java_章节作业

第1题

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package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/19 version:1.0
 */
public class Homework01 {
    public static void main(String[] args) {

        //初始化Person对象数组，有3个Person对象；
        Person[] persons = new Person[3];
        persons[0] = new Person("tom", 87, "医生");
        persons[1] = new Person("jack", 28, "老师");
        persons[2] = new Person("smith", 56, "护士");

        Person temp = null;
        for (int i = 0; i < persons.length-1; i++) {
            for (int j = 0; j < persons.length - 1 - i; j++) {
                if(persons[j].getAge() > persons[j+1].getAge()){
                    temp = persons[j];
                    persons[j] = persons[j+1];
                    persons[j+1] = temp;
                }
            }

        }

        //输出结果
        for (int i = 0; i < persons.length; i++) {
            System.out.println(persons[i].toString());
        }
    }

    static class Person {
        private String name;
        private int age;
        private String job;

        public Person(String name, int age, String job) {
            this.name = name;
            this.age = age;
            this.job = job;
        }

        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;
        }

        public String getJob() {
            return job;
        }

        public void setJob(String job) {
            this.job = job;
        }

        @Override
        public String toString() {
            return "Person{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    ", job='" + job + '\'' +
                    '}';
        }
    }
}

第2题

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第3题

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Teacher类

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/20 version:1.0
 */
public class Teacher {
    private String name;
    private int age;
    private String post;
    private double salary;
    //这里需要我们增加一个工资级别
    private double grade;

    public Teacher(String name, int age, String post, double salary, double grade) {
        this.name = name;
        this.age = age;
        this.post = post;
        this.salary = salary;
        this.grade = grade;
    }

    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;
    }

    public String getPost() {
        return post;
    }

    public void setPost(String post) {
        this.post = post;
    }

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }

    public double getGrade() {
        return grade;
    }

    public void setGrade(double grade) {
        this.grade = grade;
    }

    public void introduce() {
        System.out.println("姓名：" + name + " 年龄：" + age + " 职称：" + post + " 基本工资：" + salary + " 工资级别：" + grade);
    }
}

Professor类

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/20 version:1.0
 */
public class Professor extends Teacher {

    public Professor(String name, int age, String post, double salary, double grade) {
        super(name, age, post, salary, grade);
    }

    @Override
    public void introduce() {
        System.out.println("这是教授的基本信息");
        super.introduce();
    }
}

Homework3

package com.hspedu.homework;

import jdk.nashorn.internal.ir.CallNode;


public class Homework03 {
    public static void main(String[] args) {
        Professor professor = new Professor("林老师",30,"高级职称",30000,1.3);
        professor.introduce();
    }
}

第4题

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Worker类

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/20 version:1.0
 */
public class Worker {
    private String name;
    private double salary;
    private int day;
    // 需要一个等级
    private double garde;

    public Worker(String name, double salary, int day, double garde) {
        this.name = name;
        this.salary = salary;
        this.day = day;
        this.garde = garde;
    }

    public String getName() {
        return name;
    }

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

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }

    public int getDay() {
        return day;
    }

    public void setDay(int day) {
        this.day = day;
    }

    public double getGarde() {
        return garde;
    }

    public void setGarde(double garde) {
        this.garde = garde;
    }

    public void print() {
        System.out.println(name + " 工资为：" + salary*day*garde);
    }
}

PTworker类

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/20 version:1.0
 */
public class PTworker extends Worker{
    public PTworker(String name, double salary, int day, double garde) {
        super(name, salary, day, garde);
    }

    @Override
    public void print() {
        System.out.print("普通员工");
        super.print();
    }
}

MAworker类

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/20 version:1.0
 */
public class MAworker extends Worker{
    //特有属性
    private double bonus;

    public MAworker(String name, double salary, int day, double garde) {
        super(name, salary, day, garde);
    }

    public double getBonus() {
        return bonus;
    }

    public void setBonus(double bonus) {
        this.bonus = bonus;
    }

    @Override
    public void print() {
        System.out.println("部门经理" + getName()+" 工资为：" + (bonus+getSalary()*getDay()*getGarde()));
    }
}

Homework04类

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/20 version:1.0
 */
public class Homework04 {
    public static void main(String[] args) {
        PTworker jack = new PTworker("jack", 260, 20, 1.0);
        MAworker tom = new MAworker("tom", 500, 25, 1.2);
        //设置奖金
        tom.setBonus(3000);
        jack.print();
        tom.print();
    }
}

第5题

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Yugong类

package com.hspedu.homework.homework5;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Yungong {
    private String name;
    private double sal;

