java比较器的简单使用

本文主要是介绍java比较器的简单使用，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

package class03P;

import java.util.Arrays;
import java.util.Comparator;
import java.util.PriorityQueue;

public class Code03P_Comparator {
    public static class Student{
        public String name;
        public int id;
        public int age;

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

    public static class IdAscendingComparator implements Comparator<Student> {
        @Override
        public int compare(Student o1, Student o2){
            return o1.id - o2.id;
        }
    }

    public static class IdDescendingComparator implements Comparator<Student>{
        @Override
        public int compare(Student o1, Student o2){
            return o2.id - o1.id;
        }
    }
    
    public static class AgeAscendingComparator implements Comparator<Student> {

        @Override
        public int compare(Student o1, Student o2) {
            return o1.age - o2.age;
        }

    }

    public static class AgeDescendingComparator implements Comparator<Student> {

        @Override
        public int compare(Student o1, Student o2) {
            return o2.age - o1.age;
        }

    }
    
    public static void printArray(Student[] students){
        for (Student student :
                students) {
            System.out.println("Name : " + student.name + ", Id : " + student.id + " , Age : " + student.age);
        }
    }

    public static class MyComp implements Comparator<Integer>{
        @Override
        public int compare(Integer o1, Integer o2){
            return o2 - o1;
        }
    }

    public static void main(String[] args){
        Student student1 = new Student("A", 2, 33);
        Student student2 = new Student("B", 3, 21);
        Student student3 = new Student("C", 1, 22);

        Student[] students = new Student[] { student1, student2, student3};

        Arrays.sort(students, new IdAscendingComparator());
        printArray(students);
        System.out.println("=======================================");

        Arrays.sort(students, new IdDescendingComparator());
        printArray(students);
        System.out.println("=======================================");

        Arrays.sort(students, new AgeAscendingComparator());
        printArray(students);
        System.out.println("=======================================");

        Arrays.sort(students, new AgeAscendingComparator());
        printArray(students);
        System.out.println("=======================================");
        System.out.println("=======================================");
        System.out.println("=======================================");
        System.out.println("=======================================");
        System.out.println("=======================================");

        PriorityQueue<Student> maxHeapBasedAge = new PriorityQueue<>(new AgeDescendingComparator());
        maxHeapBasedAge.add(student1);
        maxHeapBasedAge.add(student2);
        maxHeapBasedAge.add(student3);
        while(maxHeapBasedAge.isEmpty()){
            Student student = maxHeapBasedAge.poll();
            System.out.println("Name : " + student.name + ", Id : " + student.id + " , Age : " + student.age);
        }
        System.out.println("=======================================");
    }
}

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