我有一个 java 程序，它将检查每个项目的开始日期和结束日期。每个项目必须有自己特定的开始日期和结束日期范围。如果新的开始日期和结束日期的范围在旧的开始日期和结束日期范围内，系统将提示错误消息。例如：
Company: ABC
Item_Number Start Date End Date
Item 11A 01/08/2014 01/09/2014
Item 11B 02/09/2014 30/09/2014
Item 11C 18/08/2014 30/08/2014
当最终用户尝试添加项目 11C 时，系统会提示错误消息。有什么建议可以解决这个问题吗？非常感谢。
【问题讨论】：
Date#before, Date#after...和某种循环
你可以这样做：
public class DateDemo {
public static void main(String[] args) {
Date date = new Date(11, 5, 21);
Date date2 = new Date(15, 1, 21);
// tests if date2 is before date and prints result
boolean before = date2.before(date);
if (before) {
System.out.println("Date 2 is before date: " + before);
throw new RuntimeException("Error with dates");
}
}
}
当然，这只是一个例子，因为我不知道这个日期是从哪里来的。 而且您必须在循环中执行此操作才能验证所有这些。
【讨论】：
使用Guava Range 可以简化您的问题
public class ValidateDateFall {
public static void main(String args[]) throws ParseException {
List<Item> itemArr = Lists.newArrayList();
itemArr.add(new Item("11A", "01/08/2014", "01/09/2014"));
itemArr.add(new Item("11B", "02/09/2014", "30/09/2014"));
itemArr.add(new Item("11C", "18/08/2014", "30/08/2014"));
Range<Date> currentPeriod = null;
for(Item item:itemArr) {
// Initial Current Range
if(currentPeriod == null) {
currentPeriod = Range.closed(item.startDate, item.endDate);
continue;
}
// Check item start date and end date is within in current period
Range<Date> itemRange = Range.closed(item.startDate, item.endDate);
boolean isEnclosed = currentPeriod.encloses(itemRange);
// if within current item then prompt error message or not then extend the period
if(isEnclosed) {
System.out.println("Prompt Error Message:" + item);
} else {
currentPeriod = currentPeriod.span(itemRange);
}
}
}
}
// Item Pojo
class Item{
private static final SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
public String name;
public Date startDate;
public Date endDate;
public Item(String name, String startDateStr, String endDate) throws ParseException {
this.name = name;
this.startDate = sdf.parse(startDateStr);
this.endDate = sdf.parse(endDate);;
}
@Override
public String toString() {
return Objects.toStringHelper(this.getClass()).add("start date", startDate).add("end date", endDate).toString();
}
}
【讨论】：
这里是使用Joda-Time 和Guava's Range 的可能实现的简单单元测试。
import com.google.common.collect.Lists;
import com.google.common.collect.Range;
import org.joda.time.LocalDate;
import org.junit.Test;
import java.util.List;
import static org.junit.Assert.assertEquals;
public class ItemDateRangeTest {
static class Item {
private final String id;
private final LocalDate startDate;
private final LocalDate endDate;
public Item(String id, LocalDate startDate, LocalDate endDate) {
this.id = id;
this.startDate = startDate;
this.endDate = endDate;
}
public String getId() {
return id;
}
public LocalDate getStartDate() {
return startDate;
}
public LocalDate getEndDate() {
return endDate;
}
public Range<LocalDate> getRange() {
// Closed range includes the lower and upper bounds
return Range.closed(startDate, endDate);
}
}
static class ItemStore {
private final List<Item> items = Lists.newArrayList();
public void add(Item newItem) throws IllegalArgumentException{
for (Item item : items) {
if (item.getRange().isConnected(newItem.getRange())) {
throw new IllegalArgumentException("error: date range overlap!");
}
}
items.add(newItem);
}
public List<Item> getItems() {
return items;
}
}
@Test()
public void testItemDateRangeNoOverlap() {
final ItemStore itemStore = new ItemStore();
Item itemA = new Item("11A", new LocalDate(2014, 8, 1), new LocalDate(2014, 9, 1));
Item itemB = new Item("11B", new LocalDate(2014, 9, 2), new LocalDate(2014, 9, 30));
itemStore.add(itemA);
itemStore.add(itemB);
assertEquals(itemStore.getItems().get(0), itemA);
assertEquals(itemStore.getItems().get(1), itemB);
}
@Test(expected = IllegalArgumentException.class)
public void testItemDateRangeWithOverlap() {
final ItemStore itemStore = new ItemStore();
itemStore.add(new Item("11A", new LocalDate(2014,8,1), new LocalDate(2014,9,1)));
itemStore.add(new Item("11B", new LocalDate(2014,9,2), new LocalDate(2014,9,30)));
itemStore.add(new Item("11C", new LocalDate(2014,8,18), new LocalDate(2014,8,30)));
}
}
【讨论】：
日期范围可能很棘手...
首先，您要确保原始开始日期不等于比较开始日期或结束日期，并且原始结束日期不等于比较开始日期或结束日期
startDate.equals(originalStartDate) ||
startDate.equals(originalEndDate) ||
endDate.equals(originalStartDate) ||
endDate.equals(originalEndDate)
如果一切正常 (false)，那么您需要检查比较开始日期是否介于原始开始日期或结束日期之间，以及比较结束日期是否介于原始开始日期或结束日期之间...
(startDate.after(originalStartDate) || startDate.before(originalEndDate) ||
(endDate.after(originalStartDate) || endDate.before(originalEndDate)
这会尝试捕获两个范围相互包含或重叠的任何点...
因为我实际上写了一些测试代码......
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
public class CompareDates {
public static void main(String[] args) {
try {
List<Event> events = new ArrayList<Event>(3);
events.add(new Event(toDate("01/08/2014"), toDate("01/09/2014")));
events.add(new Event(toDate("02/09/2014"), toDate("30/09/2014")));
Date start = toDate("18/08/2014");
Date end = toDate("30/08/2014");
for (Event evt : events) {
System.out.println(evt.conflicts(start, end));
}
} catch (ParseException exp) {
exp.printStackTrace();
}
}
public static Date toDate(String value) throws ParseException {
return new SimpleDateFormat("dd/MM/yyyy").parse(value);
}
public static class Event {
private Date startDate;
private Date endDate;
public Event(Date startDate, Date endDate) {
this.startDate = startDate;
this.endDate = endDate;
}
public boolean conflicts(Date start, Date end) {
return start.equals(startDate) ||
start.equals(endDate) ||
end.equals(startDate) ||
end.equals(endDate) ||
(start.after(startDate) && start.before(endDate)) ||
(end.after(startDate) && end.before(endDate));
}
}
}
【讨论】：