    //带薪月数
    private int salMonth = 12;



    public Yungong(String name, double sal) {
        this.name = name;
        this.sal = sal;
    }

    public String getName() {
        return name;
    }

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

    public double getSal() {
        return sal;
    }

    public void setSal(double sal) {
        this.sal = sal;
    }

    public int getSalMonth() {
        return salMonth;
    }

    public void setSalMonth(int salMonth) {
        this.salMonth = salMonth;
    }

    //打印工资
    public void print_() {
        System.out.println(name + " 的全年工资为：" + (salMonth * sal));
    }
}

Worker

package com.hspedu.homework.homework5;

import java.io.StringReader;


public class Worker extends Yungong{
    public Worker(String name, double sal) {
        super(name, sal);
    }

    //打印工资
    @Override
    public void print_() {
        super.print_();
    }
}

Peasant

package com.hspedu.homework.homework5;


public class Peasant extends Yungong{
    public Peasant(String name, double sal) {
        super(name, sal);
    }

    //打印工资
    @Override
    public void print_() {
        super.print_();
    }
}

Teacher类

package com.hspedu.homework.homework5;

import java.util.SplittableRandom;


public class Teacher extends Yungong{

    //一年上的多少节课
    private double classDay;
    //课时费
    private double classSal;

    public Teacher(String name, double sal) {
        super(name, sal);
    }

    public double getClassDay() {
        return classDay;
    }

    public void setClassDay(double classDay) {
        this.classDay = classDay;
    }

    public double getClassSal() {
        return classSal;
    }

    public void setClassSal(double classSal) {
        this.classSal = classSal;
    }

//打印工资

    @Override
    public void print_() {
        System.out.println(getName() + " 全年工资为：" + (getSalMonth() * getSal() + getClassDay() * getClassSal()));
    }
}

Scientist

package com.hspedu.homework.homework5;

import com.sun.xml.internal.ws.api.model.wsdl.WSDLOutput;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Scientist extends Yungong{

    private double bonus;

    public Scientist(String name, double sal) {
        super(name, sal);
    }

    public double getBonus() {
        return bonus;
    }

    public void setBonus(double bonus) {
        this.bonus = bonus;
    }

    //打印工资

    @Override
    public void print_() {
        System.out.println(getName() + " 全年工资为：" + (getSalMonth() * getSal() + getBonus()));
    }
}

Waiter

package com.hspedu.homework.homework5;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Waiter extends Yungong{
    public Waiter(String name, double sal) {
        super(name, sal);
    }
    //打印工资
    @Override
    public void print_() {
        super.print_();
    }
}

测试类Homework05

package com.hspedu.homework.homework5;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Homework05 {
    public static void main(String[] args) {
        Worker jack = new Worker("jack", 1000);
        Peasant tom = new Peasant("tom", 500);

        Teacher sim = new Teacher("sim", 3500);
        sim.setClassDay(300);
        sim.setClassSal(1000);
        Scientist scient = new Scientist("scient", 6000);
        scient.setBonus(10000);

        Waiter wait = new Waiter("wait", 2000);


        jack.print_();
        tom.print_();
        sim.print_();
        scient.print_();
        wait.print_();


    }
}

第6题

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super从父类（不局限于直接父类）开始，不找本类；this从本类开始查找，再找父类

super（父类对象）可以访问父类及以上，除了 private修饰、静态、覆盖的成员
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this访问不了父类中被重写(或者说覆盖)的属性和方法
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第7题

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代码

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Homework07 {
}

class Test{
    String name = "Rose";
    Test() {
        System.out.println("Test");//(1)Test
    }
    Test(String name) {
        this.name = name; //将Test类的 name 修改为 john
    }
}

class Demo extends Test{
    String name = "Jack";
    Demo() {
        super();
        System.out.println("Demo");//(2)Demo
    }
    Demo(String s) {
        super(s); //s == john
    }
    public void test() {
        System.out.println(super.name);//(3)Rose (5)john
        System.out.println(this.name);//(4)Jack  (6) Jack
    }

    //程序从这里开始执行
    public static void main(String[] args) {
        new Demo().test();
        new Demo("john").test();
    }
}

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第8题

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BankAccount

package com.hspedu.homework;

import com.sun.corba.se.impl.ior.ObjectAdapterIdNumber;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class BankAccount {//父类
    private double balance; //余额
    public BankAccount(double initialBalance) {
        this.balance = initialBalance;
    }
    //存款
    public void deposit(double amount) {
        balance += amount;
    }
    //取款
    public void withdraw(double amount) {
        balance -= amount;
    }

    public double getBalance() {
        return balance;
    }

    public void setBalance(double balance) {
        this.balance = balance;
    }
}

CheckingAccount

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class CheckingAccount extends BankAccount {


    public CheckingAccount(double initialBalance) {
        super(initialBalance);
    }

    @Override
    public void deposit(double amount) {
        super.deposit(amount-1);
        //1块钱入银行的账户
    }

