狄慧201771010104《面向对象程序设计（java）》第八周学习总结

Posted 2021-01-14 dhlll

实验六接口的定义与使用

实验时间 2018-10-18

一、实验目的与要求

(1) 掌握接口定义方法；

(2) 掌握实现接口类的定义要求；

(3) 掌握实现了接口类的使用要求；

(4) 掌握程序回调设计模式；

(5) 掌握Comparator接口用法；

(6) 掌握对象浅层拷贝与深层拷贝方法；

(7) 掌握Lambda表达式语法；

(8) 了解内部类的用途及语法要求。

二、实验内容和步骤

实验1： 导入第6章示例程序，测试程序并进行代码注释。

测试程序1：

l  编辑、编译、调试运行阅读教材214页-215页程序6-1、6-2，理解程序并分析程序运行结果；

l  在程序中相关代码处添加新知识的注释。

l  掌握接口的实现用法；

l  掌握内置接口Compareable的用法。

package interfaces;

import java.util.*;

/**
 * This program demonstrates the use of the Comparable interface.
 * @version 1.30 2004-02-27
 * @author Cay Horstmann
 */
public class EmployeeSortTest
{
   public static void main(String[] args)
   {
      Employee[] staff = new Employee[3];//普通数组

      staff[0] = new Employee("Harry Hacker", 35000);
      staff[1] = new Employee("Carl Cracker", 75000);
      staff[2] = new Employee("Tony Tester", 38000);

      Arrays.sort(staff);//静态方法sort

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

package interfaces;

public class Employee implements Comparable<Employee>//Employee实现JDK内置接口Comparable
{
   private String name;
   private double salary;
   //构造方法
   public Employee(String name, double salary)
   {
      this.name = name;
      this.salary = salary;
   }
   //访问器
   public String getName()
   {
      return name;
   }

   public double getSalary()
   {
      return salary;
   }
   //调用方法
   public void raiseSalary(double byPercent)
   {
      double raise = salary * byPercent / 100;
      salary += raise;
   }

   /**
    * Compares employees by salary
    * @param other another Employee object
    * @return a negative value if this employee has a lower salary than
    * otherObject, 0 if the salaries are the same, a positive value otherwise
    */
   public int compareTo(Employee other)
   {
      return Double.compare(salary, other.salary);//静态Double.compare方法
   }
}

测试程序2：

l  编辑、编译、调试以下程序，结合程序运行结果理解程序；

interface  A {   double g=9.8;   void show( ); } class C implements A {   public void show( )   {System.out.println("g="+g);} }   class InterfaceTest {   public static void main(String[ ] args)   {        A a=new C( );        a.show( );        System.out.println("g="+C.g);   } }

public interface  A
    {
      double g=9.8;
      void show( );
    }

class C implements A
{
  public void show( )
  {System.out.println("g="+g);}
 
}

package InterfaceTest;
public class InterfaceTest {
     public static void main(String[ ] args)
      {
           A a=new C( );
           a.show( );
           System.out.println("g="+C.g);
      }
    }

测试程序3：

l  在elipse IDE中调试运行教材223页6-3，结合程序运行结果理解程序；

l  26行、36行代码参阅224页，详细内容涉及教材12章。

l  在程序中相关代码处添加新知识的注释。

l  掌握回调程序设计模式；

package timer;

/**
   @version 1.01 2015-05-12
   @author Cay Horstmann
*/

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.Timer; 
// to resolve conflict with java.util.Timer

public class TimerTest
{  
   public static void main(String[] args)
   {  
      ActionListener listener = new TimePrinter();
       //实现了ActionListener的类对象
      // construct a timer that calls the listener
      // once every 10 seconds
      Timer t = new Timer(10000, listener);//定义间隔
      t.start();

      JOptionPane.showMessageDialog(null, "Quit program?");
      System.exit(0);
   }
}

class TimePrinter implements ActionListener//内置接口
{  
   public void actionPerformed(ActionEvent event)
   {  
      System.out.println("At the tone, the time is " + new Date());
      Toolkit.getDefaultToolkit().beep();
   }
}

测试程序4：

l  调试运行教材229页-231页程序6-4、6-5，结合程序运行结果理解程序；

l  在程序中相关代码处添加新知识的注释。

l  掌握对象克隆实现技术；

l  掌握浅拷贝和深拷贝的差别。

package clone;

/**
 * This program demonstrates cloning.
 * @version 1.10 2002-07-01
 * @author Cay Horstmann
 */
public class CloneTest
{
   public static void main(String[] args)
   {
      try
      {
        
