集合排序问题

package 集合;

import 重写equals和hashcode.Student;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

public class TestList {

    static List<User> list = new ArrayList<User>();
    static User user = new User(1, "李瑜", 24);
    static User user1 = new User(2, "吴建", 26);
    static User user2 = new User(3, "吴建", 25);


    public static void main(String[] args) {


        testDistinct2();
        //list.forEach(System.out::println);

    }


    /**
     * 集合遍历
     * https://destiny1020.blog.youkuaiyun.com/article/details/40340291
     */
    public void traverse() {
        list.add(user);
        list.add(user1);
        list.forEach(user -> System.out.println(user.toString()));
        //list.forEach(System.out::println);
    }


    /**
     * 排序
     * https://blog.youkuaiyun.com/qq_30869501/article/details/85242607
     */
    public void sort() {

        list.add(user);
        list.add(user1);
        list.add(user2);
        System.out.println("排序前");
        list.forEach(User -> System.out.println(User.toString()));

        list.sort(new Comparator<User>() {
            @Override
            public int compare(User o1, User o2) {
                return o2.getAge() - o1.getAge();
            }
        });
        System.out.println("排序后");
        list.forEach(User -> System.out.println(User.toString()));
    }


    /**
     * 集合去重（引用对象）
     */
    private static void testDistinct2() {
        //引用对象的去重，引用对象要实现hashCode和equal方法，否则去重无效
        Student s1 = new Student(1L, "肖战", 15, "浙江");
        Student s2 = new Student(2L, "王一博", 15, "湖北");
        Student s3 = new Student(3L, "杨紫", 17, "北京");
        Student s4 = new Student(4L, "李现", 17, "浙江");
        Student s5 = new Student(1L, "肖战", 15, "浙江");
        List<Student> students = new ArrayList<>();
        students.add(s1);
        students.add(s2);
        students.add(s3);
        students.add(s4);
        students.add(s5);
       // students.stream().distinct().forEach(System.out::println);
        List<Student> studentList= students.stream().distinct().collect(Collectors.toList());
        studentList.forEach(student -> System.out.println(student.getName()));

    }

}