我有一个Java对象列表,我想根据多个字段排序。
I have a List of Java objects that I want to sort according to more than one field.
public class graduationCeremony { String campus; String faculty; String building; }是否可以使用 Comparator 或 Comparable 接口根据多个字段对列表排序?我看到的所有例子只根据一个字段排序。换句话说,人们可以通过校园或教师或建筑来排序。我想按照校园,然后是教师,然后是建筑来排序(如在SQL中存在: ORDER BY campus,faculty,building )
Is it possible to use a Comparator or the Comparable interface to sort the list according to multiple fields? All the examples I have seen sort according to only one field. In other words, one can sort by 'campus' OR 'faculty' OR 'building'. I want to sort by 'campus', then 'faculty', then 'building' (as it exists in SQL: ORDER BY campus, faculty, building)
我认为这个问题已经问前,但我不明白接受的答案。
I think this question has been asked before, but I don't understand the accepted answer. Can someone expand or illustrate this answer?
推荐答案您的比较器将如下所示:
Your Comparator would look like this:
public class GraduationCeremonyComparator implements Comparator<graduationCeremony> { public int compare(graduationCeremony o1, graduationCeremony o2) { int value1 = o1.campuspareTo(o2.campus); if (value1 == 0) { int value2 = o1.facultypareTo(o2.faculty); if (value2 == 0) { return o1.buildingpareTo(o2.building); } else { return value2; } return value1; } }基本上它会继续比较你的类的每个连续属性到目前为止,比较的属性是相等的( == 0 )。
Basically it continues comparing each successive attribute of your class whenever the compared attributes so far are equal (== 0).
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