java中如何实现对类的对象进行排序

public class Student {
 private String name;
 private int age;
 public Student() {}

 public Student(String name, int age) {
 this.name = name;
 this.age = age;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public int getAge() {
 return age;
 }

 public void setAge(int age) {
 this.age = age;
 }
}

public class Student implements Comparable<Student>{

 private String name;
 private int age;
 public Student() {}

 public Student(String name, int age) {
 this.name = name;
 this.age = age;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public int getAge() {
 return age;
 }

 public void setAge(int age) {
 this.age = age;
 }

 /**
 * 将对象按姓名字典序升序排序
 * @param o
 * @return
 */

 @Override

 public int compareTo(Student o) {
 return this.name.compareTo(o.getName());
 }

 @Override
 public String toString() {
 return "Student{" +
  "name='" + name + '\'' +
  ", age=" + age +
  '}';
 }

}

public class Client {

 public static void main(String[] args){
 List<Student> students = new ArrayList<>();
 students.add(new Student("a", 18));
 students.add(new Student("c", 19));
 students.add(new Student("b", 20));

 Collections.sort(students, new Comparator<Student>() {
  @Override
  public int compare(Student o1, Student o2) {
  return o1.getAge()>o2.getAge()? -1:(o1.getAge()==o2.getAge()? 0:1);
  }
 });

 for(Student student:students){
  System.out.println(student.toString());
 }
 }
}