班级学生排队,男生按照身高从低到高排一队,女生,按照姓名从小到大排一队(使用接口和匿名内部类)
package homework;

import java.sql.Connection;
import java.util.Arrays;

/*
班级学生排队,男生按照身高从低到高排一队,女生,按照姓名从小到大排一队(使用接口和匿名内部类)

分析:
接口,数组,枚举,匿名内部类,Arrrys工具类,String的方法

实现过程:
1.分组
按照性别分成男队和女队
2.排序
使用接口制定对应的规则分别实现男队和女队的排序

只要是从几个固定的值中取出一个,我们可以采用在接口中创建属性的方法,例如当前的Constant.java中的接口.


思想理解:
在进行代码编写时,不能乱使用面向对象,原则:谁的活儿谁干,不是你的活儿不要干.
 */
public class Demo1 {
    public static void main(String[] args) {
        Student[][] students = test1();
        test2(students[0]);
        test3(students[1]);
    }

    //1.分组
    public static Student[][]  test1(){
        //组织数据
        Student[] students = {
                new Student("zhangsan",170.0,Gender.Male),
                new Student("zhangfei",180.0,Gender.Male),
                new Student("zhaoyun",174.0,Gender.Male),
                new Student("guanyu",190.0,Gender.Male),
                new Student("liubei",167.0,Gender.Male),
                new Student("caocao",185.0,Gender.Male),
                new Student("yuanshao",171.0,Gender.Male),
                new Student("yuanshu",172.0,Gender.Male),
                new Student("zhouyu",174.0,Gender.Male),
                new Student("huanggai",182.0,Gender.Male),
                new Student("xiaoqiao",151.0,Gender.Female),
                new Student("daqiao",153.0,Gender.Female),
                new Student("diaochan",171.0,Gender.Female),
                new Student("sunshangxiang",163.0,Gender.Female),
                new Student("huangyueying",169.0,Gender.Female)
        };

        //分组
        //男队
        Student[] stu_males = new Student[students.length];
        //女队
        Student[] stu_females = new Student[students.length];

        //设置男队的标识
        int x = 0;
        //女队的标识
        int y = 0;
        for (int i = 0; i < students.length; i++) {
            Student student = students[i];
            if (student.getGender() == Gender.Male){
                stu_males[x] = student;
                x++;
            }else {
                stu_females[y] = student;
                y++;
            }
        }
        Student[] new_Stu_Males = Arrays.copyOf(stu_males,x);
        Student[] new_Stu_Females = Arrays.copyOf(stu_females,y);

        System.out.println(Arrays.toString(new_Stu_Males));
        System.out.println(Arrays.toString(new_Stu_Females));

        return new Student[][]{new_Stu_Males,new_Stu_Females};
    }
    //2.给男生排序---身高
    public static void test2(Student[] males){
        //第一种方法:先创建一个独立的给男生按照身高比较的比较器,再把比较器交给queue方法
        ComWithMale comWithMale = new ComWithMale();
        ArrayTools.queue(males,comWithMale);
        //第二种:直接使用匿名内部类,编写比较的规则-男生按照身高比较,再交给queue方法
//        ArrayTools.queue(males, new MyComparator() {
//            @Override
//            public int compare(Object o1, Object o2) {
//               //容错处理
//                //不是学生类
//                if (!(o1 instanceof Student)){
//                    //抛出异常
//                    throw  new ClassCastException("当前的不是Student类");
//                }
//                if (!(o2 instanceof Student)){
//                    //抛出异常
//                    throw  new ClassCastException("当前的不是Student类");
//                }
//
//                //向下转型
//                Student s1 = (Student) o1;
//                Student s2 = (Student) o2;
//
//                //按照身高比
//                return (int)Math.ceil(s1.getHeight()-s2.getHeight());
//            }
//        });
        System.out.println("排序后:"+Arrays.toString(males));
    }
    //3.给女生排序---姓名
    public static void  test3(Student[] females){
        ArrayTools.queue(females, new MyComparator() {
            @Override
            //自己写按照姓名比较
            public int compare(Object o1, Object o2) {
                //               //容错处理
                //不是学生类
                if (!(o1 instanceof Student)){
                    //抛出异常
                    throw  new ClassCastException("当前的不是Student类");
                }
                if (!(o2 instanceof Student)){
                    //抛出异常
                    throw  new ClassCastException("当前的不是Student类");
                }

                //向下转型
                Student s1 = (Student) o1;
                Student s2 = (Student) o2;

                //按照姓名比较
                return s1.getName().compareTo(s2.getName());
            }
        });

        System.out.println("排序后:"+Arrays.toString(females));
    }
}

//创建一个用于比较学生的类-确定比较男生--按照身高比--比较器
class ComWithMale implements MyComparator{
    @Override
    public int compare(Object o1, Object o2) {
        //               //容错处理
                //不是学生类
                if (!(o1 instanceof Student)){
                    //抛出异常
                    throw  new ClassCastException("当前的不是Student类");
                }
                if (!(o2 instanceof Student)){
                    //抛出异常
                    throw  new ClassCastException("当前的不是Student类");
                }

                //向下转型
                Student s1 = (Student) o1;
                Student s2 = (Student) o2;

                //按照身高比
                double v = s1.getHeight()-s2.getHeight();
                if (v>=0){
                    return (int)Math.ceil(v);
                }else {
                    return (int)Math.floor(v);
                }

    }
}

//创建表示性别的枚举
//表示可以取几个固定值的地方
//枚举是在高版本的jdk中替换接口属性(符号常量)的功能.
enum Gender{
    Male,Female
}

//建立学生类
class Student{
    private String name;
    private double height;
    //这里使用的是通过接口设置的符号常量
    //private int sex = Constant.SEX_MALE;
    //通过枚举设置的常量
    private Gender gender;

    public String getName() {
        return name;
    }

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

    public double getHeight() {
        return height;
    }

    public void setHeight(double height) {
        this.height = height;
    }

    public Gender getGender() {
        return gender;
    }

    public void setGender(Gender gender) {
        this.gender = gender;
    }

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

    public Student(){}
    public Student(String name, double height, Gender gender) {
        this.name = name;
        this.height = height;
        this.gender = gender;
    }
}

package homework;

public class ArrayTools {
    //排序
    public static void queue(Student[] students,MyComparator comparator){
        for (int i = 0; i < students.length-1; i++) {
            for (int j = 0; j < students.length-i-1; j++) {
                //按照身高从低到高
                if (comparator.compare(students[j],students[j+1])>0){
                    //交换的是学生
                    Student temp = students[j];
                    students[j] = students[j+1];
                    students[j+1] = temp;
                }
            }
        }
    }
}

package homework;

public interface MyComparator {
    /*
    方法:比较的是任意两个学生
    返回值:int型,可以表示正,负,0
    正:表示前面的大于后面
    负:后面的大于前面的
    0:前和后相等
     */
    public int compare(Object o1,Object o2);
}