package com.wu.toString; import java.util.Date;
import java.util.GregorianCalendar; /**
*
* @author wuyong
* @email 382999338@qq.com
* @date2016年9月1日下午4:39:09
* 雇员类
*/
class Employee
{
private String name;
private double salary;//薪水
private Date hireDay;//入职时间
//构造方法：主要作用是初始化参数
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;
}
/*
* equals方法：用户检测一个对象是否等于另外一个对象。(non-Javadoc)
* 在Object类中，这个方法将判断两个对象是否具有相同的引用。
* @see java.lang.Object#equals(java.lang.Object)
*/ public boolean equals(Object otherObject)
{
// a quick test to see if the objects are identical
//如果Employee与参数otherObjectd的引用的对象相同，返回true
if (this == otherObject) return true; // must return false if the explicit parameter is null
//如果参数为空返回的是false
if (otherObject == null) return false; // if the classes don't match, they can't be equal
//如果Employee与otherObject类型不同，返回false
if (getClass() != otherObject.getClass())
return false; // now we know otherObject is a non-null Employee
//将otherObject强制转换为Employee类型
Employee other = (Employee) otherObject; // test whether the fields have identical values
return name.equals(other.name)//可以写成this.name.equals(other.name)
&& salary == other.salary
&& hireDay.equals(other.hireDay);
}
/*
* ashCode方法：散列码是由对象导出的一个整型值。没有规律(non-Javadoc)
* @see java.lang.Object#hashCode()
*/
public int hashCode()
{
return 7 * name.hashCode()
+ 11 * new Double(salary).hashCode()
+ 13 * hireDay.hashCode();
}
/*
* toString方法：用于返回表示对象值得字符串(non-Javadoc)
* @see java.lang.Object#toString()
*/
public String toString()
{
return getClass().getName()
+ "[name=" + name
+ ",salary=" + salary
+ ",hireDay=" + hireDay
+ "]";
}
}
package com.wu.toString; /**
* 经理类，继承雇员类
* @author wuyong
* @email 382999338@qq.com
* @date2016年9月1日下午4:37:51
*/ class Manager extends Employee
{
private double bonus;//奖金 public Manager(String n, double s, int year, int month, int day)
{
super(n, s, year, month, day);
bonus = 0;
}
//计算薪水
public double getSalary()
{
double baseSalary = super.getSalary();//调用父类的方法
return baseSalary + bonus;
} public void setBonus(double b)
{
bonus = b;
} public boolean equals(Object otherObject)
{
if (!super.equals(otherObject)) return false;
Manager other = (Manager) otherObject;
// super.equals checked that this and other belong to the same class
return bonus == other.bonus;
} public int hashCode()
{
return super.hashCode()
+ 17 * new Double(bonus).hashCode();
} public String toString()
{
return super.toString()
+ "[bonus=" + bonus
+ "]";
} }
package com.wu.toString;
/**
*
* @author wuyong
* @email 382999338@qq.com
* @date2016年9月1日下午4:33:20
* 测试类
*
*/
import java.util.*; public class EqualsTest
{
public static void main(String[] args)
{
Employee alice1 = new Employee("Alice Adams", 75000, 1987, 12, 15);
Employee alice2 = alice1;
Employee alice3 = new Employee("Alice Adams", 75000, 1987, 12, 15);
Employee bob = new Employee("Bob Brandson", 50000, 1989, 10, 1); System.out.println("alice1 == alice2: " + (alice1 == alice2)); System.out.println("alice1 == alice3: " + (alice1 == alice3)); System.out.println("alice1.equals(alice3): " + alice1.equals(alice3)); System.out.println("alice1.equals(bob): " + alice1.equals(bob)); System.out.println("bob.toString(): " + bob); Manager carl = new Manager("Carl Cracker", 80000, 1987, 12, 15);
Manager boss = new Manager("Carl Cracker", 80000, 1987, 12, 15);
boss.setBonus(5000);
System.out.println("boss.toString(): " + boss);
System.out.println("carl.equals(boss): " + carl.equals(boss));
System.out.println("alice1.hashCode(): " + alice1.hashCode());
System.out.println("alice3.hashCode(): " + alice3.hashCode());
System.out.println("bob.hashCode(): " + bob.hashCode());
System.out.println("carl.hashCode(): " + carl.hashCode());
}
}