Java作业题记录

1.定义一个Person类{name, age, job},初始化Person对象数组，有3个person对象，并按照 age 从大到小进行排序,提示，使用冒泡排序Homework01.java

难点1：初始化数组Person[] people = new Person[3];

难点2：获得年龄数据people[j].getAge()

难点3：System.out.println(people[i]); //默认调用对象toString 方法

package com.hspedu.extend_.exercise.OOP;public class HomeWork01 {public static void main(String[] args) {Person[] people = new Person[3];people[0] = new Person("小莫", 19, "学生");people[1] = new Person("小季", 20, "学生");people[2] = new Person("小林", 19, "学生");for (int i = 0; i < people.length; i++) {System.out.println(people[i]);  //默认调用对象toString 方法}Person tmp = null; //因为要交换的是Person 类型的对象//冒泡排序for (int i = 0; i < people.length - 1; i++) {for (int j = 0; j < people.length - 1 - i; j++) {//年龄从大到小排序if(people[j].getAge() < people[j+1].getAge()) {tmp = people[j];people[j] = people[j+1];people[j+1] = tmp;}}}//排序后System.out.println("======排序后=====");for (int i = 0; i < people.length; i++) {System.out.println(people[i]);  //默认调用对象toString 方法}}
}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 String getJob() {
//        return job;
//    }
//
//    public void setJob(String job) {
//        this.job = job;
//    }public int getAge() {return age;}public void setAge(int age) {this.age = age;}@Overridepublic String toString() {return "Person{" +"name='" + name + '\'' +", age=" + age +", job='" + job + '\'' +'}';}
}

结果：

Person{name='小莫', age=19, job='学生'}
Person{name='小季', age=20, job='学生'}
Person{name='小林', age=19, job='学生'}
======排序后=====
Person{name='小季', age=20, job='学生'}
Person{name='小莫', age=19, job='学生'}
Person{name='小林', age=19, job='学生'}

2.写出四种访问修饰符和各自的访问权限Homework02.java

访问级别	访问控制修饰符	同类	同包	子类	不同包
公开	public	√	√	√	√
受保护	protected	√	√	√	×
默认	没有修饰符	√	√	×	×
私有	private	√	×	×	×

3.编写老师类 Homework03.java

(1)要求有属性“姓名name”，“年龄age”，“职称post”，“基本工资salary”

(2)编写业务方法，introduce()，实现输出一个教师的信息。
(3) 编写教师类的三个子类:教授类(Professor )、副教授类、讲师类。工资级别分别为:教授为1.3、副教授为1.2、讲师类1.1。在三个子类里面都重写父类的introduce()方法。

(4)定义并初始化一个老师对象，调用业务方法，实现对象基本信息的后台打印.

难点1：明确知晓在子类中无法得到父类的私有信息

难点2：知晓子类建构造器后要用super（），访问父类构造器

难点3：

即使一个方法没有定义任何参数，它仍然可以访问和操作类中的字段（属性）或全局变量。这些变量可以在方法被调用之前或之后定义，并且可以在方法内部使用。

此外，如果方法没有参数，但需要使用一些值进行操作，你可以在方法内部定义局部变量。这些变量只能在方法内部使用，并且它们的生命周期仅限于该方法的执行期间

package com.hspedu.extend_.exercise.OOP;public class HomeWork03 {public static void main(String[] args) {Professor professor = new Professor("贾宝玉", 30, "高级职称", 30000, 1.3);professor.introduce();}
}class Teacher {private String name;private int age;private String post;private double salary;//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);}}

package com.hspedu.extend_.exercise.OOP;
public class Professor extends Teacher{public Professor(String name, int age, String post, double salary, double grade) {super(name, age, post, salary, grade);}@Overridepublic void introduce() {System.out.println(" 这是教授的信息 ");super.introduce();}
}

运行结果：

这是教授的信息
姓名：贾宝玉年龄：30 职称：高级职称基本工资30000.0 工资级别1.3

4.通过继承实现员工工资核算打印功能

父类:员工类
子类: 部门经理类、普通员工类
(1)部门经理工资=1000+单日工资*天数*等级 (1.2) 。

(2)普通员工工资=单日工资*天数*等级(1.0);

(3)员工属性:姓名，单日工资，工作天数

(4)员工方法(打印工资)
(5)普遍员工及部门经理都是员工子类，需要重写打印工资方法。
(5)定义并初始化普通员工对象，调用打印工资方法输入工资，定义并初始化部门经理对象，调用打印工资方法输入工资

难点1：细品bonus

难点2：注意类名取名规则

package com.hspedu.extend_.exercise.OOP;public class HomeWork04 {public static void main(String[] args) {manage manage = new manage("刘备", 100, 20, 1.2);manage.setBonus(3000);manage.printSal();Worker worker = new Worker("关羽", 100, 20, 1.2);worker.printSal();}
}class employee {private String name;private double salary;private int day;//分析出还有一个属性等级private double grade;public double getGrade() {return grade;}public void setGrade(double grade) {this.grade = grade;}public employee(String name, double salary, int day, double grade) {this.name = name;this.salary = salary;this.day = day;this.grade = grade;}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;}//打印工资方法public void printSal() {System.out.println(name + " 工资是= " + salary * day * grade);}
}

package com.hspedu.extend_.exercise.OOP;public class manage extends employee{public manage(String name, double salary, int day, double grade) {super(name, salary, day, grade);}//特有属性bonus为变化的，不合适初始化private double bonus = 0;public double getBonus() {return bonus;}public void setBonus(double bonus) {this.bonus = bonus;}@Overridepublic void printSal() {System.out.println("经理 " + getName() + " 工资是="+ (bonus + getDay() * getSalary() * getGrade()));}  //细品bonus
}

package com.hspedu.extend_.exercise.OOP;public class Worker extends employee{public Worker(String name, double salary, int day, double grade) {super(name, salary, day, grade);}//    @Override
//    public void printSal() {
//        super.printSal();
//    }
}

运行结果：

经理刘备工资是=5400.0
关羽工资是= 2400.0