一个简单的Java关于类的小作业
题目：
1.定义抽象类Person，类中有属性：姓名、性别、出生日期，实例方法：计算年龄，抽象方法：play

2.定义学生类Student，继承Person，新增属性：学号；

|-定义中小学生类，继承Student，新增属性：年级、班级；方法：能够计算圆的面积

|-实现play

|-定义大学生类，继承Student，新增属性：专业、年级、班级，方法：能够计算椎体的体积

|-大学生类的学号：要求使用正则表达式验证学号是否符合规则->20开头，8位数字字符

|-实现play

3.定义员工类Employer，继承Person，新增属性：工号、月薪、部门、职位，方法：…

4.新建中小学生对象、大学生对象、员工，输出每个对象的字符串表示（属性值）、 测试各个方法。

package class_test;
import java.math.*;
public class CollegeStudent extends Student { 
@Override
	public String toString() { 
		return "bigStudent [zhuanye=" + zhuanye + ", nainji=" + nainji + ", banji=" + banji + ", getZhuanye()="
				+ getZhuanye() + ", getNainji()=" + getNainji() + ", getBanji()=" + getBanji() + ", getNumber()="
				+ getNumber() + ", getName()=" + getName() + ", getSex()=" + getSex() + ", getBirthday()="
				+ getBirthday() + ", getClass()=" + getClass() + ", hashCode()=" + hashCode() + ", toString()="
				+ super.toString() + "]";
	}
public String getZhuanye() { 
		return zhuanye;
	}
	public void setZhuanye(String zhuanye) { 
		this.zhuanye = zhuanye;
	}
	public String getNainji() { 
		return nainji;
	}
	public void setNainji(String nainji) { 
		this.nainji = nainji;
	}
	public int getBanji() { 
		return banji;
	}
	public void setBanji(int banji) { 
		this.banji = banji;
	}
private String zhuanye;
private String nainji;
private int banji;
public CollegeStudent(String zhuanye, String nainji, int i) { 
	super();
	this.zhuanye = zhuanye;
	this.nainji = nainji;
	this.banji = i;
}
public CollegeStudent() { }
int getyuanzhui(int r,int h) { 
	long area;
	area = (long) ((r*r*(Math.PI))*h*(0.3));
	return (int) area;
}
}

package class_test;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Employer extends Person { 
	@Override
	public String toString() { 
		return "Employer [gonghao=" + gonghao + ", yuexin=" + yuexin + ", bumen=" + bumen + ", zhiwei=" + zhiwei
				+ ", days=" + days + ", getGonghao()=" + getGonghao() + ", getYuexin()=" + getYuexin() + ", getBumen()="
				+ getBumen() + ", getZhiwei()=" + getZhiwei() + ", getName()=" + getName() + ", getSex()=" + getSex()
				+ ", getBirthday()=" + getBirthday() + ", getClass()=" + getClass() + ", hashCode()=" + hashCode()
				+ ", toString()=" + super.toString() + "]";
	}
	public int getGonghao() { 
		return gonghao;
	}
	public void setGonghao(int gonghao) { 
		this.gonghao = gonghao;
	}
	public int getYuexin() { 
		return yuexin;
	}
	public void setYuexin(int yuexin) { 
		this.yuexin = yuexin;
	}
	public String getBumen() { 
		return bumen;
	}
	public void setBumen(String bumen) { 
		this.bumen = bumen;
	}
	public String getZhiwei() { 
		return zhiwei;
	}
	public void setZhiwei(String zhiwei) { 
		this.zhiwei = zhiwei;
	}
	private int gonghao;
	private int yuexin;
	private String bumen;
	private String zhiwei;
	private int days;
	public Employer(String name, String sex, String birthday, int gonghao, int yuexin, String bumen, String zhiwei) { 
		this.gonghao = gonghao;
		this.yuexin = yuexin;
		this.bumen = bumen;
		this.zhiwei = zhiwei;
	}
	public Employer() { }
	
	public void getAge(String birthday1) throws ParseException { 
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd,HH:mm:ss");
		Date date = sdf.parse(birthday1);
		long time = date.getTime();
		System.out.println("出生时间距离时间原点"+time+"毫秒");
		Date date1 = new Date();
		System.out.println("当前时间为"+date1);
		long time1 = date1.getTime();
		long time2 = ((time1-time)/86400000)/365;
		System.out.println("年龄为"+time2);
}
}

