定义一个Person类，含姓名、性别、年龄、等字段；继承Person类设计Teacher类，增加职称、部门字段；继承Person类设计Student类，增加学号、入学时间、专业等字段。定义各类 的构造方法和toString方法，并分别创建对象进行测试。

首先，我们来定义一个基础的`Person`类，包含一些通用的信息：

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

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

    // toString方法展示基本信息
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", age=" + age +
                '}';
    }
}

然后，我们可以设计`Teacher`类作为`Person`的子类，添加特有的字段：

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

    // 构造方法，接收父类所有参数并初始化额外字段
    public Teacher(String name, String gender, int age, String title, String department) {
        super(name, gender, age);
        this.title = title;
        this.department = department;
    }

    // toString方法展示教师信息
    @Override
    public String toString() {
        return super.toString() +
                ", title='" + title + '\'' +
                ", department='" + department + '\'';
    }
}

接着，我们定义`Student`类作为`Person`的子类：

public class Student extends Person {
    private int studentId;
    private Date enrollmentDate;
    private String major;

    // 构造方法，接收父类所有参数并初始化额外字段
    public Student(String name, String gender, int age, int studentId, Date enrollmentDate, String major) {
        super(name, gender, age);
        this.studentId = studentId;
        this.enrollmentDate = enrollmentDate;
        this.major = major;
    }

    // toString方法展示学生信息
    @Override
    public String toString() {
        return super.toString() +
                ", studentId=" + studentId +
                ", enrollmentDate=" + enrollmentDate +
                ", major='" + major + '\'';
    }
}

现在可以创建这些类的对象并打印它们：

public static void main(String[] args) {
    Teacher teacher = new Teacher("张老师", "女", 35, "教授", "计算机系");
    System.out.println(teacher);

    Student student = new Student("小明", "男", 20, 20200101, "软件工程", "计算机科学与技术");
    System.out.println(student);
}

运行这个程序，你会看到`Teacher`和`Student`类的对象的详细信息。