         Employee original = new Employee("John Q. Public", 50000);
         //Employee是一个自定义类
         original.setHireDay(2000, 1, 1);
         Employee copy = original.clone();
         copy.raiseSalary(10);//原有对象不会发生变化
         copy.setHireDay(2002, 12, 31);//更改器
         System.out.println("original=" + original);//字符串连接
         System.out.println("copy=" + copy);
      }
      catch (CloneNotSupportedException e)
      {
         e.printStackTrace();
      }
   }
}

实验2： 导入第6章示例程序6-6，学习Lambda表达式用法。

l  调试运行教材233页-234页程序6-6，结合程序运行结果理解程序；

l  在程序中相关代码处添加新知识的注释。

l  将27-29行代码与教材223页程序对比，将27-29行代码与此程序对比，体会Lambda表达式的优点。

package lambda;

import java.util.*;

import javax.swing.*;
import javax.swing.Timer;

/**
 * This program demonstrates the use of lambda expressions.
 * @version 1.0 2015-05-12
 * @author Cay Horstmann
 */
public class LambdaTest
{
   public static void main(String[] args)
   {
      String[] planets = new String[] { "Mercury", "Venus", "Earth", "Mars", 
            "Jupiter", "Saturn", "Uranus", "Neptune" };//定义数组planets
      System.out.println(Arrays.toString(planets));//静态方法
      System.out.println("Sorted in dictionary order:");
      Arrays.sort(planets);//Arrays.sort方法接收实验Lambda类的对象
      System.out.println(Arrays.toString(planets));
      System.out.println("Sorted by length:");
      Arrays.sort(planets, (first, second) -> first.length() - second.length());//Lambda表达式
      System.out.println(Arrays.toString(planets));
            
      Timer t = new Timer(1000, event ->
         System.out.println("The time is " + new Date()));//Lambda表达式
      t.start();   
         
      // keep program running until user selects "Ok"
      JOptionPane.showMessageDialog(null, "Quit program?");
      System.exit(0);   //返回类型      
   }
}

package clone;

import java.util.Date;
import java.util.GregorianCalendar;

public class Employee implements Cloneable
{
//定义三个私有属性
   private String name;//string类在lang包
   private double salary;
   private Date hireDay;

   public Employee(String name, double salary)
   {
      this.name = name;
      this.salary = salary;
      hireDay = new Date();
   }//构造方法

   public Employee clone() throws CloneNotSupportedException
   {
      // call Object.clone()
      Employee cloned = (Employee) super.clone();//强制类型转换

      // clone mutable fields
      cloned.hireDay = (Date) hireDay.clone();

      return cloned;
   }

   /**
    * Set the hire day to a given date. 
    * @param year the year of the hire day
    * @param month the month of the hire day
    * @param day the day of the hire day
    */
   public void setHireDay(int year, int month, int day)
   {
      Date newHireDay = new GregorianCalendar(year, month - 1, day).getTime();
       //创建一个实例字段变异的实例
      // Example of instance field mutation
      hireDay.setTime(newHireDay.getTime());
   }

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

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

 

注：以下实验课后完成

实验3: 编程练习

l  编制一个程序，将身份证号.txt 中的信息读入到内存中；

l  按姓名字典序输出人员信息；

l  查询最大年龄的人员信息；

l  查询最小年龄人员信息；

l  输入你的年龄，查询身份证号.txt中年龄与你最近人的姓名、身份证号、年龄、性别和出生地；

l  查询人员中是否有你的同乡。

import java.io.BufferedReader;
        import java.io.File;
        import java.io.FileInputStream;
        import java.io.FileNotFoundException;
        import java.io.IOException;
        import java.io.InputStreamReader;
        import java.util.ArrayList;
        import java.util.Arrays;
        import java.util.Collections;
        import java.util.Scanner;


public class Search{

      private static ArrayList<Person> Personlist1;
       public static void main(String[] args) {
         
          Personlist1 = new ArrayList<>();
         
          Scanner scanner = new Scanner(System.in);
          File file = new File("E:\\面向对象程序设计Java\\实验\\实验六\\身份证号.txt");
   
                try {
                     FileInputStream F = new FileInputStream(file);
                     BufferedReader in = new BufferedReader(new InputStreamReader(F));
                     String temp = null;
                     while ((temp = in.readLine()) != null) {
                        
                        Scanner linescanner = new Scanner(temp);
                        
