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、部门等字段;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toString0方法，并分别创建对象进行测试。

好的，很高兴能回答您的问题。以下是您所要求的定义Person、Teacher和Student类、各类的构造方法和toString()方法的示例代码：

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 toString() {
    return "Name: " + name + "\nGender: " + gender + "\nAge: " + age;
  }
}

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 toString() {
    return super.toString() + "\nTitle: " + title + "\nDepartment: " + department;
  }
}

class Student extends Person {
  private int id;
  private String major;
  private String enrollmentDate;

  public Student(String name, String gender, int age, int id, String major, String enrollmentDate) {
    super(name, gender, age);
    this.id = id;
    this.major = major;
    this.enrollmentDate = enrollmentDate;
  }

  public String toString() {
    return super.toString() + "\nStudent ID: " + id + "\nMajor: " + major + "\nEnrollment Date: " + enrollmentDate;
  }
}

// 创建对象并测试
Person person = new Person("张三", "男", 25);
System.out.println(person.toString());

Teacher teacher = new Teacher("李四", "女", 35, "教授", "计算机科学");
System.out.println(teacher.toString());

Student student = new Student("王五", "男", 20, 123456, "软件工程", "2021-09-01");
System.out.println(student.toString());

上述代码输出的结果如下：

Name: 张三
Gender: 男
Age: 25
Name: 李四
Gender: 女
Age: 35
Title: 教授
Department: 计算机科学
Name: 王五
Gender: 男
Age: 20
Student ID: 123456
Major: 软件工程
Enrollment Date: 2021-09-01

希望对您有所帮助！