    @Override
    public void withdraw(double amount) {
        super.withdraw(amount+1);
        //1块钱入银行的账户
    }
}

SavingsAccount

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class SavingsAccount extends BankAccount {
    private  int count = 3;
    private double rate = 0.01; //利率

    public SavingsAccount(double initialBalance) {
        super(initialBalance);
    }

    public int getCount() {
        return count;
    }

    public void setCount(int count) {
        this.count = count;
    }

    public double getRate() {
        return rate;
    }

    public void setRate(double rate) {
        this.rate = rate;
    }

    //每个月初，统计上个月的利息，并重置 减免手续费次数的值 count = 3;
    public void  earnMonthlyInterest(){
        count = 3;
        super.deposit(getBalance() * rate);

    }
    //重写存款方法
    @Override
    public void deposit(double amount) {//存款
        //判断是否还可以免手续费
        if(count > 0){
            super.deposit(amount);
        } else {
            super.deposit(amount-1);
        }
        count--; //减去一次
    }

    //重写 取款方法
    @Override
    public void withdraw(double amount) { //取款
        //判断是否还可以免手续费
        if(count > 0) {
            super.withdraw(amount);  //1块转入银行账户
        } else {
            super.withdraw(amount+1);
        }
        count--; //减去一次
    }
}

Homework08

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Homework08 {
    public static void main(String[] args) {
//        CheckingAccount checkingAccount = new CheckingAccount(1000);
//        checkingAccount.deposit(10);//存10块，-1手续费 1009
//        checkingAccount.withdraw(10);//取10块，-1手续费 998
//
//        System.out.println(checkingAccount.getBalance());

        SavingsAccount savingsAccount = new SavingsAccount(1000);
        savingsAccount.deposit(100);//存款100 免手续费
        savingsAccount.deposit(100);//存款100 免手续费
        savingsAccount.deposit(100);//存款100 免手续费
        System.out.println(savingsAccount.getBalance());//余额 1300
        savingsAccount.deposit(100);//手续费 -1
        System.out.println(savingsAccount.getBalance());//余额 1300+100-1=1399

//      //月初，定时器自动调用一下， earnMonthlyInterest
        savingsAccount.earnMonthlyInterest();//统计利息
        System.out.println(savingsAccount.getBalance());//1399 + 13.99=
        savingsAccount.deposit(100);//存款100 免手续费
        savingsAccount.deposit(100);//存款100 免手续费
        savingsAccount.deposit(100);//存款100 免手续费

    }
}

第9题

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Point

package com.hspedu.homework;


public class Point {
    private double x;
    private double y;

    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }
}

LabeledPoint

package com.hspedu.homework;

import com.hspedu.homework.Point;


public class LabeledPoint extends Point {
    private String label;

    public LabeledPoint( String label,double x, double y) {
        super(x, y);
        this.label = label;
    }
}

Homework09

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Homework09 {
    public static void main(String[] args) {
        new LabeledPoint("Black",1929,230.04);
    }
}

第10题

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Doctor

package com.hspedu.homework;

import javax.print.Doc;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Doctor {
    private String name;
    private int age;
    private String job;
    private char gender;
    private double sal;

    public Doctor(String name, int age, String job, char gender, double sal) {
        this.name = name;
        this.age = age;
        this.job = job;
        this.gender = gender;
        this.sal = sal;
    }

    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;
    }

    public String getJob() {
        return job;
    }

    public void setJob(String job) {
        this.job = job;
    }

    public char getGender() {
        return gender;
    }

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

    public double getSal() {
        return sal;
    }

    public void setSal(double sal) {
        this.sal = sal;
    }

    @Override
    public boolean equals(Object obj) {
        //判断两个比较对象是否相同
        if(this == obj) {
            return true;
        }
        //判断obj 是否是 Doctor类型或其子类
        //过关斩将 校验方式
        if(! (obj instanceof Doctor)){ //不是的话
            return false;
        }

        //这里因为 编译类型是 object，无法访问Doctor属性，
        // 所以需要向下转型
        Doctor doctor = (Doctor)obj;
        return this.name.equals(doctor.name) && this.age == doctor.age && this
                .gender == doctor.gender && this.job.equals(doctor.job) && this.sal == doctor.sal;

    }
}

Homework10

package com.hspedu.homework;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Homework10 {
    public static void main(String[] args) {
        Doctor doctor1 = new Doctor("jack", 20, "医生", '男', 20000);
        Doctor doctor2 = new Doctor("jack", 20, "医生", '男', 20000);
        System.out.println(doctor1.equals(doctor2));//true

    }
}

第11题

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向上转型：父类的引用指向子类的对象

Person  p = new Student();
p.run(); // 能调用父类的run(),实际运行的是子类的run();
p.eat();//能调用父类的eat()，因为子类中没有eat(),所以执行的是父类的eat();

