第七周

 

test 1

package equals;

import java.time.*;
import java.util.Objects;

public class Employee
{
   private String name;
   private double salary;
   private LocalDate hireDay;

   public Employee(String name, double salary, int year, int month, int day)
   {
      this.name = name;
      this.salary = salary;
      hireDay = LocalDate.of(year, month, day);
   }

   public String getName()
   {
      return name;
   }

   public double getSalary()
   {
      return salary;
   }

   public LocalDate getHireDay()
   {
      return hireDay;
   }

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

   public boolean equals(Object otherObject)
   {
      // a quick test to see if the objects are identical
      if (this == otherObject) return true;

      // must return false if the explicit parameter is null
      if (otherObject == null) return false;

      // if the classes don't match, they can't be equal
      if (getClass() != otherObject.getClass()) return false;

      // now we know otherObject is a non-null Employee
      Employee other = (Employee) otherObject;

      // test whether the fields have identical values
      return Objects.equals(name, other.name) && salary == other.salary && Objects.equals(hireDay, other.hireDay);
   }

   public int hashCode()
   {
      return Objects.hash(name, salary, hireDay); 
   }

   public String toString()
   {
      return getClass().getName() + "[name=" + name + ",salary=" + salary + ",hireDay=" + hireDay
            + "]";
   }
}

Employee

package equals;

/**
 * This program demonstrates the equals method.
 * @version 1.12 2012-01-26
 * @author Cay Horstmann
 */
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));//是否引用同一个对象

      System.out.println("alice1.equals(alice3): " + alice1.equals(alice3));  //两个参数不为NULL，用a.equals(b)

      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());//地址值
      System.out.println("alice3.hashCode(): " + alice3.hashCode());
      System.out.println("bob.hashCode(): " + bob.hashCode());
      System.out.println("carl.hashCode(): " + carl.hashCode());
   }
}

main

package equals;

public class Manager extends Employee
{
   private double bonus;

   public Manager(String name, double salary, int year, int month, int day)
   {
      super(name, salary, year, month, day);
      bonus = 0;
   }

   public double getSalary()
   {
      double baseSalary = super.getSalary();
      return baseSalary + bonus;
   }

   public void setBonus(double bonus)
   {
      this.bonus = bonus;
   }

   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 java.util.Objects.hash(super.hashCode(), bonus);
   }

   public String toString()
   {
      return super.toString() + "[bonus=" + bonus + "]";
   }
}

Manager extends Employee

test 2

package arrayList;

import java.util.*;

/**
 * This program demonstrates the ArrayList class.
 * @version 1.11 2012-01-26
 * @author Cay Horstmann
 */
public class ArrayListTest
{
   public static void main(String[] args)
   {
      // fill the staff array list with three Employee objects
      ArrayList<Employee> staff = new ArrayList<>();

      staff.add(new Employee("Carl Cracker", 75000, 1987, 12, 15));
      staff.add(new Employee("Harry Hacker", 50000, 1989, 10, 1));
      staff.add(new Employee("Tony Tester", 40000, 1990, 3, 15));

      // raise everyone's salary by 5%
      for (Employee e : staff)
         e.raiseSalary(5);

      // print out information about all Employee objects
      for (Employee e : staff)
         System.out.println("name=" + e.getName() + ",salary=" + e.getSalary() + ",hireDay="
               + e.getHireDay());
   }
}

ArrayListTest

package arrayList;

import java.time.*;

public class Employee
{
   private String name;
   private double salary;
   private LocalDate hireDay;

   public Employee(String name, double salary, int year, int month, int day)
   {
      this.name = name;
      this.salary = salary;
      hireDay = LocalDate.of(year, month, day);
   }

   public String getName()
   {
      return name;
   }

   public double getSalary()
   {
      return salary;
   }

   public LocalDate getHireDay()
   {
      return hireDay;
   }

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

Employee

 test 3

import java.util.*;

public class EnumTest
{  
   public static void main(String[] args)
   {  
      Scanner in = new Scanner(System.in);
      System.out.print("Enter a size: (SMALL, MEDIUM, LARGE, EXTRA_LARGE) ");
      String input = in.next().toUpperCase();
      Size size = Enum.valueOf(Size.class, input);//将size设置成输入的()
      System.out.println("size=" + size);//printf  size
      System.out.println("abbreviation=" + size.getAbbreviation());  //输出缩写后的大小
      if (size == Size.EXTRA_LARGE)
         System.out.println("Good job--you paid attention to the _.");      //如果是xl号 输出Good job--you paid attention to the _.
   }
}

enum Size                  //枚举类
{
   SMALL("S"), MEDIUM("M"), LARGE("L"), EXTRA_LARGE("XL");

   private Size(String abbreviation) { this.abbreviation = abbreviation; }
   public String getAbbreviation() { return abbreviation; }      //缩写函数

   private String abbreviation;
}

EnumTest

 

 

public class Main {
    public static void main(String[] args) {
        TEST2 test2 = new TEST2();
        /*在下面分别调用 demo1 demo2 demo3 demo4 test1 test2 test3 test4方法
        和t1 t2 t3 t3 e1 e2 e3 e4属性，好好理解继承和权限修饰符的用法与区别*/
        System.out.println(test2.e2);
        System.out.println(test2.e3);
        System.out.println(test2.e4);
        System.out.println(test2.t2);
        System.out.println(test2.t3);
        System.out.println(test2.t4);
        test2.demo1();
        test2.demo3();
        test2.demo4();
        test2.tese2();
        test2.tese3();
        test2.tese4();
    }
}

Main

public class TEST1 {
    private String t1 = "这是TEST1的私有属性";
    public String t2 = "这是TEST1的公有属性";
    protected String t3 = "这是TEST1受保护的属性";
    String t4 = "这是TEST1的默认属性";
    private void tese1() {
        System.out.println("我是TEST1用private修饰符修饰的方法");
    }
    public void tese2() {
        System.out.println("我是TEST1用public修饰符修饰的方法");
    }
    protected void tese3() {
        System.out.println("我是TEST1用protected修饰符修饰的方法");
    }
    void tese4() {
        System.out.println("我是TEST1无修饰符修饰的方法");
    }
}

TEST1

public class TEST2 extends TEST1{
    private String e1 = "这是TEST1的私有属性";
    public String e2 = "这是TEST1的公有属性";
    protected String e3 = "这是TEST1受保护的属性";
    String e4 = "这是TEST1的默认属性";
    public void demo1() {
        System.out.println("我是TEST2用public修饰符修饰的方法");
    }
    private void demo2() {
        System.out.println("我是TEST2用private修饰符修饰的方法");
    }
    protected void demo3() {
        System.out.println("我是TEST2用protected修饰符修饰的方法");
    }
    void demo4() {
        System.out.println("我是TEST2无修饰符修饰的方法");
    }
}

TEST2 extends TEST1

 

转载于:https://www.cnblogs.com/2017xinghui/p/9736111.html