自定义对象(类) 集合排序

package org.onepiece;

import java.util.Date;

//自定义类
public class User {

    public User() {
    }

    public User(Integer id, String name, Date addTime) {
        this._id = id;
        this._name = name;
        this._addTime = addTime;
    }

    private Integer _id;
    private String _name;
    private Date _addTime;


    public Integer getId() {
        return _id;
    }
    public void setId(Integer id) {
        this._id = id;
    }


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


    public Date get_AddTime() {
        return _addTime;
    }
    public void set_AddTime(Date addTime) {
        this._addTime = addTime;
    }

}

 

package org.onepiece;

import java.lang.String;
import java.util.*;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) {

        List<User> users = new ArrayList<>();
        users.add(new User(1, "AA", new Date()));
        users.add(new User(3, "BB", new Date()));
        users.add(new User(5, "CC", new Date()));
        users.add(new User(2, "DD", new Date()));
        users.add(new User(4, "EE", new Date()));
        users.add(new User(6, "FF", new Date()));
        users.add(new User(7, "GG", new Date()));
        users.add(new User(8, "HH", new Date()));
        users.add(new User(3, "aa", new Date()));
        users.add(new User(5, "bb", new Date()));

        for (User u : users) {
            System.out.println(u.getId() + "--" + u.getName());
        }

        /**
         * 1--AA
         * 3--BB
         * 5--CC
         * 2--DD
         * 4--EE
         * 6--FF
         * 7--GG
         * 8--HH
         * 3--aa
         * 5--bb
         * */
    }
}

 

升序

package org.onepiece;

import java.lang.String;
import java.util.*;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) {

        List<User> users = new ArrayList<>();
        users.add(new User(1, "AA", new Date()));
        users.add(new User(3, "BB", new Date()));
        users.add(new User(5, "CC", new Date()));
        users.add(new User(2, "DD", new Date()));
        users.add(new User(4, "EE", new Date()));
        users.add(new User(6, "FF", new Date()));
        users.add(new User(7, "GG", new Date()));
        users.add(new User(8, "HH", new Date()));
        users.add(new User(3, "aa", new Date()));
        users.add(new User(5, "bb", new Date()));


　　　　 //按Id升序
        List<User> ascList = users.stream()
                .sorted((Comparator.comparingInt(x -> x.getId())))
                .collect(Collectors.toList());

        ascList.forEach(u -> {
            System.out.println(u.getId() + "--" + u.getName());
        });

        /**
         * 1--AA
         * 2--DD
         * 3--BB
         * 3--aa
         * 4--EE
         * 5--CC
         * 5--bb
         * 6--FF
         * 7--GG
         * 8--HH
         * */
    }
}

 

倒序

package org.onepiece;

import java.lang.String;
import java.util.*;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) {

        List<User> users = new ArrayList<>();
        users.add(new User(1, "AA", new Date()));
        users.add(new User(3, "BB", new Date()));
        users.add(new User(5, "CC", new Date()));
        users.add(new User(2, "DD", new Date()));
        users.add(new User(4, "EE", new Date()));
        users.add(new User(6, "FF", new Date()));
        users.add(new User(7, "GG", new Date()));
        users.add(new User(8, "HH", new Date()));
        users.add(new User(3, "aa", new Date()));
        users.add(new User(5, "bb", new Date()));


　　　　 //按Id倒序
        List<User> descList = users.stream()
                .sorted(Comparator.comparingInt(User::getId).reversed())
                .collect(Collectors.toList());

        descList.forEach(u -> {
            System.out.println(u.getId() + "--" + u.getName());
        });

        /**
         * 8--HH
         * 7--GG
         * 6--FF
         * 5--CC
         * 5--bb
         * 4--EE
         * 3--BB
         * 3--aa
         * 2--DD
         * 1--AA
         * */
    }
}