201871010112-梁丽珍《面向对象程序设计（java）》第八周学习总结

项目	内容
这个作业属于哪个课程	https://www.cnblogs.com/nwnu-daizh/
这个作业的要求在哪里	https://www.cnblogs.com/nwnu-daizh/p/11703678.html
作业学习目标	掌握接口定义方法； 掌握实现接口类的定义要求； 掌握实现了接口类的使用要求； 理解程序回调设计模式； 掌握Comparator接口用法； 掌握对象浅层拷贝与深层拷贝方法； 掌握Lambda表达式语法； 了解内部类的用途及语法要求。

第一部分：总结第六章理论知识

第二部分：实验部分

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：

　　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；

　　在程序中相关代码处添加新知识的注释。

　　掌握接口的实现用法；

　　掌握内置接口Compareable的用法。

6-1源代码：

package interfaces;

//使用 implements 关键字实现泛型  Comparable<Employee>接口
public class Employee implements Comparable<Employee>
{
   private String name;
   private double salary;

   public Employee(String name, double salary)
   {
      this.name = name;
      this.salary = salary;
   }

   public String getName()
   {
      return name;
   }

   public double getSalary()
   {
      return salary;
   }

   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)	//compareTo方法
   {
      return Double.compare(salary, other.salary);	//通过salary进行排序
   }//（使用静态Double.compare方法，如果第一个参数小于第二个参数，它会返回一个负值；如果二者相等则返回0；否则返回一个正值。）
}

6-2源代码：

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)
   {
      var staff = new Employee[3];

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

      Arrays.sort(staff);	//使用Arrays类中sort方法对对象数组进行排序

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

运行结果：

修改为通过姓名进行排序输出：

测试程序2：

　　编辑、编译、调试以下程序，结合程序运行结果理解程序；

代码：

package InterfaceTest;

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);
	}

}

运行结果：

测试程序3：

　　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；

　　26行、36行代码参阅224页，详细内容涉及教材12章。

　　在程序中相关代码处添加新知识的注释。

　　 掌握回调程序设计模式；

源代码：

package timer;

/**
   @version 1.02 2017-12-14
   @author Cay Horstmann
*/

import java.awt.*;
import java.awt.event.*;
import java.time.*;
import javax.swing.*;

public class TimerTest
{
   public static void main(String[] args)
   {
      var listener = new TimePrinter();		//创建类对象

      // construct a timer that calls the listener	（构造一个调用侦听器的计时器）
      // once every second
      Timer t = new Timer(1000, listener);		//Timer构造器，第一个参数是发出通告的时间间隔（10秒），第二个参数是监听器对象
      t.start();								//启动定时器

      // keep program running until the user selects "OK"	（保持程序运行直到用户选择“OK”）
      JOptionPane.showMessageDialog(null, "Quit program?");
      System.exit(0);
   }
}
//定义一个实现ActionListener接口的类
class TimePrinter implements ActionListener
{
   public void actionPerformed(ActionEvent event)		//调用actionPerformed方法，ActionEvent参数提供了事件的相关信息
   {
      System.out.println("At the tone, the time is "
         + Instant.ofEpochMilli(event.getWhen()));
      Toolkit.getDefaultToolkit().beep();			//获得默认的工具箱；发出一声铃响
   }
}

运行结果：

测试程序4：

　　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；

　　在程序中相关代码处添加新知识的注释。

　　掌握对象克隆实现技术；

　　掌握浅拷贝和深拷贝的差别。

6-4 CloneTest.java 源代码：

package clone;

/**
 * This program demonstrates cloning.
 * @version 1.11 2018-03-16
 * @author Cay Horstmann
 */
public class CloneTest
{
   public static void main(String[] args) throws CloneNotSupportedException
   {
	  Employee original = new Employee("John Q. Public", 50000);
      original.setHireDay(2000, 1, 1);
      Employee copy = original.clone();	//使用clone方法，copy是一个新对象，它的初始状态与original相同，但它们各有各自不同的状态
      copy.raiseSalary(10);
      copy.setHireDay(2002, 12, 31);
      System.out.println("original=" + original);
      System.out.println("copy=" + copy);
   }
}

