list集合的排序

list集合的排序

使用常用的sort方法排序和stream流的方式排序

package com.liucy.meiriyilian.sort;

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

/**
 * @Author liucy
 * @Date 2024/4/16 13:48
 * @Desc list集合排序的方式
 */
public class ListSortDemo {

    public static void main(String[] args) {
//        List<User> userList = List.of(
//                new User("111", "徐汇区", 20, 13564181485L),
//                new User("222", "浦东新区", 25, 13654782145L),
//                new User("333", "黄浦区", 30, 13765478921L)
//        );

        List<User> userList = new ArrayList<User>();
        userList.add(new User("111", "徐汇区", 40, 13564181485L));
        userList.add(new User("222", "浦东新区", 20, 13654782145L));
        userList.add(new User("333", "黄浦区", 25, 13765478921L));
        System.out.println("排序前");
        userList.forEach(System.out::println);
//        sortByCompare(userList);
        sortByStream(userList);

    }

    /**
     * 按照compare排序
     * @param userList
     */
    private static void sortByCompare(List<User> userList) {
        Collections.sort(userList, new Comparator<User>() {

            @Override
            public int compare(User o1, User o2) {
                if (o1.getAge() > o2.getAge()) {
                    return 1;
                } else if (o1.getAge() < o2.getAge()) {
                    return -1;
                } else {
                    return 0;
                }
            }
        });
        System.out.println("排序后");
        userList.forEach( user -> System.out.println(user.toString()));
    }

    private static void sortByStream(List<User> userList) {
        userList = userList.stream().sorted(Comparator.comparingInt(User::getAge)).collect(Collectors.toList());
        System.out.println("排序后");
        userList.forEach(System.out::println);
    }
}