java中如何实现对类的对象进行排序

发布于 2020-12-30|标签java
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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接口,而在排序时使用Collections.sort(List, Comparator)方法,并实现其中的Comparator接口。先创建一个简单的学生类: ```java 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接口进行排序 ```java public class Student implements Comparable{ 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接口来实现排序 ```java public class Client { public static void main(String[] args){ List 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() { @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()); } } } ``` 原文地址: https://www.php.cn/java-article-438306.html
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