java List 排序问题

来源：互联网发布：淘宝上的川味小吃店铺编辑：程序博客网时间：2024/05/16 07:14

鄙人大概想了三种方式：

1.第一种：借助工具类 Collections

import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.List;public class TestSet {public static void main(String[] ars){Person p1 = new Person("a", 20);List<Person> persons = new ArrayList<Person>();persons.add(new Person("b", 20));persons.add(new Person("a", 20));persons.add(new Person("c", 21));persons.add(new Person("d", 19));persons.add(new Person("e", 19));persons.add(new Person("f", 22));persons.add(new Person("g", 23));persons.add(new Person("h", 18));persons.add(new Person("i", 24));Collections.sort(persons,new Comparator<Person>(){@Overridepublic int compare(Person o1, Person o2) {return o1.getAge()==o2.getAge() ? o2.getName().compareTo(o1.getName()):o2.age-o1.age;}});for (Person p :persons) {System.out.println(p.getAge()+":"+p.getName());}}}class Person{String name ;int age ;public Person(String name ,int age){this.name = name;this.age  = age ;}public int getAge() {return age;}public String getName() {return name;}}

2:将List 转换数组排序然后在转换List

import java.util.ArrayList;import java.util.Arrays;import java.util.Comparator;import java.util.List;public class TestSet {public static void main(String[] ars){Person p1 = new Person("a", 20);List<Person> persons = new ArrayList<Person>();persons.add(new Person("b", 20));persons.add(new Person("a", 20));persons.add(new Person("c", 21));persons.add(new Person("d", 19));persons.add(new Person("e", 19));persons.add(new Person("f", 22));persons.add(new Person("g", 23));persons.add(new Person("h", 18));persons.add(new Person("i", 24));Person[] pary = new Person[persons.size()];pary =persons.toArray(pary);Arrays.sort(pary, new Comparator<Person>(){@Overridepublic int compare(Person o1, Person o2) {return o1.getAge()==o2.getAge() ? o2.getName().compareTo(o1.getName()):o2.age-o1.age;}});persons = Arrays.asList(pary);for (Person p :persons) {System.out.println(p.getAge()+":"+p.getName());}}}class Person{String name ;int age ;public Person(String name ,int age){this.name = name;this.age  = age ;}public int getAge() {return age;}public String getName() {return name;}}

3.利用ListIterator :

import java.util.ArrayList;import java.util.Arrays;import java.util.Collections;import java.util.Comparator;import java.util.List;public class TestSet {public static void main(String[] ars){Person p1 = new Person("a", 20);List<Person> persons = new ArrayList<Person>();persons.add(new Person("b", 20));persons.add(new Person("a", 20));persons.add(new Person("c", 21));persons.add(new Person("d", 19));persons.add(new Person("e", 19));persons.add(new Person("f", 22));persons.add(new Person("g", 23));persons.add(new Person("h", 18));persons.add(new Person("i", 24));//方法三Object[] a = persons.toArray();Arrays.sort(a,new Comparator<Object>(){@Overridepublic int compare(Object o1, Object o2) {Person p1 = (Person)o1;Person p2 = (Person)o2;return p1.getAge()==p2.getAge() ? p2.getName().compareTo(p1.getName()):p2.age-p1.age;}});java.util.ListIterator<Person> li = persons.listIterator();for (int i = 0; i < a.length; i++) {li.next();li.set((Person) a[i]);}for (Person p :persons) {System.out.println(p.getAge()+":"+p.getName());}}}class Person{String name ;int age ;public Person(String name ,int age){this.name = name;this.age  = age ;}public int getAge() {return age;}public String getName() {return name;}}

此处，不用多说，如果排序规则不同，修改Comparator的比较逻辑即可

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