6-5源代码：

package clone;

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

//使用implements关键字实现Cloneable接口
public class Employee implements Cloneable
{
   private String name;
   private double salary;
   private Date hireDay;

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

   //Employee和Date类实现cloneable接口
   //Object类的clone方法抛出一个CloneNotSupportedException 异常
   //声明这个异常
   public Employee clone() throws CloneNotSupportedException
   {
      // call Object.clone()	（调用Object.clone()）
      Employee cloned = (Employee) super.clone();	//super.clone()克隆可变字段

      // clone mutable fields
      cloned.hireDay = (Date) hireDay.clone();		//克隆可变字段

      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();

      // example of instance field mutation	（实例字段变异示例）
      hireDay.setTime(newHireDay.getTime());
   }

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

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

运行结果：

实验2： 导入第6章示例程序6-6，学习Lambda表达式用法。

　　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；

　　在程序中相关代码处添加新知识的注释。

　　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。

6-6源代码：

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)
   {
      var planets = new String[] { "Mercury", "Venus", "Earth", "Mars",
         "Jupiter", "Saturn", "Uranus", "Neptune" };		//数组
      System.out.println(Arrays.toString(planets));
      System.out.println("Sorted in dictionary order:");
      Arrays.sort(planets);			//Arrays.sort方法，对数组排序
      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));

      var timer = new Timer(1000, event ->				//Timer构造器
         System.out.println("The time is " + new Date()));
      timer.start();   

      // keep program running until user selects "OK"	（保持程序运行直到用户选择“OK”）
      JOptionPane.showMessageDialog(null, "Quit program?");
      System.exit(0);
   }
}

运行结果：

实验3: 编程练习

　　编制一个程序，将身份证号.txt 中的信息读入到内存中；

　　按姓名字典序输出人员信息；

　　查询最大年龄的人员信息；

　　查询最小年龄人员信息；

　　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；

　　查询人员中是否有你的同乡。

代码：

package ID;
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.Scanner;
import java.util.Collections;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class Test extends JFrame {
    private static ArrayList<Citizen> citizenlist;
    private static ArrayList<Citizen> list;
    private JPanel panel;
    private JPanel buttonPanel;
    private static final int DEFAULT_WITH = 600;
    private static final int DEFAULT_HEIGHT = 300;

    public Test(){
        citizenlist = new ArrayList<>();
        Scanner scanner = new Scanner(System.in);
        File file = new File("F://身份证号.txt");
        try {
            FileInputStream fis = new FileInputStream(file);
            BufferedReader in = new BufferedReader(new InputStreamReader(fis));
            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 birthplace = linescanner.nextLine();
                Citizen citizen = new Citizen();
                citizen.setName(name);
                citizen.setId(id);
                citizen.setSex(sex);
                int ag = Integer.parseInt(age);
                citizen.setage(ag);
                citizen.setBirthplace(birthplace);
                citizenlist.add(citizen);

