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toString()方法，并分别创建对象进行测试。

操作你已介绍的够详细的了...一步一步来就行...
这个...不会是作业吧..

import java.util.Date;
//import java.util.GregorianCalendar;

public class School{
    public static void main(String[] args){
        Person person = new Person("张三", "男", 25);
        Teacher teacher = new Teacher("张兰", "女", 24, "讲师", "英语");
        Student student = new Student("李四", "男", 23, "1001", 2011, 11, 29, "计算机");
        System.out.println(person.toString());
        System.out.println(teacher.toString());
        System.out.println(student.toString());
    }
}

class Person{
    public Person(String na, String s, int a){
        name = na;
        sex = s;
        age = a;
    }
    public String toString(){
        return "name:"+name+"  "+"sex:"+sex+"  "+"age:"+age+"";
    }
    private String name;
    private String sex;
    private int age;
}

class Teacher extends Person{
    public Teacher(String na, String s, int a, String zc, String de){
        super(na, s, a);
        zhicheng = zc;
        department = de;        
    }
    public String toString(){
        return ""+super.toString()+"  "+"zhicheng:"+zhicheng+"  "+"department:"+department+"";
    }
    private String zhicheng;
    private String department;
}

class Student extends Person{
    public Student(String na, String s, int a, String n, int year, int month, int day,  String ma){
        super(na, s, a);
        no = n;
        time = new Date(year, month, day);
        major = ma;        
    }
    public String toString(){
        return ""+super.toString()+"  "+"no:"+no+"  "+"time:"+time+"  "+"major:"+major+"";
    }
    private String no;
    private Date time;
    private String major;
}
写的仓促，仅供参考！

该Date构造方法已过时，所以改写了一下
import java.util.Date;
import java.util.GregorianCalendar;

public class School{
    public static void main(String[] args){
        Person person = new Person("张三", "男", 25);
        Teacher teacher = new Teacher("张兰", "女", 24, "讲师", "英语");
        Student student = new Student("李四", "男", 23, "1001", 2011, 11, 29, "计算机");
        System.out.println(person.toString());
        System.out.println(teacher.toString());
        System.out.println(student.toString());
    }
}

class Person{
    public Person(String na, String s, int a){
        name = na;
        sex = s;
        age = a;
    }
    public String toString(){
        return "name:"+name+"  "+"sex:"+sex+"  "+"age:"+age+"";
    }
    private String name;
    private String sex;
    private int age;
}

class Teacher extends Person{
    public Teacher(String na, String s, int a, String zc, String de){
        super(na, s, a);
        zhicheng = zc;
        department = de;        
    }
    public String toString(){
        return ""+super.toString()+"  "+"zhicheng:"+zhicheng+"  "+"department:"+department+"";
    }
    private String zhicheng;
    private String department;
}

class Student extends Person{
    public Student(String na, String s, int a, String n, int year, int month, int day,  String ma){
        super(na, s, a);
        no = n;
        GregorianCalendar calendar = new GregorianCalendar(year, month, day);
        time = calendar.getTime();
        major = ma;        
    }
    public String toString(){
        return ""+super.toString()+"  "+"no:"+no+"  "+"time:"+time+"  "+"major:"+major+"";
    }
    private String no;
    private Date time;
    private String major;
}

看着怪吓人的...

这个是基础吧      java书上里完全有    思路说的很详细   只需要定义相关的类   该继承继承就行了