王之泰/王志成《面向对象程序设计（java）》第十一周学习总结

第一部分：理论知识学习部分

第十一章理论知识主要为集合类的介绍，在实验中都有所体现且本周主要复习回顾上周的泛型程序设计

第二部分：实验部分 ——集合

1、实验目的与要求

(1) 掌握Vetor、Stack、Hashtable三个类的用途及常用API；

(2) 了解java集合框架体系组成；

(3) 掌握ArrayList、LinkList两个类的用途及常用API。

(4) 了解HashSet类、TreeSet类的用途及常用API。

(5)了解HashMap、TreeMap两个类的用途及常用API；

(6) 结对编程（Pair programming）练习，体验程序开发中的两人合作。

2、实验内容和步骤

实验1： 导入第9章示例程序，测试程序并进行代码注释。

测试程序1：

1.使用JDK命令运行编辑、运行以下三个示例程序，结合运行结果理解程序；

2.掌握Vetor、Stack、Hashtable三个类的用途及常用API。 

//示例程序1
import java.util.Vector;

class Cat {
    private int catNumber;

    Cat(int i) {
        catNumber = i;
    }

    void print() {
        System.out.println("Cat #" + catNumber);
    }
}

class Dog {
    private int dogNumber;

    Dog(int i) {
        dogNumber = i;
    }

    void print() {
        System.out.println("Dog #" + dogNumber);
    }
}

public class CatsAndDogs {
    public static void main(String[] args) {
        Vector cats = new Vector();
        for (int i = 0; i < 7; i++)
            cats.addElement(new Cat(i));
        cats.addElement(new Dog(7));
        for (int i = 0; i < cats.size(); i++)
            ((Cat) cats.elementAt(i)).print();
    }
} 

结果如下：

处理后：

package shi_li;

import java.util.Vector;

class Cat {
    private int catNumber;

    Cat(int i) {
        catNumber = i;
    }

    void print() {
        System.out.println("Cat #" + catNumber);
    }
}

class Dog {
    private int dogNumber;

    Dog(int i) {
        dogNumber = i;
    }

    void print() {
        System.out.println("Dog #" + dogNumber);
    }
}

public class CatsAndDogs {
    public static void main(String[] args) {
        Vector cats = new Vector();
        for (int i = 0; i < 7; i++)
            cats.addElement(new Cat(i));
        cats.addElement(new Dog(7));
        for (int i = 0; i <cats.size(); i++) {
            if(cats.elementAt(i) instanceof Cat) {
            ((Cat) cats.elementAt(i)).print();
            }
            else {
                ((Dog) cats.elementAt(i)).print();
            }
                
            }
}
}

//示例程序2
import java.util.*;

public class Stacks {
    static String[] months = { "1", "2", "3", "4" };

    public static void main(String[] args) {
        Stack stk = new Stack();
        for (int i = 0; i < months.length; i++)
            stk.push(months[i]);
        System.out.println(stk);
        System.out.println("element 2=" + stk.elementAt(2));
        while (!stk.empty())
            System.out.println(stk.pop());
    }
}

//示例程序3
import java.util.*;

class Counter {
    int i = 1;

    public String toString() {
        return Integer.toString(i);
    }
}

public class Statistics {
    public static void main(String[] args) {
        Hashtable ht = new Hashtable();
        for (int i = 0; i < 10000; i++) {
            Integer r = new Integer((int) (Math.random() * 20));
            if (ht.containsKey(r))
                ((Counter) ht.get(r)).i++;
            else
                ht.put(r, new Counter());
        }
        System.out.println(ht);
    }
}

测试程序2：

1.使用JDK命令编辑运行ArrayListDemo和LinkedListDemo两个程序，结合程序运行结果理解程序；

import java.util.*;

public class ArrayListDemo {
    public static void main(String[] argv) {
        ArrayList al = new ArrayList();
        // Add lots of elements to the ArrayList...
        al.add(new Integer(11));
        al.add(new Integer(12));
        al.add(new Integer(13));
        al.add(new String("hello"));
        // First print them out using a for loop.
        System.out.println("Retrieving by index:");
        for (int i = 0; i < al.size(); i++) {
            System.out.println("Element " + i + " = " + al.get(i));
        }
    }
}

import java.util.*;
public class LinkedListDemo {
    public static void main(String[] argv) {
        LinkedList l = new LinkedList();
        l.add(new Object());
        l.add("Hello");
        l.add("zhangsan");
        ListIterator li = l.listIterator(0);
        while (li.hasNext())
            System.out.println(li.next());
        if (l.indexOf("Hello") < 0)   
            System.err.println("Lookup does not work");
        else
            System.err.println("Lookup works");
   }
}

