Java List集合排序實現方法解析
阿新 • • 發佈:2020-01-07
這篇文章主要介紹了Java List集合排序實現方法解析,文中通過示例程式碼介紹的非常詳細,對大家的學習或者工作具有一定的參考學習價值,需要的朋友可以參考下
1.使用 Collections 工具類中的 sort() 方法
引數不同:
void sort(List list) 在自定義類User裡面實現Comparable<User>介面,並重寫抽象方法compareTo(Student o);
void sort(List list,Comparator c) 第二個引數為了省事,可以直接使用匿名內部類
public class User implements Comparable<User>{ private int score; private int age; public User(int score,int age){ super(); this.score = score; this.age = age; } public int getScore() { return score; } public void setScore(int score) { this.score = score; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public int compareTo(User o) { int i = this.getAge() - o.getAge();//先按照年齡排序 if(i == 0){ return this.score - o.getScore();//如果年齡相等了再用分數進行排序 } return i; } } public static void main(String[] args) { List<User> users = new ArrayList<User>(); users.add(new User(78,26)); users.add(new User(67,23)); users.add(new User(34,56)); users.add(new User(55,23)); Collections.sort(users); for(User user : users){ System.out.println(user.getScore() + "," + user.getAge()); } }
public class Students { private int age; private int score; public Students(int age,int score){ super(); this.age = age; this.score = score; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public int getScore() { return score; } public void setScore(int score) { this.score = score; } } public static void main(String[] args) { List<Students> students = new ArrayList<Students>(); students.add(new Students(23,100)); students.add(new Students(27,98)); students.add(new Students(29,99)); students.add(new Students(29,98)); students.add(new Students(22,89)); Collections.sort(students,new Comparator<Students>() { @Override public int compare(Students o1,Students o2) { int i = o1.getScore() - o2.getScore(); if(i == 0){ return o1.getAge() - o2.getAge(); } return i; } }); for(Students stu : students){ System.out.println("score:" + stu.getScore() + ":age" + stu.getAge()); } }
2.直接使用list.sort()方法,傳入實現Comparator介面的實現類的例項,為了省事直接傳入匿名內部類
public class Students { private int age; private int score; public Students(int age,int score){ this.age = age; this.score = score; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public int getScore() { return score; } public void setScore(int score) { this.score = score; } } public static void main(String[] args) { List<Students> students = new ArrayList<Students>(); students.add(new Students(23,100)); students.add(new Students(27,98)); students.add(new Students(29,99)); students.add(new Students(29,98)); students.add(new Students(22,89)); students.sort(new Comparator<Students>() { @Override public int compare(Students o1,Students o2) { int i = o1.getScore() - o2.getScore(); if (i == 0) { return o1.getAge() - o2.getAge(); } return i; } }); for (Students stu : students) { System.out.println("score:" + stu.getScore() + ":age" + stu.getAge()); } }
以上就是本文的全部內容,希望對大家的學習有所幫助,也希望大家多多支援我們。