Comparator

public class Demo_Set {
    public static void main(String[] args) {
        Person p1 = new Person("李",18);
        Person p2 = new Person("王",10);
        List<Person> data1 = new ArrayList<Person>();
        data1.add(p1);
        data1.add(p2);
        //用Comparator的实现类排序
        Collections.sort(data1,new AscAgeComparator());
        for (Person a : data1) {
            System.out.println(a);
        }
    }
    //定义一个AscAgeComparator
    private static class AscAgeComparator implements Comparator<Person> {

        @Override
        public int compare(Person p1, Person p2) {
            return p1.getAge() - p2.getAge();
        }
    }
    static class Person  {
        private String name;
        private int age;

        /*@Override
        public int compareTo(Person o) {
            //this 与 o比较
            //返回的数据： 负数this小/0一样大/正数this大
            if(this.age>o.age){
                return 1;
            }else if(this.age<o.age){
                return -1;

            }
            return 0;
        }*/
        @Override
        public String toString() {
            return "Person{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }

        public Person() {
        }

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

        public int getAge() {
            return age;
        }

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

        public String getName() {
            return name;
        }

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