Comparator介面

java中有內建的排序，Arrays.sort()，現在我有一個Student類，類中三個成員變數name,id,age，我現在想以age作為參考進行升序排序，應該如何做，很簡單，只需要自己定義一個類實現Comparator介面即可

import java.util.*;
class Student {
	String name;
	int id,age;
	Student(String name,int id,int age) {
		this.name = name;
		this.id = id;
		this.age = age;
	}
}
public class
 
 ComparetorTest {
	public static class MyCompara implements Comparator<Student> {
		public int compare(Student s1, Student s2) {
			return s1.age - s2.age;
		}
	}
	public static void main(String[] args) {
		Student s1 = new Student("A",1,22);
		Student s2 = new Student("B",3,23);
		Student s3 =
 
 new Student("C",2,21);
		Student[] student = new Student[] {s1,s2,s3};
		Arrays.sort(student, new MyCompara());
		for(int i = 0;i < student.length;i++) 
			System.out.println(student[i].name + " " + student[i].id + " " + student[i].age);
	}
}