofYears()方法。
让我们来看一个使用class的plus()andminus()方法LocalDate在以下代码片段中进行加减的示例：
package org.nhooo.example.datetime;
import java.time.LocalDate;
import java.time.Period;
public class DateAddSubtract {
public static void main(String[] args) {
//以天，周，月和年为单位创建时间段。
Period p1 = Period.ofDays(7);
Period p2 = Period.ofWeeks(2);
Period p3 = Period.ofMonths(1);
Period p4 = Period.ofYears(1);
Period p5 = Period.of(1, 1, 7);
//获取当前日期，并使用以下命令在当前日期中添加一些句点
//plus()方法。
LocalDate now = LocalDate.now();
LocalDate date1 = now.plus(p1);
LocalDate date2 = now.plus(p2);
LocalDate date3 = now.plus(p3);
LocalDate date4 = now.plus(p4);
LocalDate date5 = now.plus(p5);
//打印出将一些期间添加到当前日期的结果。
System.out.printf("Add some period to the date: %s%n", now);
System.out.printf("Plus %7s = %s%n", p1, date1);
System.out.printf("Plus %7s = %s%n", p2, date2);
System.out.printf("Plus %7s = %s%n", p3, date3);
System.out.printf("Plus %7s = %s%n", p4, date4);
System.out.printf("Plus %7s = %s%n%n", p5, date5);
//使用minus()方法从日期中减去某个时间段。
System.out.printf("Subtract some period from the date: %s%n", now);
System.out.printf("Minus %7s = %s%n", p1, now.minus(p1));
System.out.printf("Minus %7s = %s%n", p2, now.minus(p2));
System.out.printf("Minus %7s = %s%n", p3, now.minus(p3));
System.out.printf("Minus %7s = %s%n", p4, now.minus(p4));
System.out.printf("Minus %7s = %s%n%n", p5, now.minus(p5));
}
}这是上面代码片段的结果：
Add some period to the date: 2016-01-29 Plus P7D = 2016-02-05 Plus P14D = 2016-02-12 Plus P1M = 2016-02-29 Plus P1Y = 2017-01-29 Plus P1Y1M7D = 2017-03-07 Subtract some period from the date: 2016-01-29 Minus P7D = 2016-01-22 Minus P14D = 2016-01-15 Minus P1M = 2015-12-29 Minus P1Y = 2015-01-29 Minus P1Y1M7D = 2014-12-22