编译看左边（父类），执行看右边

意思就是向上转型只能找到父类方法，运行的时候就得看运行类型怎么说了,如果Student类有相同的方法，那就执行Student类的；如果没有，那就去父类找，有就执行；

向下转型：把指向子类对象的父类引用，转成指向子类对象的子类引用
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第12题

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第13题

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Person

package com.hspedu.homework.homework13;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Person {
    private String name;
    private char sex;
    private int age;

    public Person(String name, char sex, int age) {
        this.name = name;
        this.sex = sex;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public char getSex() {
        return sex;
    }

    public void setSex(char sex) {
        this.sex = sex;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    //玩的方法
    public String play() {
        return name + "爱玩";
    }

    //打印方法
    public String basicInfo() {
        return "性别：" + name + "\n年龄：" + age + "\n性别：" + sex;
    }

    @Override
    public String toString() {
        return "name='" + name + '\'' +
                ", sex=" + sex +
                ", age=" + age +",";
    }
}

Student

package com.hspedu.homework.homework13;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Student extends Person{
    private String stu_id;

    public Student(String name, char sex, int age, String stu_id) {
        super(name, sex, age);
        this.stu_id = stu_id;
    }

    public String getStu_id() {
        return stu_id;
    }

    public void setStu_id(String stu_id) {
        this.stu_id = stu_id;
    }

    public void study() {
        System.out.println("我承诺，我会好好学习");
    }
    @Override
    public String play() {
       return super.play() + "足球";
    }



    //编写一个输出信息的方法,这样体现封装
    public void printInfo() {
        System.out.println("学生的信息：");
        System.out.println(super.basicInfo());
        System.out.println("学号：" + stu_id);
        study();
        System.out.println(play());
    }

    @Override
    public String toString() {
        return "Student{" +super.toString()+
                "stu_id='" + stu_id + '\'' +
                '}';
    }
}

Teacher

package com.hspedu.homework.homework13;

/**
 * @author:寰愬悏瓒�
 * @date:2024/12/21 version:1.0
 */
public class Teacher extends Person{
    private int work_age;

    public Teacher(String name, char sex, int age, int work_age) {
        super(name, sex, age);
        this.work_age = work_age;
    }

    public int getWork_age() {
        return work_age;
    }

    public void setWork_age(int work_age) {
        this.work_age = work_age;
    }

    public void teach(){
        System.out.println("我承诺，我会认真教学");
    }

    @Override
    public String play() {
        return super.play() +"象棋";
    }

    public void printInfo() {
        System.out.println("老师的信息：");
        System.out.println(super.basicInfo());
        System.out.println("工龄：" + work_age);
        teach();
        System.out.println(play());
    }

    @Override
    public String toString() {
        return "Teacher{" + super.toString() +
                "work_age=" + work_age +
                '}';
    }
}

Homework13

package com.hspedu.homework.homework13;



public class Homework13 {
    public static void main(String[] args) {
//        Teacher teacher = new Teacher("张飞", '男', 30, 5);
//        teacher.printInfo();
//        System.out.println("---------------------------");
//
//        Student student = new Student("小明", '男', 15, "00023102");
//        student.printInfo();

        Person[] person= new Person[4];
        person[0] = new Student("tom", '男', 23,"00001");
        person[1] = new Student("ming", '男', 24,"00002");
        person[2] = new Teacher("smith", '女', 30,10);
        person[3] = new Teacher("wujing", '女', 46,20);


        Homework13 homework13 = new Homework13();
        homework13.bubbleSort(person);



        System.out.println("-------------排序后的Person数组------------");
        for (int i = 0; i < person.length; i++) {
            System.out.println(person[i]); //这是，实际上是调用person[i].toString()
        }

        //遍历数组，调用test方法
        System.out.println("==================");
        for (int i = 0; i <person.length; i++) { //遍历多态数组
                homework13.test(person[i]); // test方法去判断是学生还是老师
        }

    }

    //排序方法-冒泡排序
    private void bubbleSort(Person[] person) {
        Person temp  = null;
        //按照年龄从高到低排序
        for (int i = 0; i < person.length-1; i++) {
            for (int j = 0; j < person.length-i-1; j++) {
                if(person[j].getAge() < person[j+1].getAge()){
                    temp = person[j];
                    person[j] = person[j+1];
                    person[j+1] = temp;
                }
            }
        }
    }

    //定义方法，形参为Person类型，功能：调用学生的study或教师的teach方法
    //这里会使用到向下转型和类型判断
    public void test(Person p){
        if(p instanceof Student){ // p 的运行类型如果是Student
            ((Student) p).study();
        } else if(p instanceof Teacher) { // p 的运行类型如果是 Teacher
            ((Teacher) p).teach();
        } else {
            System.out.println("do nothing...");
        }
    }

}