coding++：对List中每个对象元素按时间顺序排序

需求： 需要对List中的每个User按照birthday顺序排序，时间由小到大排列。

package com.tree.ztree_demo.orderby;

import java.text.SimpleDateFormat;
import java.util.*;

public class ListSort {

    public static class UserBean {
        private String id;
        private String birthday;

        public String getId() {
            return id;
        }

        public void setId(String id) {
            this.id = id;
        }

        public String getBirthday() {
            return birthday;
        }

        public void setBirthday(String birthday) {
            this.birthday = birthday;
        }
    }

    public static void main(String[] args) {
        List<UserBean> list = new ArrayList<UserBean>();
        UserListGenerate(list);
        System.out.println("********排序前*******");
        for (UserBean user : list) {
            System.out.println(user.getBirthday());
        }

        ListSort(list);
        System.out.println("******排序后*****");
        for (UserBean user : list) {
            System.out.println(user.getBirthday());
        }
    }

    private static void UserListGenerate(List<UserBean> list) {
        UserBean user1 = new UserBean();
        UserBean user2 = new UserBean();
        UserBean user3 = new UserBean();
        user1.setId("zhagnsan");
        user1.setBirthday("1980/11/01");

        user2.setId("lisi");
        user2.setBirthday("1981/12/01");

        user3.setId("wangwu");
        user3.setBirthday("1980/12/01");

        list.add(user1);
        list.add(user2);
        list.add(user3);
    }

    private static void ListSort(List<UserBean> list) {
        Collections.sort(list, new Comparator<UserBean>() {
            @Override
            public int compare(UserBean o1, UserBean o2) {
                SimpleDateFormat format = new SimpleDateFormat("yyyy/MM/dd");
                try {
                    Date dt1 = format.parse(o1.getBirthday());
                    Date dt2 = format.parse(o2.getBirthday());
                    if (dt1.getTime() < dt2.getTime()) {
                        return 1;
                    } else if (dt1.getTime() > dt2.getTime()) {
                        return -1;
                    } else {
                        return 0;
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
                return 0;
            }
        });
    }
}