两个LocalDateTimes的Java比较器

Question

名为的自定义类MyCustomClass具有其属性joda LocalDateTime。我需要创建一个java.util.Comparator类，MyCustomClass以按其TimeStamp属性比较实例，该属性的类型为LocalDateTime。我已经阅读了有关此内容的几篇文章（包括这一篇文章），并且尝试了所有方法，但是答案中显示的所有方法似乎都不起作用。例如，以下几种方法会引发编译错误：

import java.time.temporal.ChronoUnit;
import java.util.Comparator;

import org.joda.time.DateTime;
import org.joda.time.Duration;
import org.joda.time.Period;

import my.app.model.MyCustomClass;

public class MyCustomClassComparator implements Comparator<MyCustomClass>{
    public int compare(MyCustomClass mcc1, MyCustomClass mcc2) {
        //this first attempt throws a return type error for the method.
        return Period.fieldDifference(mcc2.getTimestamp(), mcc1.getTimestamp());
        //This next attempt says that LocalDateTimes are not valid arguments
        Duration.between(mcc2.getTimestamp(), mcc1.getTimestamp());
        //The next approach also says LocalDateTimes are not valid arguments.
        DateTime.parse(mcc2.getTimestamp()), mcc1.getTimestamp()).getSeconds();
        //This boilerplate approach says the minus sign is not valid for LocalDateTime
        return mcc1.getTimestamp() - mcc2.getTimestamp();
    }
}

我打算在类似代码的其他地方使用它：

List<MyCustomClass> mccs = new ArrayList<MyCustomClass>();
// Sort by time stamp:
Collections.sort(mccs, new MyCustomClassComparator());

如何编写一个Comparator类，以MyCustomClass根据其Joda LocalDateTime属性比较实例？

Answer 1

如果您只需要一个比较器实例：

类似于I?ya Bursov的回答，因为 LocalDateTime 实现了可比性，您可以使用Comparator.comparing

Comparator.comparing(MyCustomClass::getTimestamp)

Answer 2

LocalDateTime实现类似的接口，因此您可以实现比较器，例如：

public class MyCustomClassComparator implements Comparator<MyCustomClass> {
    @Override
    public int compare(final MyCustomClass mcc1, final MyCustomClass mcc2) {
        return mcc1.getTimestamp().compareTo(mcc2.getTimestamp());
    }
}