java中如何实现对类的对象进行排序

我们需要对类按照类中的某一个属性(或者多个属性)来对类的对象进行排序,有两种方法可以实现,一种方法是类实现Comparable<T>接口,然后调用Collections.sort(List)方法进行排序,另一种方法是类不实现Comparable<T>接口,而在排序时使用Collections.sort(List, Comparator<T>)方法,并实现其中的Comparator<T>接口。

先创建一个简单的学生类:

public class Student {
 private String name;
 private int age;
 public Student() {}

 public Student(String name, int age) {
 this.name = name;
 this.age = age;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public int getAge() {
 return age;
 }

 public void setAge(int age) {
 this.age = age;
 }
}

1、通过类实现Comparable<T>接口进行排序

public class Student implements Comparable<Student>{

 private String name;
 private int age;
 public Student() {}

 public Student(String name, int age) {
 this.name = name;
 this.age = age;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public int getAge() {
 return age;
 }

 public void setAge(int age) {
 this.age = age;
 }

 /**
 * 将对象按姓名字典序升序排序
 * @param o
 * @return
 */

 @Override

 public int compareTo(Student o) {
 return this.name.compareTo(o.getName());
 }

 @Override
 public String toString() {
 return "Student{" +
  "name='" + name + '\'' +
  ", age=" + age +
  '}';
 }

}

2、通过在Collections.sort()方法中实现Comparable<T>接口来实现排序

public class Client {

 public static void main(String[] args){
 List<Student> students = new ArrayList<>();
 students.add(new Student("a", 18));
 students.add(new Student("c", 19));
 students.add(new Student("b", 20));

 Collections.sort(students, new Comparator<Student>() {
  @Override
  public int compare(Student o1, Student o2) {
  return o1.getAge()>o2.getAge()? -1:(o1.getAge()==o2.getAge()? 0:1);
  }
 });

 for(Student student:students){
  System.out.println(student.toString());
 }
 }
}

以上就是java中实现对类的对象进行排序的详细内容,感谢大家对亿速云的支持。