package class_test;

public abstract class Person { 
@Override
	public String toString() { 
		return "Person [name=" + name + ", sex=" + sex + ", birthday=" + birthday + ", getName()=" + getName()
				+ ", getSex()=" + getSex() + ", getBirthday()=" + getBirthday() + ", getClass()=" + getClass()
				+ ", hashCode()=" + hashCode() + ", toString()=" + super.toString() + "]";
	}
public String getName() { 
		return name;
	}
	public void setName(String name) { 
		this.name = name;
	}
	public String getSex() { 
		return sex;
	}
	public void setSex(String sex) { 
		this.sex = sex;
	}
	public String getBirthday() { 
		return birthday;
	}
	public void setBirthday(String birthday) { 
		this.birthday = birthday;
	}
private String name;
private String sex;
// birthday是一个yyyy-MM-dd HH:mm:ss 类型的时间;
private String birthday;
public Person(String name, String sex, String birthday) { 
	super();
	this.name = name;
	this.sex = sex;
	this.birthday = birthday;
}
public Person() { }
void getAge() { 

}
}

package class_test;
import java.math.*;
public class Pupils extends Student { 
	@Override
	public String toString() { 
		return "littleStudent [nianji=" + nianji + ", banji=" + banji + ", getNianji()=" + getNianji() + ", getBanji()="
				+ getBanji() + ", getNumber()=" + getNumber() + ", getName()=" + getName() + ", getSex()=" + getSex()
				+ ", getBirthday()=" + getBirthday() + ", getClass()=" + getClass() + ", hashCode()=" + hashCode()
				+ ", toString()=" + super.toString() + "]";
	}
	public String getNianji() { 
		return nianji;
	}
	public void setNianji(String nianji) { 
		this.nianji = nianji;
	}
	public String getBanji() { 
		return banji;
	}
	public void setBanji(String banji) { 
		this.banji = banji;
	}
	private String nianji;
	private String banji;
	public Pupils(String name, String sex, String birthday, String number, String nianji, String banji) { 
		super(name, sex, birthday, number);
		this.nianji = nianji;
		this.banji = banji;
	}
	public Pupils() { }
	int getCircle(int r) { 
		int area;
		area = (int) (r*r*(Math.PI));
		return area;
	}

}

package class_test;

public class Student extends Person { 
	@Override
	public String toString() { 
		return "Student [number=" + number + ", getNumber()=" + getNumber() + ", toString()=" + super.toString()
				+ ", getName()=" + getName() + ", getSex()=" + getSex() + ", getBirthday()=" + getBirthday()
				+ ", getClass()=" + getClass() + ", hashCode()=" + hashCode() + "]";
	}

	public 	String getNumber() { 
		return number;
	}

	public void setNumber(String number) { 
		this.number = number;
	}

	private String number;

	public Student(String name, String sex, String birthday, String number) { 
		super(name, sex, birthday);
		this.number = number;
	}
	public Student() { }
}

package class_test;

import java.text.ParseException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class main1 { 
public static void main(String[] args) throws ParseException { 
	
	CollegeStudent bg = new CollegeStudent("网络工程","2018",1);
	Pupils ls = new Pupils("张三", "男","2000-12-12,00:00:00", "20180001", "2018", "1");
	Employer ep = new Employer("李四", "男","1970-12-12,00:00:00" , 20110001, 3000, "清洁部", "保安");

boolean a;
a = isNumLegal(ls.getNumber());
System.out.println(a);

System.out.println(bg.toString());
System.out.println(ls.toString());
System.out.println(ep.toString());
 int circle = ls.getCircle(2);
 System.out.println(circle);//算圆
 int circle1 = bg.getyuanzhui(8,4);
 System.out.println(circle1);//算圆柱
 //算年龄
 ep.getAge("1970-12-12,00:00:00");
}

private static String String(int number) { 
	// TODO Auto-generated method stub
	return null;
}
private static boolean isNumLegal(String str){ 
    String regExp = "^((20)\\d{6})$";
    Pattern p = Pattern.compile(regExp);
    Matcher m = p.matcher(str);
    return m.matches();
}
}