《面向对象程序设计（java）》第七周学习总结(代码片段)

 1 package test1;
 2 
 3 public class Main 
 4     public static void main(String[] args) 
 5         TEST2 test2=new TEST2();
 6         test2.demo1();
 7         test2.demo3();
 8         test2.demo4();
 9         test2.tese2();
10         test2.tese3();
11         test2.tese4();
12         System.out.println(test2.e2);
13         System.out.println(test2.e3);
14         System.out.println(test2.e4);
15         System.out.println(test2.t2);
16         System.out.println(test2.t3);
17         System.out.println(test2.t4);
18     
19 

 1 package test1;
 2 
 3 public class TEST1 
 4     private String t1="这是TEST1的私有属性";
 5     public String t2="这是TEST2的公有属性";
 6     protected String t3="这是TEST1受保护的属性";
 7     String t4="这是TEST1的默认属性";
 8     private void tese1() 
 9         System.out.println("我是TEST1用private修饰符修饰的方法 ");
10     
11     public void tese2() 
12         System.out.println("我是TEST1用public修饰符修饰的方法");
13     
14     protected void tese3() 
15         System.out.println("我是TEST1用protected修饰符修饰的方法");
16     
17     void tese4() 
18         System.out.println("我是TEST1无修饰符修饰的方法");
19     
20 

 1 package test1;
 2 
 3 public class TEST2 extends TEST1 
 4     private String e1="这是TEST2的私有属性";
 5     public String e2="这是TEST2的公有属性";
 6     protected String e3="这是TEST2受保护的属性";
 7     String e4="这是TEST2的默认属性";
 8     public void demo1() 
 9         System.out.println("我是TEST2用public修饰符修饰的方法");
10     
11     private void demo2() 
12         System.out.println("我是TEST2用private修饰符修饰的方法");
13     
14     protected void demo3() 
15         System.out.println("我是TEST2用protected修饰符修饰的方法");
16     
17     void demo4() 
18         System.out.println("我是TEST2无修饰符修饰的方法");
19     
20 

 1 package equals;
 2 
 3 /**
 4  * This program demonstrates the equals method.
 5  * @version 1.12 2012-01-26
 6  * @author Cay Horstmann
 7  */
 8 public class EqualsTest
 9 
10    public static void main(String[] args)
11    
12       Employee alice1 = new Employee("Alice Adams", 75000, 1987, 12, 15);
13       Employee alice2 = alice1;
14       Employee alice3 = new Employee("Alice Adams", 75000, 1987, 12, 15);
15       Employee bob = new Employee("Bob Brandson", 50000, 1989, 10, 1);
16 
17       System.out.println("alice1 == alice2: " + (alice1 == alice2));
18 
19       System.out.println("alice1 == alice3: " + (alice1 == alice3));
20 
21       System.out.println("alice1.equals(alice3): " + alice1.equals(alice3));
22 
23       System.out.println("alice1.equals(bob): " + alice1.equals(bob));
24 
25       System.out.println("bob.toString(): " + bob);
26 
27       Manager carl = new Manager("Carl Cracker", 80000, 1987, 12, 15);
28       Manager boss = new Manager("Carl Cracker", 80000, 1987, 12, 15);
29       boss.setBonus(5000);
30       System.out.println("boss.toString(): " + boss);
31       System.out.println("carl.equals(boss): " + carl.equals(boss));
32       System.out.println("alice1.hashCode(): " + alice1.hashCode());
33       System.out.println("alice3.hashCode(): " + alice3.hashCode());
34       System.out.println("bob.hashCode(): " + bob.hashCode());
35       System.out.println("carl.hashCode(): " + carl.hashCode());
36    
37 

 1 package equals;
 2 
 3 import java.time.*;
 4 import java.util.Objects;
 5 
 6 public class Employee
 7 
 8    private String name;
 9    private double salary;
10    private LocalDate hireDay;
11 
12    public Employee(String name, double salary, int year, int month, int day)
13    
14       this.name = name;
15       this.salary = salary;
16       hireDay = LocalDate.of(year, month, day);
17    
18 
19    public String getName()
20    
21       return name;
22    
23 
24    public double getSalary()
25    
26       return salary;
27    
28 
29    public LocalDate getHireDay()
30    
31       return hireDay;
32    
33 
34    public void raiseSalary(double byPercent)
35    
36       double raise = salary * byPercent / 100;
37       salary += raise;
38    
39 
40    public boolean equals(Object otherObject)
41    
42       // 快速检查对象是否相同 
43       if (this == otherObject) return true;
44 
45       // 如果显式参数为空，则必须返回false
46       if (otherObject == null) return false;
47 
48       // 如果类不匹配，它们就不能相等
49       if (getClass() != otherObject.getClass()) return false;
50 
51       // 现在我们知道另一个对象是非空雇员
52       Employee other = (Employee) otherObject;
53 
54       // 测试字段是否具有相同的值
55       return Objects.equals(name, other.name) && salary == other.salary && Objects.equals(hireDay, other.hireDay);
56    
57 
58    public int hashCode()
59    
60       return Objects.hash(name, salary, hireDay); 
61    
62 
63    public String toString()
64    
65       return getClass().getName() + "[name=" + name + ",salary=" + salary + ",hireDay=" + hireDay
66             + "]";
67    
68 

