JAVA 学习笔记(五)

   子类通过方法的重写机制可以隐藏继承父类的方法, 把父类的状态和行为改变为子类自己的状态和行为. 假如父类中有一个方法myMethod(),一旦子类重写了超类的方法myMethod() ,就隐藏了继承的方法 . 子类对象在调用方法 myMethod()时,运行结果一定是重写了方法体的实现结果. 重写方法既可以操作继承的成员变量和继承的成员方法 ,也可以操作子类新增加的成员变量和新增加的成员方法 ,但无法操作被子类隐藏的成员变量和成员方法 . 如果子类想操作被隐藏的成员变量和成员方法 ,就必须在子类的方法中调用并且使用super.  

public class Test3_18 {

  public static void main(String[] args) {
    // TODO Auto-generated method stub
    AnotherEmployee first = new AnotherEmployee("John",177,73.8d,4000,2016,10,20) ;
    System.out.println("员工信息\t姓名\t身高\t体重\t月薪\t入职时间");
    System.out.println("员工信\t"+first.getName()+"\t"+first.getHeight()+"\t"+first.getWeight()+"\t"+first.getSalary()+"\t"+first.getHireDay());
    AnotherManager mfirst =new AnotherManager("Jerry",187,80.8d,8000,2006,7,20) ; 
    mfirst.setBonus(10000) ; 
    System.out.println("经理信息\t姓名\t身高\t体重\t月薪\t入职时间\t奖金");
    System.out.println("经理信息\t"+mfirst.getName()+"\t"+mfirst.getHeight()+"\t"+mfirst.getWeight()+"\t"+mfirst.getSalary()+"\t"+mfirst.getHireDay()+"\t"+mfirst.getBonus());
    
  }

}

// 

public class AnotherPeople {
  private String name ; 
  private double height ,weight ; 
  public AnotherPeople() {
    name = "" ; 
    height = 170 ; 
    weight =70 ; 
  }
  public AnotherPeople(String name ,double height ,double weight ) {
    this.name = name ; 
    this.height = height ; 
    this.weight = weight ; 
  }
  public void setName(String name ) {
    this.name = name ; 
  }
  public void setHeight(double height) {
    this.height = height  ; 
  }
  public void setWweight(double weight) {
    this.weight = weight ; 
  }
  public String getName() {
    return this.name ; 
  }
  public double getHeight() {
    return this.height  ;
  }
  public double getWeight() {
    return this.weight ; 
  }
  
}

package cn.com.site2;
import java.util.*;
public class AnotherEmployee extends AnotherPeople{
  private double salary  ; // 子类增加的薪水 
  private Date hireDay ; // 增加了雇佣时间
  public AnotherEmployee() {
    // 无参无操作
  }
  public AnotherEmployee(String name ,double height , double weight ,double salary ,int year , int month ,int day ) {
    super(name,height,weight) ; 
    this.salary = salary ; 
    GregorianCalendar calendar = new GregorianCalendar(year ,month-1,day) ; 
    hireDay = calendar.getTime();
    
  }
  public void setSalary(double salary) {
    this.salary = salary ; 
  }
  public void setHireDay(int year ,int month ,int day ) {
    GregorianCalendar calendar = new GregorianCalendar(year ,month-1,day) ; 
    hireDay = calendar.getTime() ; 
  }
  public double getSalary() {
    return this.salary ; 
  }
  public Date getHireDay() {
    return this.hireDay ; 
  }
  public void raiseSalary(double byPercent) { // 增加了加薪的方法 
    double raise = salary*byPercent /100 ; 
    salary +=raise  ; 
  }
}

public class AnotherManager extends AnotherEmployee{
  private double bonus ;  // 增加了奖金 
  public AnotherManager() {
    
  }
  public AnotherManager(String name , double height , double weight ,double salary , int year , int month ,int day ) {
    super(name ,height ,weight,salary,year,month,day) ;   
    bonus = 0 ; 
  }
  public void setBonus(double bonus) {
    this.bonus = bonus ; 
  }
  public double getBonus() {
    double baseSalary = super.getSalary();
    return bonus+baseSalary  ; 
  }
  
}

输出 : 

员工信息  姓名  身高  体重  月薪  入职时间
员工信 John  177.0 73.8  4000.0  Thu Oct 20 00:00:00 CST 2016
经理信息  姓名  身高  体重  月薪  入职时间  奖金
经理信息  Jerry 187.0 80.8  8000.0  Thu Jul 20 00:00:00 CST 2006  18000.0