java.lang.Comparable接口：比较对象大小的标准接口，自然排序的接口 这种排序被称为类的自然排序，类的compareTo方法被称为它的自然比较方法。
需要实现下面这个抽象的方法 int compareTo(Object obj)
这样子的实现（具体的看代码）
当前对象this比obj对象大，返回正整数 当前对象this比obj对象大，返回负整数 当前对象this和obj相等时，返回0；更加详细的解释看这个： https://blog.csdn.net/qq_41005604/article/details/106864077
java.util.Comparator接口：比较对象大小的标准接口2.定制排序接口 也有一个抽象方法： int compare(Object o1,Object o2)
这样子的实现（具体的看代码）
o1对象比o2对象大，返回正整数 o1对象比o2对象小，返回负整数 o1对象和o2对象相等，返回0说明：这个接口不是在学生类那里进行实现的，而是重新创建的，详情看代码
默认是按照学号来排序的，但是突然需求增加了，又要增加按照成绩进行排序，这个时候用Comparable接口已经满足不了功能需求了，这个时候就需要使用Comparator来实现这个功能。
public class TestComparable { public static void main(String[] args) { Student[] arr = new Student[3]; arr[0] = new Student(2,"王小二",89); arr[1] = new Student(3,"张三",87); arr[2] = new Student(1,"李四",59); //现在我用Arrays.sort()进行排序,先按照自然顺序进行排序 Arrays.sort(arr); System.out.println("按照学号进行排序："); for (int i = 0; i < arr.length; i++) { System.out.println(arr[i]); } System.out.println("----------"); //按照成绩在重新进行排序 class StudentScoreCompare implements Comparator{ @Override public int compare(Object o1, Object o2) { Student s1 = (Student)o1; Student s2 = (Student)o2; return s1.getScore() - s2.getScore(); } } //在Arrays的类中 //public static void sort(Object[] a , Comparator c) StudentScoreCompare sc = new StudentScoreCompare();//是Comparator接口的实现类对象 Arrays.sort(arr,sc); System.out.println("按照成绩定制规则进行排序进行排序："); for (int i = 0; i < arr.length; i++) { System.out.println(arr[i]); } } } class Student implements Comparable{ private int id; private String name; private int score; public Student() { super(); } public Student(int id, String name, int score) { super(); this.id = id; this.name = name; this.score = score; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getScore() { return score; } public void setScore(int score) { this.score = score; } @Override public String toString() { return "Student [id=" + id + ", name=" + name + ", score=" + score + "]"; } //默认是按照学号进行排序 @Override public int compareTo(Object o) { Student stu = (Student)o; return this.id - stu.id; } }每次使用Comparator都需要创建Comparator的实现类对象有点麻烦，这里就直接给你写成匿名内部类的形式。
import java.util.Arrays; import java.util.Comparator; public class TestComparator { @SuppressWarnings("all")//抑制所有警告 public static void main(String[] args) { Student[] arr = new Student[3]; arr[0] = new Student(2,"王小二",89); arr[1] = new Student(3,"张三",87); arr[2] = new Student(1,"李四",59); //在Arrays的类中 //public static void sort(Object[] a , Comparator c) Arrays.sort(arr,new Comparator() { @Override public int compare(Object o1, Object o2) { Student s1 = (Student) o1; Student s2 = (Student) o2; return s1.getScore() - s2.getScore(); } }); for (int i = 0; i < arr.length; i++) { System.out.println(arr[i]); } } } class Student{ private int id; private String name; private int score; public Student() { super(); } public Student(int id, String name, int score) { super(); this.id = id; this.name = name; this.score = score; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getScore() { return score; } public void setScore(int score) { this.score = score; } @Override public String toString() { return "Student [id=" + id + ", name=" + name + ", score=" + score + "]"; } }