            }
        } catch (FileNotFoundException e) {
            System.out.println("信息文件找不到");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("信息文件读取错误");
            e.printStackTrace();
        }
        panel = new JPanel();
        panel.setLayout(new BorderLayout());
        JTextArea jt = new JTextArea();
        panel.add(jt);
        add(panel, BorderLayout.NORTH);
        buttonPanel = new JPanel();
        buttonPanel.setLayout(new GridLayout(1, 7));
        JButton jButton = new JButton("按姓名字典序输出人员信息");
        JButton jButton1 = new JButton("查询年龄最大和年龄最小的人员");
        JLabel lab = new JLabel("查询是否有你的老乡");
        JTextField jt1 = new JTextField();
        JLabel lab1 = new JLabel("查找年龄与你相近的人：");
        JTextField jt2 = new JTextField();
        JLabel lab2 = new JLabel("输入你的身份证号码：");
        JTextField jt3 = new JTextField();
        JButton jButton2 = new JButton("退出");
        jButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Collections.sort(citizenlist);
                jt.setText(citizenlist.toString());
            }
        });
        jButton1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                int max = 0, min = 100;
                int j, k1 = 0, k2 = 0;
                for (int i = 1; i < citizenlist.size(); i++) {
                    j = citizenlist.get(i).getage();
                    if (j > max) {
                        max = j;
                        k1 = i;
                    }
                    if (j < min) {
                        min = j;
                        k2 = i;
                    }

                }
                jt.setText("年龄最大：" + citizenlist.get(k1) + "年龄最小：" + citizenlist.get(k2));
            }
        });
        jButton2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                dispose();
                System.exit(0);
            }
        });
        jt1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String find = jt1.getText();
                String text="";
                String place = find.substring(0, 3);
                for (int i = 0; i < citizenlist.size(); i++) {
                    if (citizenlist.get(i).getBirthplace().substring(1, 4).equals(place)) {
                        text+="\n"+citizenlist.get(i);
                        jt.setText("老乡：" + text);
                    }
                }
            }
        });
        jt2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String yourage = jt2.getText();
                int a = Integer.parseInt(yourage);
                int near = agenear(a);
                int value = a - citizenlist.get(near).getage();
                jt.setText("年龄相近：" + citizenlist.get(near));
            }
        });
        jt3.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                list = new ArrayList<>();
                Collections.sort(citizenlist);
                String key = jt3.getText();
                for (int i = 1; i < citizenlist.size(); i++) {
                    if (citizenlist.get(i).getId().contains(key)) {
                        list.add(citizenlist.get(i));
                        jt.setText("emmm！你可能是：\n" + list);
                    }
                }
            }
        });
        buttonPanel.add(jButton);
        buttonPanel.add(jButton1);
        buttonPanel.add(lab);
        buttonPanel.add(jt1);
        buttonPanel.add(lab1);
        buttonPanel.add(jt2);
        buttonPanel.add(lab2);
        buttonPanel.add(jt3);
        buttonPanel.add(jButton2);
        add(buttonPanel, BorderLayout.SOUTH);
        setSize(DEFAULT_WITH, DEFAULT_HEIGHT);
    }

    public static int agenear(int age) {
        int min = 53, value = 0, k = 0;
        for (int i = 0; i < citizenlist.size(); i++) {
            value = citizenlist.get(i).getage() - age;
            if (value < 0)
                value = -value;
            if (value < min) {
                min = value;
                k = i;
            }
        }
        return k;
    }

}

package ID;
public class Citizen implements Comparable<Citizen> {

    private String name;
    private String id;
    private String sex;
    private int age;
    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 String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getage() {
        return age;
    }

    public void setage(int age) {
        this.age = age;
    }

    public String getBirthplace() {
        return birthplace;
    }

    public void setBirthplace(String birthplace) {
        this.birthplace = birthplace;
    }

    public int compareTo(Citizen other) {
        return this.name.compareTo(other.getName());
    }

    public String toString() {
        return name + "\t" + sex + "\t" + age + "\t" + id + "\t" + birthplace + "\n";
    }
}

package ID;
import java.awt.*;
import javax.swing.*;

public class ButtonTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(() -> {
            JFrame frame = new Test();
            frame.setTitle("身份证");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setVisible(true);
        });
    }
}

结果：

实验4：内部类语法验证实验

实验程序1：

　　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；

　　了解内部类的基本用法。

6-7源代码：

package innerClass;

import java.awt.*;
import java.awt.event.*;
import java.time.*;

import javax.swing.*;

