利用Java的程序定义一个person类，包含姓名、性别、年龄等字段；继承person类，设计teacher类，增加：职称、部门等字段；继承person类设计Student类增加，学号、班级等字段，定义各类的构造方法和to String()方法，并分贝创建对象进行测试

好的，我懂了，下面是代码：

public class Person {
    private String name;
    private String gender;
    private int age;

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

    public String getName() {
        return name;
    }

    public String getGender() {
        return gender;
    }

    public int getAge() {
        return age;
    }

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

public class Teacher extends Person {
    private String title;
    private String department;

    public Teacher(String name, String gender, int age, String title, String department) {
        super(name, gender, age);
        this.title = title;
        this.department = department;
    }

    public String getTitle() {
        return title;
    }

    public String getDepartment() {
        return department;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "name='" + getName() + '\'' +
                ", gender='" + getGender() + '\'' +
                ", age=" + getAge() +
                ", title='" + title + '\'' +
                ", department='" + department + '\'' +
                '}';
    }
}

public class Student extends Person {
    private String studentID;
    private String className;

    public Student(String name, String gender, int age, String studentID, String className) {
        super(name, gender, age);
        this.studentID = studentID;
        this.className = className;
    }

    public String getStudentID() {
        return studentID;
    }

    public String getClassName() {
        return className;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + getName() + '\'' +
                ", gender='" + getGender() + '\'' +
                ", age=" + getAge() +
                ", studentID='" + studentID + '\'' +
                ", className='" + className + '\'' +
                '}';
    }
}

现在，我们可以通过创建对象来测试这些类：

public class Main {
    public static void main(String[] args) {
        Person person = new Person("张三", "男", 20);
        System.out.println(person.toString());

        Teacher teacher = new Teacher("李四", "女", 30, "教授", "计算机系");
        System.out.println(teacher.toString());

        Student student = new Student("王五", "男", 18, "201900001", "计算机科学与技术");
        System.out.println(student.toString());
    }
}

输出结果：

Person{name='张三', gender='男', age=20}
Teacher{name='李四', gender='女', age=30, title='教授', department='计算机系'}
Student{name='王五', gender='男', age=18, studentID='201900001', className='计算机科学与技术'}

这说明我们的代码成功地创建了这些对象，并且实现了我们的需求。