写抽象类Person 、Employee Person的属性：ID，gender，address 写构造方法；写普通方法：toString，写抽象方法：buyTicket（买票方法） Employee是Person的抽象子类 Employee的属性：department； 写构造方法；写普通方法：toString，写抽象方法：working 写非抽象子类 Teacher继承自Employee， Student 继承自Person Teacher的方法：toString（输出ID、gender、department） 还必须要写什么方法？ Student的属性：school，sno 方法：toString，buyTicket（输出 学生买半票） 测试：教师 myJavaTeacher 的toString 、buyTicket 和 学生xiaoMing的buyTicket

抽象类 Person：

public abstract class Person {
    protected String ID;
    protected String gender;
    protected String address;

    public Person(String ID, String gender, String address) {
        this.ID = ID;
        this.gender = gender;
        this.address = address;
    }

    public abstract void buyTicket();

    @Override
    public String toString() {
        return "ID: " + ID + ", Gender: " + gender + ", Address: " + address;
    }
}

抽象类 Employee：

public abstract class Employee extends Person {
    protected String department;

    public Employee(String ID, String gender, String address, String department) {
        super(ID, gender, address);
        this.department = department;
    }

    public abstract void working();

    @Override
    public String toString() {
        return super.toString() + ", Department: " + department;
    }
}

非抽象子类 Teacher：

public class Teacher extends Employee {
    public Teacher(String ID, String gender, String address, String department) {
        super(ID, gender, address, department);
    }

    @Override
    public void working() {
        System.out.println("Teaching");
    }

    @Override
    public void buyTicket() {
        System.out.println("Teacher buys a ticket.");
    }

    @Override
    public String toString() {
        return super.toString();
    }
}

非抽象子类 Student：

public class Student extends Person {
    private String school;
    private String sno;

    public Student(String ID, String gender, String address, String school, String sno) {
        super(ID, gender, address);
        this.school = school;
        this.sno = sno;
    }

    @Override
    public void buyTicket() {
        System.out.println("Student buys a half-price ticket.");
    }

    @Override
    public String toString() {
        return super.toString() + ", School: " + school + ", Sno: " + sno;
    }
}

测试：

public class Test {
    public static void main(String[] args) {
        Teacher myJavaTeacher = new Teacher("T1", "Male", "Beijing", "Computer Science");
        System.out.println(myJavaTeacher.toString()); // 输出 ID: T1, Gender: Male, Address: Beijing, Department: Computer Science
        myJavaTeacher.buyTicket(); // 输出 Teacher buys a ticket.

        Student xiaoMing = new Student("S1", "Male", "Shanghai", "Fudan University", "00001");
        xiaoMing.buyTicket(); // 输出 Student buys a half-price ticket.
    }
}