比较器

public class Code_09_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 imlements Comparator<Student>{//继承接口，接口内放置自己定义的想要比较的东西
        @override
        public int compara (Student 01,Student 02){
        return 01.id-02.id;//如果01的值小，减完就是负数；02的值小减完就是正数；相等减完是0
        }
    public static class IdDescendingComparator implements Comparator<Student>{
    @overrid
    public int compare(Student 01,Student 02){
        return 02.id-01.id;//降序排列id
}
    public static class AgeAscendingComparators Comparator<Student>{
    @override
    public int compare (Stuent 01,Student 02){
        return 01.age-02.age;//升序排列age
}
    public static class AgeDescendingComparator implements Comparator<Student>{
    @override
     public int compare(Student 01,Student 02){
        return 02.age-01.age;//降序排列age
}
    public static void printStudents (Student[] Students){//输出函数
    for(Student student : students){
    System.out.println("Name:"+student.name+",Id:"+student.id+".Age:"+student.age);}
    System.out.println("============");}
    public static void main(String[] args){
        Student student1 =new Student("A",1,23);
        Student student2 =new Student("B",2,21);
        Student student3 =new Student("C",3,22);

        //建立数组，把学生1，2，3放进数组
    Student[] students =new Student[]{student3,student2,student1};
     printStudents(students);
     Arrays.sort(students new IdAscendingComparator());//调用系统函数，①添加students有意义情况：数组，自己定义的比较器②单纯调用sort（students）按照内存地址排序（无意义），例如：基础类型根据数值从小到大排序。
     printStudents(students);
     Arrays.sort(students new IdDescendingComparator());
     printStudents(students);
     Arrays.sort(students new AgeScendingComparator());
     printStudents(students);
     Arrays.sort(students new AgeScendingComparator());
     printStudents(students);
      
/*Integer[] arr={3,2,4,1,0}; Arrarys.sort(arr,newMycomp());printArray(arr);*/