Java List集合排序实现方法解析

这篇文章主要介绍了Java List集合排序实现方法解析,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

1.使用 Collections 工具类中的 sort() 方法

参数不同:

void sort(List list) 在自定义类User里面实现Comparable<User>接口,并重写抽象方法compareTo(Student o);

void sort(List list, Comparator c) 第二个参数为了省事,可以直接使用匿名内部类

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();//先按照年龄排序

if(i == 0){

return this.score - o.getScore();//如果年龄相等了再用分数进行排序

}

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,传入实现Comparator接口的实现类的实例,为了省事直接传入匿名内部类

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());

  }

}

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