java给list列表的对象属性做字典排序(拼音,数字,中文,英文)

解释要做什么:

一个list列表,List list = new ArrayList<>();

里面有很多学生,属性name的内容为:bb,aa,cc.

让这个列表输出顺序变成,aa,bb,cc,看起来跟字典一样好查。

贴代码:

package com.example.practice;

import model.Student;

import java.text.Collator;
import java.util.*;

/**
 * @author : null
 * @date : 2018/11/20
 * @description:
 */
public class StringNull {
    public static void main(String[] args) {
        Student student = new Student();
        List list = new ArrayList<>();
        student.setName("波比");
        list.add(student);
        Student student4 = new Student();
        student4.setName("治安");
        list.add(student4);
        Student student3 = new Student();
        student3.setName("啊啊");
        list.add(student3);
        Student student2 = new Student();
        student2.setName("这个");
        list.add(student2);
        Student student99 = new Student();
        student99.setName(null);
        list.add(student99);
        Student student1 = new Student();
        student1.setName("啊波");
        list.add(student1);
        Student student88 = new Student();
        student88.setName("a波");
        list.add(student88);
        Student student89 = new Student();
        student89.setName("12");
        list.add(student89);
        Student student90 = new Student();
        student90.setName(null);
        list.add(student90);

        for (Student student5 : list) {
            System.out.println(student5.getName());
        }
        Collections.sort(list, new Comparator() {
            @Override
            public int compare(Student o1, Student o2) {
                //这里俩个是对属性判null处理,为null的都放到列表最下面
                if (null==o1.getName()){
                    return 1;
                }
                if (null==o2.getName()){
                    return -1;
                }
                return Collator.getInstance(Locale.CHINESE).compare(o1.getName(),o2.getName());
            }
        });
        System.out.println("输出排序后+++++++++++++++++++++++++++++++");
        for (Student student5 : list) {
            System.out.println(":::"+student5.getName());
        }
    }
}

输出结果:

波比
治安
啊啊
这个
null
啊波
a波
12
null
输出排序后+++++++++++++++++++++++++++++++
:::12
:::a波
:::啊啊
:::啊波
:::波比
:::这个
:::治安
:::null
:::null

简洁点:其中主要的就是这一段

Collections.sort(list, new Comparator() {
            @Override
            public int compare(Student o1, Student o2) {
                //这里俩个是对属性判null处理,为null的都放到列表最下面
                if (null==o1.getName()){
                    return 1;
                }
                if (null==o2.getName()){
                    return -1;
                }
                return Collator.getInstance(Locale.CHINESE).compare(o1.getName(),o2.getName());
            }
        });

里面的compare(target,source)方法,

1.前面的值target大返回正值,

2.相等返回0,

3.小于后面的source返回负值。

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