1、在Java 7中,java.time包不存在,所以我们需要使用java.util.Calendar和java.util.Date类来实现类似的功能。
以下是一个基于Java 7的示例代码:
import java.util.Calendar;
import java.util.Date;
public class DateCalculator {
public static Date calculateDate(Date startDate, Date endDate, int dayOfWeek) {
Calendar startCal = Calendar.getInstance();
startCal.setTime(startDate);
Calendar endCal = Calendar.getInstance();
endCal.setTime(endDate);
// 确保输入的dayOfWeek在正确的范围内(1-7,其中1代表周一,7代表周日)
if (dayOfWeek < 1 || dayOfWeek > 7) {
throw new IllegalArgumentException("Invalid dayOfWeek value. Must be between 1 and 7.");
}
// 将输入的dayOfWeek转换为Calendar的周几(Calendar.MONDAY, Calendar.SUNDAY等)
int targetDay = dayOfWeek + 1; // 因为Calendar的周日是1,周一到周六依次递增
// 查找开始日期之后的第一个目标周几的日期
while (startCal.getTime().before(endDate)) {
if (startCal.get(Calendar.DAY_OF_WEEK) == targetDay) {
break;
}
startCal.add(Calendar.DAY_OF_MONTH, 1);
}
return startCal.getTime();
}
public static void main(String[] args) throws Exception {
long startDateTimestamp = 1377753600000L; // 开始日期的Unix时间戳,例如2013-09-01 00:00:00
long endDateTimestamp = 1380345600000L; // 结束日期的Unix时间戳,例如2013-10-01 00:00:00
int targetDayOfWeek = 3; // 周三(在Java中,1=Monday, 7=Sunday)
Date startDate = new Date(startDateTimestamp);
Date endDate = new Date(endDateTimestamp);
Date calculatedDate = calculateDate(startDate, endDate, targetDayOfWeek);
if (calculatedDate != null) {
System.out.println("The next occurrence of " + targetDayOfWeek + " (Wednesday) between "
+ startDate + " and " + endDate + " is on: " + calculatedDate);
} else {
System.out.println("There is no occurrence of the specified weekday between the given dates.");
}
}
}
这段代码首先将开始日期和结束日期转换为Calendar对象,然后使用循环寻找开始日期之后的第一个指定周几的日期。如果找到,就返回这个日期;否则,返回null。在main方法中,我们使用Unix时间戳创建了开始和结束日期,并调用了calculateDate函数。
2、在Java 8中,根据开始时间、结束时间和周几来计算日期,可以使用java.time包下的类,如LocalDate、DayOfWeek等。
以下是一个示例代码,展示了如何实现这一功能:
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.temporal.TemporalAdjusters;
public class DateCalculator {
public static LocalDate calculateDate(LocalDate startDate, LocalDate endDate, int dayOfWeek) {
// 确保输入的dayOfWeek在正确的范围内(1-7,其中1代表周一,7代表周日)
if (dayOfWeek < 1 || dayOfWeek > 7) {
throw new IllegalArgumentException("Invalid dayOfWeek value. Must be between 1 and 7.");
}
// 将输入的dayOfWeek转换为DayOfWeek枚举值
DayOfWeek targetDay = DayOfWeek.of(dayOfWeek);
// 查找开始日期之后的第一个目标周几的日期
LocalDate firstOccurrence = startDate.with(TemporalAdjusters.nextOrSame(targetDay));
// 如果第一个出现的日期在结束日期之后,则返回null,表示在指定区间内没有找到符合条件的日期
if (firstOccurrence.isAfter(endDate)) {
return null;
}
return firstOccurrence;
}
public static void main(String[] args) {
LocalDate startDate = LocalDate.of(2023, 9, 1); // 开始日期
LocalDate endDate = LocalDate.of(2023, 9, 30); // 结束日期
int targetDayOfWeek = 3; // 周三(在Java中,1=Monday, 7=Sunday)
LocalDate calculatedDate = calculateDate(startDate, endDate, targetDayOfWeek);
if (calculatedDate != null) {
System.out.println("The next occurrence of " + targetDayOfWeek + " (Wednesday) between "
+ startDate + " and " + endDate + " is on: " + calculatedDate);
} else {
System.out.println("There is no occurrence of the specified weekday between the given dates.");
}
}
}
这段代码首先定义了一个calculateDate方法,它接收开始日期、结束日期以及表示周几的整数作为参数。然后,使用TemporalAdjusters.nextOrSame方法找到开始日期之后的第一个指定周几的日期。如果这个日期在结束日期之后,则返回null。最后,在main方法中调用此函数,并打印结果。
请注意,Java的DayOfWeek枚举中,1代表星期一,2代表星期二,依此类推,直到7代表星期日。因此,如果要查找周日的日期,应传入7。