JAVA实验题笔记 - 类的继承实验

问题描述

设计名为Person的类和它的两个子类Student和Employee。Employee有子类Faculty和Staff。

• Person有name,address,telephone,email
• Student有grade(4个年级，定义为enum)
• Employee有officer,salary,entryDate(入职日期，MyDate类型)
• 定义MyDate类，包含year,month,day
• Faculty有officeHour,rank（级别）
• Staff有jobTitle（职称）

覆盖每个类中的toString方法显示相应的类名和人名。

编写测试程序，创建Person、Student、Employee、Faculty、Staff对象，并调用他们的toString方法。

实现对Student类的clone方法，要求创建stu01学生，并将其信息拷贝给stu02；修改stu01的姓名和年级，观察stu02学生的状态。

实验对Staff类的使用初始化块实现初始化工作，要求是所有的Staff类对象的职称都初始化为newStaff。

输出形式示例（部分）

Person [name=zhangsan]
Student [name=lisi]
Employee [name=wangwu]
Faculty [name=zhaoliu]
Staff [name=Tom]

Programing Time

package cn.matce.hw7;

public class PersonSystemTest {
    public static void main(String[] args) {
        
        Person zhangsan = new Person();
        zhangsan.name = "zhangsan";
        zhangsan.toString();
        
        Student lisi = new Student();
        lisi.name = "lisi";
        lisi.toString();
        
        Employee wangwu = new Employee ();
        wangwu.name = "wangwu";
        wangwu.toString();
        
        Faculty zhaoliu = new Faculty ();
        zhaoliu.name = "zhaoliu";
        zhaoliu.toString();
        
        Staff Tom = new Staff ();
        Tom.name = "Tom";
        Tom.toString();
        
        System.out.print("\n\n");
        
        
        //第二题的主方法从此开始↓
        Student stu01 = new Student();
        Student stu02 = new Student();
        stu01.name = "Sherlock Holmes";
        stu01.grade = Student.Grade.grade1;
        
        System.out.printf("=====================================\n"
                        + "Before clone"
                      + "\n=====================================\n\n");
        
        stu01.showInfo("stu01");
        stu02.showInfo("stu02");
        
        stu02.clone(stu01); System.out.printf("\n");
        
        stu01.name = "Dr. Watson";
        stu01.grade = Student.Grade.grade2;
        
        System.out.printf("=====================================\n"
                        + "After clone & stu01 changed its info"
                      + "\n=====================================\n\n");
        
        stu01.showInfo("stu01");
        stu02.showInfo("stu02");
        
        System.out.printf("=====================================\n"
                        + "测试 jobTitle 初始化的部分"
                      + "\n=====================================\n");
        
        Staff staff01 = new Staff();
        System.out.println(staff01.jobTitle + "\n\n");

        
        System.out.printf("=====================================\n"
                        + "测试 MyDate 类的使用"
                      + "\n=====================================\n");
        Employee Wang = new Employee();
        Wang.entryDate.setMyDate(2020,4,10);
        System.out.println("Wang入职于" + Wang.entryDate.getMyDate());
    }
}

class Person {
    
    String name = "No Name";
    String address;
    String telephone;
    String email;
    
    Person () {
    }
    
    @Override
    public String toString() {
        System.out.println(getClass().getSimpleName() + " [name=" + name + "]");
        return null;
    }
}

class Student extends Person {
    enum Grade {
    grade1,grade2,grade3,grade4,gradeUnSet
    }
    Grade grade = Grade.gradeUnSet;
    
    //clone方法重写
    public void clone(Student s1) {
        name = s1.name;
        address = s1.address;
        telephone = s1.telephone;
        email = s1.email;
        grade = s1.grade;
    }
    
    public void showInfo(String sName) {
        System.out.println(sName + "----------");
        System.out.println("Name:" + name);
        System.out.println("Grade:" + grade);
        System.out.println();
    }
}

class Employee extends Person { //难点笔记↓ 花了好几h才弄懂怎么解决【捂脸】
    String officer; //职位
    double salary; //薪水
    
    MyDate entryDate; //定义MyDate类的变量entryDate，但此时指向Null
    Employee() {
        entryDate = new MyDate(); 
        //构造MyDate对象，用entryDate这个变量指向新建的对象
    }    
}

class Faculty extends Employee{
    double officeHour; //工作小时
    int rank; //级别
}

class Staff extends Employee{
    String jobTitle; //职称
    {
        jobTitle = "newStaff";
    }
}

class MyDate {
    private int year = 1970, month = 1, day = 1 ;
    MyDate() {
        
    }
    public String getMyDate() {
        return String.valueOf(year) + "年"
                + String.valueOf(month) + "月"
                + String.valueOf(day) + "日";
    }
    public void setMyDate(int y,int m,int d) {
        year = y; month = m; day = d;
    }
}

输出结果

Person [name=zhangsan]
Student [name=lisi]
Employee [name=wangwu]
Faculty [name=zhaoliu]
Staff [name=Tom]


=====================================
Before clone
=====================================

stu01----------
Name:Sherlock Holmes
Grade:grade1

stu02----------
Name:No Name
Grade:gradeUnSet


=====================================
After clone & stu01 changed its info
=====================================

stu01----------
Name:Dr. Watson
Grade:grade2

stu02----------
Name:Sherlock Holmes
Grade:grade1

=====================================
测试 jobTitle 初始化的部分
=====================================
newStaff


=====================================
测试 MyDate 类的使用
=====================================
Wang入职于2020年4月10日