/**
 * This program demonstrates the use of inner classes.
 * @version 1.11 2017-12-14
 * @author Cay Horstmann
 */
public class InnerClassTest
{
   public static void main(String[] args)
   {
      var clock = new TalkingClock(1000, true);
      clock.start();

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

/**
 * A clock that prints the time in regular intervals.
 */
class TalkingClock
{
   private int interval;		//参数：发布通告的间隔
   private boolean beep;		//参数：开关铃声的标志

   /**
    * 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;		//this引用
   }

   /**
    * Starts the clock.
    */
   public void start()		//start方法
   {
      var listener = new TimePrinter();		//创建TimePrinter对象
      var timer = new Timer(interval, listener);
      timer.start();
   }
//TimePrinter类位于 TalkingClock类内部（内部类访问对象状态：TimePrinter对象由TalkingClock类方法构造）
 //定义一个实现ActionListener接口的类
   public class TimePrinter implements ActionListener
   {
      public void actionPerformed(ActionEvent event)	//调用actionPerformed方法，并在发出铃声之前检查了beep标志
      {
         System.out.println("At the tone, the time is "
            + Instant.ofEpochMilli(event.getWhen()));
         if (beep) Toolkit.getDefaultToolkit().beep();
      }
   }
}

运行结果：

实验程序2：

　　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；

　　掌握匿名内部类的用法。

6-8源代码：

package anonymousInnerClass;

import java.awt.*;
import java.awt.event.*;
import java.time.*;

import javax.swing.*;

/**
 * This program demonstrates anonymous inner classes.
 * @version 1.12 2017-12-14
 * @author Cay Horstmann
 */
public class AnonymousInnerClassTest
{
   public static void main(String[] args)
   {
      var clock = new TalkingClock();
      clock.start(1000, true);

      // keep program running until the 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)	//将TalkingClock构造器的参数interval和beep移至start方法中
   {
	 //匿名内部类
	  //创建一个实现ActionListener接口的类的新对象，需要实现的方法actionPerformed定义在括号{}内
      var listener = new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               System.out.println("At the tone, the time is "
                  + Instant.ofEpochMilli(event.getWhen()));
               if (beep) Toolkit.getDefaultToolkit().beep();	//actionPerformed方法执行if (beep)……
            }
         };
      var timer = new Timer(interval, listener);
      timer.start();
   }
}

运行结果：

实验程序3：

　　 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；

　　了解静态内部类的用法。

6-9源代码：

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)
   {
      var values = new double[20];
      for (int i = 0; i < values.length; i++)
         values[i] = 100 * Math.random();
      ArrayAlg.Pair p = ArrayAlg.minmax(values);	//将Pair定义为ArrayAlg的内部类，通过ArrayAlg.minmax访问
      System.out.println("min = " + p.getFirst());
      System.out.println("max = " + p.getSecond());
   }
}

//外部类
class ArrayAlg
{
   /**
    * A pair of floating-point numbers
    */
   public static class Pair		//Pair类
   {
	   //两个参数
      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()	//getFirst方法
      {
         return first;
      }

      /**
       * Returns the second number of the pair
       * @return the second number
       */
      public double getSecond()	//getSecond方法
      {
         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
    */
   //静态内部类
   public static Pair minmax(double[] values)
   {
      double min = Double.POSITIVE_INFINITY;
      double max = Double.NEGATIVE_INFINITY;
      for (double v : values)
      {
         if (min > v) min = v;
         if (max < v) max = v;
      }
      return new Pair(min, max);
   }
}

运行结果：

实验总结：

　　通过本次实验的学习，掌握了接口，Lambda表达式以及内部类的基本知识，对java有了一定的深入了解，但是在实际问题的解决当中依然有问题。编程实验起初不懂得如何着手，仍需要继续努力学习。通过实验结合知识的操作，掌握了些许的Java新知识点，但仍有许多不足之处，需要继续努力学习探究。