Java学习：继承

1java中子类不能调用父类的私有变量，以及其中调用的时候要用到super：

代码：

package firstcode;

import java.util.*;

public class My
{
    public static void main()
    {
        System.out.print("123");
        Manager boss = new Manager("carl",10000000,1994,1,2);
        boss.setBonus(50000);

        Employee[] staff = new Employee[1];
        staff[0] = boss;
        for(int i=0;i<staff.length;i++)
        {
            Employee e = staff[i];
            System.out.println(e.getName()+" "+e.getSalary());
        }
    }
}

class Employee
{
    public Employee(String n,double s,int year,int month,int day)
    {
        name = n;
        salary = s;
        GregorianCalendar calendar = new GregorianCalendar(year,month-1,day);
        hireDay = calendar.getTime();
    }
    public String getName()
    {
        return name;
    }
    public double getSalary()
    {
        return salary;
    }
    public Date getHireDay()
    {
        return hireDay;
    }

    public void raiseSalary(double byPercent)
    {
        double raise = salary*byPercent/100;
        salary += raise;
    }

    private String name;
    private double salary;
    private Date hireDay;
}

class Manager extends Employee
{
    public Manager(String n,double s,int year,int month,int day)
    {
        super(n,s,year,month,day);
        bonus = 0;
        //super 调用必须是子类的第一条语句。
    }
    public void setBonus(double b)
    {
        bonus = b;
    }

    public double getSalary()
    {
        double baseSalary = super.getSalary();
        return baseSalary+bonus;
        //其中这样是不可以的 : return (salary+bonus)没法工作
        //子类不能直接调用父类的私有字段。
        //也不能 return （getSalary()+bonus),
        //这里getSalary:就是无限的调用自己
    }
    private double bonus;
}