                        linescanner.useDelimiter(" ");    
                        String name = linescanner.next();
                        String id = linescanner.next();
                        String sex = linescanner.next();
                        String age = linescanner.next();
                        String place =linescanner.nextLine();
                        Person Person = new Person();
                        Person.setname(name);
                        Person.setid(id);
                        Person.setsex(sex);
                        int a = Integer.parseInt(age);
                        Person.setage(a);
                        Person.setbirthplace(place);
                        Personlist1.add(Person);

                    }
                } catch (FileNotFoundException e) {
                    System.out.println("查找不到信息");
                    e.printStackTrace();
                } catch (IOException e) {
                    System.out.println("信息读取有误");
                    e.printStackTrace();
                }
                boolean isTrue = true;
                while (isTrue) {
                    System.out.println("******************************************");
                    System.out.println("1:按姓名字典顺序输出信息；");
                    System.out.println("2:查询最大年龄与最小年龄人员信息；");
                    System.out.println("3：按省份找你的同乡；");
                    System.out.println("4:输入你的年龄,查询年龄与你最近人的信息；");
                    System.out.println("5：退出");
                    System.out.println("******************************************");
                    int type = scanner.nextInt();
                    switch (type) {
                    case 1:
                        Collections.sort(Personlist1);
                        System.out.println(Personlist1.toString());
                        break;
                    case 2:
                        
                        int max=0,min=100;int j,k1 = 0,k2=0;
                        for(int i=1;i<Personlist1.size();i++)
                        {
                            j=Personlist1.get(i).getage();
                           if(j>max)
                           {
                               max=j; 
                               k1=i;
                           }
                           if(j<min)
                           {
                               min=j; 
                               k2=i;
                           }

                        }  
                        System.out.println("年龄最大："+Personlist1.get(k1));
                        System.out.println("年龄最小："+Personlist1.get(k2));
                        break;
                    case 3:
                        System.out.println("place?");
                        String find = scanner.next();        
                        String place=find.substring(0,3);
                        String place2=find.substring(0,3);
                        for (int i = 0; i <Personlist1.size(); i++) 
                        {
                            if(Personlist1.get(i).getbirthplace().substring(1,4).equals(place)) 
                            {
                                System.out.println("你的同乡："+Personlist1.get(i));
                            }
                        } 

                        break;
                    case 4:
                        System.out.println("年龄：");
                        int yourage = scanner.nextInt();
                        int close=ageclose(yourage);
                        int d_value=yourage-Personlist1.get(close).getage();
                        System.out.println(""+Personlist1.get(close));
                  
                        break;
                    case 5:
                   isTrue = false;
                   System.out.println("再见!");
                        break;
                    default:
                        System.out.println("输入有误");
                    }
                }
            }
            public static int ageclose(int age) {
                   int m=0;
                int    max=53;
                int d_value=0;
                int k=0;
                for (int i = 0; i < Personlist1.size(); i++)
                {
                    d_value=Personlist1.get(i).getage()-age;
                    if(d_value<0) d_value=-d_value; 
                    if (d_value<max) 
                    {
                       max=d_value;
                       k=i;
                    }

                 }    return k;
                
             }

   

 }

public class Person implements Comparable<Person> {
            private String name;
            private String id;
            private int age;
            private String sex;
            private String birthplace;

    public String getname() {
        return name;
        }
    public void setname(String name) {
        this.name = name;
    }
    public String getid() {
        return id;
    }
    public void setid(String id) {
        this.id= id;
    }
    public int getage() {
    
        return age;
    }
    public void setage(int age) {
        // int a = Integer.parseInt(age);
        this.age= age;
    }
    public String getsex() {
        return sex;
    }
    public void setsex(String sex) {
        this.sex= sex;
    }
    public String getbirthplace() {
        return birthplace;
    }
    public void setbirthplace(String birthplace) {
        this.birthplace= birthplace;
}

    public int compareTo(Person o) {
        return this.name.compareTo(o.getname());

}

    public String toString() {
        return  name+"	"+sex+"	"+age+"	"+id+"	";

}



}

实验4：内部类语法验证实验

实验程序1：

l  编辑、调试运行教材246页-247页程序6-7，结合程序运行结果理解程序；

l  了解内部类的基本用法。

package innerClass;

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.Timer;

/**
 * This program demonstrates the use of inner classes.
 * @version 1.11 2015-05-12
 * @author Cay Horstmann
 */
public class InnerClassTest
{
   public static void main(String[] args)
   {
      TalkingClock clock = new TalkingClock(1000, true);//实现了TalkingClock的类对象
      clock.start();