 1 package equals;
 2 
 3 public class Manager extends Employee
 4 
 5    private double bonus;
 6 
 7    public Manager(String name, double salary, int year, int month, int day)
 8    
 9       super(name, salary, year, month, day);
10       bonus = 0;
11    
12 
13    public double getSalary()
14    
15       double baseSalary = super.getSalary();
16       return baseSalary + bonus;
17    
18 
19    public void setBonus(double bonus)
20    
21       this.bonus = bonus;
22    
23 
24    public boolean equals(Object otherObject)
25    
26       if (!super.equals(otherObject)) return false;
27       Manager other = (Manager) otherObject;
28       // super.equals检查这个和其他属于同一个类
29       return bonus == other.bonus;
30    
31    //获得散列码，看看是否相同
32    public int hashCode()
33    
34       return java.util.Objects.hash(super.hashCode(), bonus);
35    
36 
37    public String toString()
38    
39       return super.toString() + "[bonus=" + bonus + "]";
40    
41 

 1 package arrayList;
 2 
 3 import java.util.*;
 4 
 5 /**
 6  * This program demonstrates the ArrayList class.
 7  * @version 1.11 2012-01-26
 8  * @author Cay Horstmann
 9  */
10 public class ArrayListTest
11 
12    public static void main(String[] args)
13    
14       // 用三个雇员对象填充工作人员数组列表
15       ArrayList<Employee> staff = new ArrayList<>();
16 
17       staff.add(new Employee("Carl Cracker", 75000, 1987, 12, 15));
18       staff.add(new Employee("Harry Hacker", 50000, 1989, 10, 1));
19       staff.add(new Employee("Tony Tester", 40000, 1990, 3, 15));
20 
21       // 把每个人的工资提高5%
22       for (Employee e : staff)
23          e.raiseSalary(5);
24 
25       // 打印所有员工对象的信息
26       for (Employee e : staff)
27          System.out.println("name=" + e.getName() + ",salary=" + e.getSalary() + ",hireDay="
28                + e.getHireDay());
29    
30 

 1 package arrayList;
 2 
 3 import java.time.*;
 4 
 5 public class Employee
 6 
 7    private String name;
 8    private double salary;
 9    private LocalDate hireDay;
10 
11    public Employee(String name, double salary, int year, int month, int day)
12    
13       this.name = name;
14       this.salary = salary;
15       hireDay = LocalDate.of(year, month, day);
16    
17 
18    public String getName()
19    
20       return name;
21    
22 
23    public double getSalary()
24    
25       return salary;
26    
27 
28    public LocalDate getHireDay()
29    
30       return hireDay;
31    
32 
33    public void raiseSalary(double byPercent)
34    
35       double raise = salary * byPercent / 100;
36       salary += raise;
37    
38 

 1 package enums;
 2 
 3 import java.util.*;
 4 
 5 /**
 6  * This program demonstrates enumerated types.
 7  * @version 1.0 2004-05-24
 8  * @author Cay Horstmann
 9  */
10 public class EnumTest
11   
12    public static void main(String[] args)
13      
14       Scanner in = new Scanner(System.in);
15       System.out.print("Enter a size: (SMALL, MEDIUM, LARGE, EXTRA_LARGE) ");
16       String input = in.next().toUpperCase();
17       Size size = Enum.valueOf(Size.class, input);
18       System.out.println("size=" + size);
19       System.out.println("abbreviation=" + size.getAbbreviation());
20       if (size == Size.EXTRA_LARGE)
21          System.out.println("Good job--you paid attention to the _.");      
22    
23 
24 
25 enum Size
26 
      //枚举类的所有实例必须放在第一行显示。
27    SMALL("S"), MEDIUM("M"), LARGE("L"), EXTRA_LARGE("XL");
28
29    private Size(String abbreviation)  this.abbreviation = abbreviation; 
30    public String getAbbreviation()  return abbreviation; 
31 
32    private String abbreviation;
33