我有两个LocalDates代表一些时间间隔。现在我必须得到所有星期五的LocalDates，这个间隔包含。 最简单的方法吗？
答案 0 :(得分：6)
package org.life.java.so.questions;
import org.joda.time.DateTime;
import org.joda.time.DateTimeConstants;
/**
*
* @author Jigar
*/
public class JodaTimeDateTraverseQuestion {
public static void main(String[] args) {
DateTime startDt = new DateTime(2010,12,1,0,0,0,0);//1st Dec 2010
DateTime endDt = new DateTime(2010,12,31,0,0,0,0);//31st Dec 2010
DateTime tempDate = new DateTime(startDt.getMillis());
while(tempDate.compareTo(endDt) <=0 ){
if(tempDate.getDayOfWeek() != DateTimeConstants.SATURDAY && tempDate.getDayOfWeek() != DateTimeConstants.SUNDAY){
System.out.println(""+tempDate);
}
tempDate = tempDate.plusDays(1);
}
}
}
答案 1 :(得分：4)
解决方案：懒洋洋地一步一周。
import org.joda.time.LocalDate;
import java.util.Iterator;
public class DayOfWeekIterator implements Iterator<LocalDate>{
private final LocalDate end;
private LocalDate nextDate;
public DayOfWeekIterator(LocalDate start, LocalDate end, int dayOfWeekToIterate){
this.end = end;
nextDate = start.withDayOfWeek(dayOfWeekToIterate);
if (start.getDayOfWeek() > dayOfWeekToIterate) {
nextDate = nextDate.plusWeeks(1);
}
}
public boolean hasNext() {
return !nextDate.isAfter(end);
}
public LocalDate next() {
LocalDate result = nextDate;
nextDate = nextDate.plusWeeks(1);
return result;
}
public void remove() {
throw new UnsupportedOperationException();
}
}
测试
import org.joda.time.DateTimeConstants;
import org.joda.time.LocalDate;
public class DayOfWeekIteratorTest {
public static void main(String[] args) {
LocalDate startDate = new LocalDate(2010, 12, 1);//1st Dec 2010
LocalDate endDate = new LocalDate(2010, 12, 31);//31st Dec 2010
DayOfWeekIterator it = new DayOfWeekIterator(startDate, endDate, DateTimeConstants.FRIDAY);
while (it.hasNext()) {
System.out.println(it.next());
}
}
}
答案 2 :(得分：0)
java.time.LocalDate.of( 2018 , Month.JANUARY , 23 ) // A date-only class in the modern *java.time* classes that supplant both Joda-Time and the troublesome old date-time classes.
.with(
TemporalAdjusters.next( DayOfWeek.FRIDAY ) // Nifty `TemporalAdjuster` implementation for moving to another date. Immutable Objects pattern means a new object is returned based on the original which remains unmodified.
)
.isBefore( // Compare `LocalDate` objects with `isBefore`, `isAfter`, and `isEqual`.
LocalDate.of( 2018 , Month.FEBRUARY , 27 );
)
仅供参考，Joda-Time项目现在位于maintenance mode，团队建议迁移到java.time课程。
定义你的停止＆amp;启动LocalDate个对象。
LocalDate start = LocalDate.of( 2018 , Month.JANUARY , 23 );
LocalDate stop = LocalDate.of( 2018 , Month.FEBRUARY , 27 );
// TODO: Verify start.isBefore( stop ).
收集我们发现的星期五日期。您可以通过调整集合大小来优化一点。
// Pre-size the collection.
int initialCapacity = ( int ) ( ChronoUnit.WEEKS.between( start , stop ) + 2 ); // Adding two for good measure.
List < LocalDate > fridays = new ArrayList <>( initialCapacity );
确定第一个星期五，使用开始日期，如果它本身是星期五。使用TemporalAdjuster课程中提供的一对TemporalAdjusters实施：next(DayOfWeek)＆amp; nextOrSame(DayOfWeek)。通过DayOfWeek enum传递所需的星期几，七个预定义的对象，一个星期一到星期日的每一天。
LocalDate friday = start.with( TemporalAdjusters.nextOrSame( DayOfWeek.FRIDAY ) );
while ( friday.isBefore( stop ) )
{
fridays.add( friday ); // Remember this Friday date.
// Setup next loop.
friday = friday.with( TemporalAdjusters.next( DayOfWeek.FRIDAY ) );
}
System.out.println( "From " + start + " to " + stop + " = " + fridays );
2018-01-23至2018-02-27 = [2018-01-26,2018-02-02,2018-02-09,2018-02-16,2018-02-23]
java.time框架内置于Java 8及更高版本中。这些类取代了麻烦的旧legacy日期时间类，例如java.util.Date，Calendar和＆amp; SimpleDateFormat
现在位于Joda-Time的maintenance mode项目建议迁移到java.time类。
要了解详情，请参阅Oracle Tutorial。并搜索Stack Overflow以获取许多示例和解释。规范是JSR 310。
您可以直接与数据库交换 java.time 对象。使用符合JDBC driver或更高版本的JDBC 4.2。不需要字符串，不需要java.sql.*类。
从哪里获取java.time类？
ThreeTen-Extra项目使用其他类扩展java.time。该项目是未来可能添加到java.time的试验场。您可以在此处找到一些有用的课程，例如Interval，YearWeek，YearQuarter和more。