java中list<Object[]>、list<Student>、list<Map<String,String>>排序

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1：list<Object[]>的排序

public static void main(String[] args) {// TODO Auto-generated method stubObject[] o1=new Object[4];o1[0]="5";o1[1]="o1";o1[2]="o11";o1[3]="o111";Object[] o2=new Object[4];o2[0]="3";o2[1]="o2";o2[2]="o22";o2[3]="o222";List<Object[]> list=new ArrayList<>();list.add(o1);list.add(o2);

//很明显我们先添加的对象o1，所以先打印o1，

for(inti=0;i<list.size();i++){for(intj=0;j<4;j++){System.out.print(list.get(i)[j]+"  ");}}System.out.println("\n排序后-------");sortList(list);

//排序后：

for(inti=0;i<list.size();i++){for(intj=0;j<4;j++){System.out.print(list.get(i)[j]+"  ");}}

写一个方法

public staticvoid sortList(List<Object[]>ls){Collections.sort(ls,new Comparator<Object[]>() {@Overridepublic int compare(Object[] o1, Object[] o2) {if(Integer.valueOf(o1[0].toString())>Integer.valueOf(o2[0].toString())){return 1;}return -1;}});}

2：//list<Student>排序，主要是正对汉族的排序，按照拼音排序，

首先写一个Student类：

package com.model;public class Student {public Stringname;publicintage;public Student(Stringname,intage){this.name=name;this.age=age;}public void setName(String name){this.name=name;}public String getName(){returnname;}public void setAge(int age){this.age=age;}public int getAge(){returnage;}}

然后在main方法中调用，（这里写的是一个java文件）

Student stu1=new Student("张三",23);Student stu2=new Student("李四",25);List<Student> listStudent=new ArrayList<>();listStudent.add(stu1);listStudent.add(stu2);System.out.println();for(int i=0;i<listStudent.size();i++){System.out.print(listStudent.get(i).getName()+"---"+listStudent.get(i).getAge());}System.out.println("\n排序后");sortListStudent(listStudent);for(int i=0;i<listStudent.size();i++){System.out.print(listStudent.get(i).getName()+"---"+listStudent.get(i).getAge());}

写一个排序方法

public staticvoid sortListStudent(List<Student>ls){Collections.sort(ls,new Comparator<Student>() {@Overridepublic int compare(Student o1, Student o2) {String s1=o1.getName();String s2=o2.getName();if(s1.compareTo(s2)>0){return -1;} return 1;}});}}

结果图：

3：list<Map<String,String>>排序问题：

import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.HashMap;import java.util.List;import java.util.Map;public class MapListSort {    public static void main(String[] args) {        // TODO Auto-generated method stub        List<Map<String,String>> listMap=new ArrayList<>();        Map<String, String> map1=new HashMap<String, String>();        map1.put("map001", "001");        map1.put("map003", "map003");        map1.put("map002", "map002");        Map<String, String> map2=new HashMap<String, String>();        map2.put("map001", "101");        map2.put("map003", "map303");        map2.put("map002", "map202");        //先添加的map2，但是map2中map001的值大于map1中的map001的值。        listMap.add(map2);        listMap.add(map1);                for(int i=0;i<listMap.size();i++){                System.out.print(listMap.get(i).get("map001")+","+listMap.get(i).get("map002")+","+listMap.get(i).get("map003")+"\n");                        }                mapSorts(listMap);                System.out.println("\n排序后：");        for(int i=0;i<listMap.size();i++){            System.out.print(listMap.get(i).get("map001")+","+listMap.get(i).get("map002")+","+listMap.get(i).get("map003")+"\n");    }    }        public static void mapSorts(List<Map<String,String>> map){        Collections.sort(map,new Comparator<Map<String,String>>() {            @Override            public int compare(Map<String, String> o1, Map<String, String> o2) {                // TODO Auto-generated method stub                if(o1.get("map001").compareTo(o2.get("map001"))>0){                    return 1;                                   }                return -1;            }        });    }}

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