iCal4j 示例片段产生错误的输出

Question

当我运行此 link 下的代码片段时，不会产生任何输出。

https://www.ical4j.org/examples/model/#creating-a-meeting-of-four-hour-duration

该代码仅打印出以下内容：

BEGIN:VCALENDAR
END:VCALENDAR

如果我做错了什么，请有人提出建议。

P.S.: 我已经纠正了编译错误，现在代码运行没问题了。

这是我运行ning 更正后的代码片段：

import net.fortuna.ical4j.data.CalendarOutputter
import net.fortuna.ical4j.model.DateTime
import net.fortuna.ical4j.model.TimeZoneRegistry
import net.fortuna.ical4j.model.TimeZoneRegistryFactory
import net.fortuna.ical4j.model.component.VEvent
import net.fortuna.ical4j.model.component.VTimeZone
import net.fortuna.ical4j.model.parameter.Cn
import net.fortuna.ical4j.model.parameter.Role
import net.fortuna.ical4j.model.property.Attendee
import net.fortuna.ical4j.model.property.CalScale
import net.fortuna.ical4j.model.property.ProdId
import net.fortuna.ical4j.model.property.Uid
import net.fortuna.ical4j.util.Calendars
import net.fortuna.ical4j.util.MapTimeZoneCache
import net.fortuna.ical4j.util.RandomUidGenerator
import net.fortuna.ical4j.util.UidGenerator

import java.time.LocalDateTime
import java.time.Month
import java.time.ZoneId

System.setProperty("net.fortuna.ical4j.timezone.cache.impl", MapTimeZoneCache.class.getName());
// Create a TimeZone
TimeZoneRegistry registry = TimeZoneRegistryFactory.getInstance().createRegistry();
TimeZone timezone = registry.getTimeZone("America/Mexico_City");
VTimeZone tz = timezone.getVTimeZone();

// Start Date is on: April 1, 2008, 9:00 am
java.util.Calendar startDate = new GregorianCalendar();
startDate.setTimeZone(timezone);
startDate.set(java.util.Calendar.MONTH, java.util.Calendar.APRIL);
startDate.set(java.util.Calendar.DAY_OF_MONTH, 1);
startDate.set(java.util.Calendar.YEAR, 2008);
startDate.set(java.util.Calendar.HOUR_OF_DAY, 9);
startDate.set(java.util.Calendar.MINUTE, 0);
startDate.set(java.util.Calendar.SECOND, 0);

// End Date is on: April 1, 2008, 13:00
java.util.Calendar endDate = new GregorianCalendar();
endDate.setTimeZone(timezone);
endDate.set(java.util.Calendar.MONTH, java.util.Calendar.APRIL);
endDate.set(java.util.Calendar.DAY_OF_MONTH, 1);
endDate.set(java.util.Calendar.YEAR, 2008);
endDate.set(java.util.Calendar.HOUR_OF_DAY, 13);
endDate.set(java.util.Calendar.MINUTE, 0);
endDate.set(java.util.Calendar.SECOND, 0);

// Create the event
String eventName = "Progress Meeting";
LocalDateTime start = LocalDateTime.of(2022, Month.APRIL, 30, 12, 00)
LocalDateTime end = LocalDateTime.of(2022, Month.APRIL, 30, 12, 30)
VEvent meeting = new VEvent(start, end, eventName);

// add timezone info..
meeting.getProperties().add(tz.getTimeZoneId().get());

// generate unique identifier..
UidGenerator ug = new RandomUidGenerator();
Uid uid = ug.generateUid();
meeting.getProperties().add(uid);

// add attendees..
Attendee dev1 = new Attendee(URI.create("mailto:dev1@mycompany.com"));
dev1.getParameters().add(Role.REQ_PARTICIPANT);
dev1.getParameters().add(new Cn("Developer 1"));
meeting.getProperties().add(dev1);

Attendee dev2 = new Attendee(URI.create("mailto:dev2@mycompany.com"));
dev2.getParameters().add(Role.OPT_PARTICIPANT);
dev2.getParameters().add(new Cn("Developer 2"));
meeting.getProperties().add(dev2);

// Create a calendar
net.fortuna.ical4j.model.Calendar icsCalendar = new net.fortuna.ical4j.model.Calendar();
icsCalendar.getProperties().add(new ProdId("-//Events Calendar//iCal4j 1.0//EN"));
icsCalendar.getProperties().add(CalScale.GREGORIAN);



// Add the event and print
icsCalendar.getComponents().add(meeting);
System.out.println(icsCalendar);

OutputStream byteOutputStream = new ByteArrayOutputStream();
CalendarOutputter calendarOutputter = new CalendarOutputter(false)
calendarOutputter.output(icsCalendar, byteOutputStream)

println new String(byteOutputStream.toByteArray())

Answer 1

我想通了。我使用的是 4.0.0-alpha 版本。但是，当我将它切换到版本：3.2.2 时，它工作正常。

iCal4j 示例片段产生错误的输出

iCal4j example snippet produces the wrong output

ical4j