Comparable和Comparator排序

一般情况下我们都是对数字或者字符串排序,如何对对象进行排序呢?例如Order对象Student对象,那么就需要Order对象、Student对象实现Comparable接口

按照年龄从大到小排序


@Getter
@Setter
@ToString
public class Student implements Comparable<Student> {

    private  int age;
    private String name;
    private int hight;
    @Override
    public int compareTo(Student o) {
        return this.age-o.getAge();
    }
}
    public static void main(String[] args) {
        Student student = new Student();
        student.setAge(10);
        student.setHight(186);
        student.setName("zhangsan");
        Student student1 = new Student();
        student1.setAge(18);
        student1.setHight(165);
        student1.setName("lisi");

        List<Student> list = new ArrayList<>();
        list.add(student);
        list.add(student1);
        //默认按照年龄从小到大排序,因为学生类实现了Comparable的compareTo方法                      
        Collections.sort(list);
        System.out.println("默认按照年龄从小到大排序:"+list);
        //按照默认排序找到年龄最大的                                                    
        System.out.println("按照默认排序找到年龄最大的:"+getMax(student1, student));
        //身高按照从小到大排序                                                       
        Collections.sort(list, new Comparator<Student>() {
            @Override
            public int compare(Student o1, Student o2) {
                return o1.getHight()-o2.getHight();
            }
        });
        System.out.println("身高按照从小到大排序 :"+list);
    }

    public static Comparable getMax(Comparable o1, Comparable o2) {
        int i = o1.compareTo(o2);
        if (i > 1) {
            return o1;
        } else {
            return o2;
        }
    }

网上有说 Comparable 和Comparator用到了策略模式,设计模式不精明的我还没体会粗来 ,在我看来只是用到了多态

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