千锋逆战班学习第19天

最新推荐文章于 2020-04-08 21:55:34 发布

原创最新推荐文章于 2020-04-08 21:55:34 发布 · 277 阅读

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CC 4.0 BY-SA版权

智慧源于勤奋伟大出自平凡

模拟java.util.Array.sort工具

public class TestSort {

   public static void main(String[] args) {
       Student[] students = new Student[]{new Student("tom" , 20 , "male" , 90D) ,
               new Student("jack" , 19 , "male" , 91D) , new Student("marry" , 21 , "male" , 90D)};
       Tool.sort(students);//工具的调用者
       for(int i = 0; i < students.length;i++){
           System.out.println(students[i].name + "\t" + students[i].score +"\t" + students[i].age);
       }
   }

}
class Student implements Comparable<Student>{//接口的实现者
   String name;
   int age;
   String sex;
   double score;
   public Student(){}
   public Student(String name, int age, String sex, double score) {
       super();
       this.name = name;
       this.age = age;
       this.sex = sex;
       this.score = score;
   }
   @Override
   public int comparTo(Student stu) {
       if(this.score > stu.score){
           return 1;
       }else if(this.score < this.score){
           return -1;
       }
       else if(this.score == stu.score){
           if(this.age > stu.age){
               return 1;
           }
       }

           return 0;

   }

}

public class Tool <T>{//接口的使用者
   public static void sort(Student[] stu){
       for(int i = 0; i < stu.length - 1;i++){
           Comparable com = (Comparable)stu[i];
           int n = com.comparTo(stu[i+1]);
           if(i > 0){
               Student temp = stu[i];
               stu[i] = stu[i+1];
               stu[i+1] = temp;
           }
       }
   }

}

public interface Comparable<T>{//接口
int comparTo(T stu);

//this.与下一个比较，如果为正数则是升序，如果是负数，则是降序，如果为0，不变

}

调用java.util.Arrays.sort写实现类进行排序

public class TestTeacher {

   public static void main(String[] args) {
       Teacher[] teachers = new Teacher[]{new Teacher("tom" , 28) , new Teacher("jack" , 30) ,
               new Teacher("marry" , 25)};
       java.util.Arrays.sort(teachers);
       for(int i = 0; i < teachers.length;i++){
           System.out.println(teachers[i].name + "\t" + teachers[i].age);
       }

}

}
class Teacher implements Comparable<Teacher>{
   String name;
   int age;
   public Teacher(){}
   public Teacher(String name, int age) {
       super();
       this.name = name;
       this.age = age;
   }
   @Override
   public int compareTo(Teacher t) {
       if(this.age > t.age){
           return 1;
       }
       else if(this.age < t.age){
           return -1;
       }
       return 0;
   }

}

Usb接口来说明耦合度低的好处

public class TestUsb {

   public static void main(String[] args) {
       Computer computer = new Computer();
       Fan fan = new Fan();
       Light light = new Light();
       computer.on(fan);
       System.out.println("-------------------");
       computer.on(fan,light);

}

}
class Computer{
Usb u1;
Usb u2;

   public void on(Usb u){
       this.u1 = u;
       u1.service();
   }
   public void on(Usb u1 , Usb u2){
       this.u1 = u1;
       this.u2 = u2;
       u1.service();;
       u2.service();
   }

}
interface Usb{
   void service();
}
class Fan implements Usb{