      // keep program running until user selects "Ok"
      JOptionPane.showMessageDialog(null, "Quit program?");
      System.exit(0);//
   }
}

/**
 * A clock that prints the time in regular intervals.
 */
class TalkingClock
{
   //声明属性
    private int interval;
   private boolean beep;

   /**
    * Constructs a talking clock
    * @param interval the interval between messages (in milliseconds)
    * @param beep true if the clock should beep
    */
   public TalkingClock(int interval, boolean beep)
   {
      this.interval = interval;
      this.beep = beep;
   }//构造方法

   /**
    * Starts the clock.
    */
   public void start()
   {
      ActionListener listener = new TimePrinter();
      Timer t = new Timer(interval, listener);
      t.start();
   }

   public class TimePrinter implements ActionListener//实现ActionListener的公共类TimePrinter
   {
      public void actionPerformed(ActionEvent event)
      {
         System.out.println("At the tone, the time is " + new Date());
         if (beep) Toolkit.getDefaultToolkit().beep();
      }
   }
}

实验程序2：

l  编辑、调试运行教材254页程序6-8，结合程序运行结果理解程序；

l  了解匿名内部类的用法。

package anonymousInnerClass;

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.Timer;

/**
 * This program demonstrates anonymous inner classes.
 * @version 1.11 2015-05-12
 * @author Cay Horstmann
 */
public class AnonymousInnerClassTest
{
   public static void main(String[] args)
   {
      TalkingClock clock = new TalkingClock();//TalkingClock类声明为私有的
      clock.start(1000, true);

      // keep program running until user selects "Ok"
      JOptionPane.showMessageDialog(null, "Quit program?");
      System.exit(0);
   }
}

/**
 * A clock that prints the time in regular intervals.
 */
class TalkingClock
{
   /**
    * Starts the clock.
    * @param interval the interval between messages (in milliseconds)
    * @param beep true if the clock should beep
    */
   public void start(int interval, boolean beep)
   {
      ActionListener listener = new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               System.out.println("At the tone, the time is " + new Date());
               if (beep) Toolkit.getDefaultToolkit().beep();
               //外围类引用.
            }
         };
      Timer t = new Timer(interval, listener);
      t.start();
   }
}

实验程序3：

l  在elipse IDE中调试运行教材257页-258页程序6-9，结合程序运行结果理解程序；

l  了解静态内部类的用法。

package staticInnerClass;

/**
 * This program demonstrates the use of static inner classes.
 * @version 1.02 2015-05-12
 * @author Cay Horstmann
 */
public class StaticInnerClassTest
{
   public static void main(String[] args)
   {
      double[] d = new double[20];
      for (int i = 0; i < d.length; i++)
         d[i] = 100 * Math.random();//算法
      ArrayAlg.Pair p = ArrayAlg.minmax(d);
      System.out.println("min = " + p.getFirst());
      System.out.println("max = " + p.getSecond());
   }//访问器
}

class ArrayAlg
{
   /**
    * A pair of floating-point numbers
    */
   public static class Pair
   {
      //声明私有属性       
      private double first;
      private double second;

      /**
       * Constructs a pair from two floating-point numbers
       * @param f the first number
       * @param s the second number
       */
      public Pair(double f, double s)
      {
         first = f;
         second = s;
      }

      /**
       * Returns the first number of the pair
       * @return the first number
       */
      public double getFirst()
      {
         return first;
      }
     // 访问器
      /**
       * Returns the second number of the pair
       * @return the second number
       */
      public double getSecond()
      {
         return second;
      }
   }

   /**
    * Computes both the minimum and the maximum of an array
    * @param values an array of floating-point numbers
    * @return a pair whose first element is the minimum and whose second element
    * is the maximum
    */
   public static Pair minmax(double[] values)
   {
      double min = Double.POSITIVE_INFINITY;
      double max = Double.NEGATIVE_INFINITY;//变量
      for (double v : values)
      {
         if (min > v) min = v;
         if (max < v) max = v;
      }
      return new Pair(min, max);
   }
}

三、实验总结：

       在这次实验中，我了解并学习了接口的实现用法、内置接口Compareable的用法、对象克隆实现技术以及Lambda表达式。通过自学，我接触了内部类、匿名内部类以及静态内部类的用法。在编程和编译过程中遇到的一些难题和出现的一些问题，我通过查阅资料、上网查找和同学讨论得以解决。