2.在Elipse环境下编辑运行调试教材360页程序9-1，结合程序运行结果理解程序；

package linkedList;

import java.util.*;

/**
 * This program demonstrates operations on linked lists.
 * @version 1.11 2012-01-26
 * @author Cay Horstmann
 */
public class LinkedListTest
{
   public static void main(String[] args)
   {
      List<String> a = new LinkedList<>();
      a.add("Amy");
      a.add("Carl");
      a.add("Erica");

      List<String> b = new LinkedList<>();
      b.add("Bob");
      b.add("Doug");
      b.add("Frances");
      b.add("Gloria");

      // 将单词从B合并为A

      ListIterator<String> aIter = a.listIterator();
      Iterator<String> bIter = b.iterator();

      while (bIter.hasNext())
      {
         if (aIter.hasNext()) aIter.next();
         aIter.add(bIter.next());
      }

      System.out.println(a);

      // 从B中删除每个第二个单词

      bIter = b.iterator();
      while (bIter.hasNext())
      {
         bIter.next(); // 跳过一个元素
         if (bIter.hasNext())
         {
            bIter.next(); // 跳过下一个元素
            bIter.remove(); // 删除该元素
         }
      }

      System.out.println(b);

      // 批量操作：从A中删除B中的所有单词

      a.removeAll(b);

      System.out.println(a);
   }
}

3.掌握ArrayList、LinkList两个类的用途及常用API。

测试程序3：

1.运行SetDemo程序，结合运行结果理解程序；

import java.util.*;
public class SetDemo {
    public static void main(String[] argv) {
        HashSet h = new HashSet(); //也可以 Set h=new HashSet()
        h.add("One");
        h.add("Two");
        h.add("One"); // DUPLICATE
        h.add("Three");
        Iterator it = h.iterator();
        while (it.hasNext()) {
             System.out.println(it.next());
        }
    }
}

2.在Elipse环境下调试教材365页程序9-2，结合运行结果理解程序；了解HashSet类的用途及常用API。

package set;

import java.util.*;

/**
 * This program uses a set to print all unique words in System.in.
 * @version 1.12 2015-06-21
 * @author Cay Horstmann
 */
public class SetTest
{
   public static void main(String[] args)
   {
      Set<String> words = new HashSet<>(); //  SETHASSET实现
      long totalTime = 0;

      try (Scanner in = new Scanner(System.in))
      {
         while (in.hasNext())
         {
            String word = in.next();
            long callTime = System.currentTimeMillis();
            words.add(word);
            callTime = System.currentTimeMillis() - callTime;
            totalTime += callTime;
         }
      }

      Iterator<String> iter = words.iterator();
      for (int i = 1; i <= 20 && iter.hasNext(); i++)
         System.out.println(iter.next());
      System.out.println(". . .");
      System.out.println(words.size() + " distinct words. " + totalTime + " milliseconds.");
   }
}

3.在Elipse环境下调试教材367页-368程序9-3、9-4，结合程序运行结果理解程序；了解TreeSet类的用途及常用API。

package treeSet;

import java.util.*;

/**
 * An item with a description and a part number.
 */
public class Item implements Comparable<Item>
{
   private String description;
   private int partNumber;

   /**
    * Constructs an item.
    * 
    * @param aDescription
    *           the item's description
    * @param aPartNumber
    *           the item's part number
    */
   public Item(String aDescription, int aPartNumber)
   {
      description = aDescription;
      partNumber = aPartNumber;
   }

   /**
    * Gets the description of this item.
    * 
    * @return the description
    */
   public String getDescription()
   {
      return description;
   }

   public String toString()
   {
      return "[description=" + description + ", partNumber=" + partNumber + "]";
   }

   public boolean equals(Object otherObject)
   {
      if (this == otherObject) return true;
      if (otherObject == null) return false;
      if (getClass() != otherObject.getClass()) return false;
      Item other = (Item) otherObject;
      return Objects.equals(description, other.description) && partNumber == other.partNumber;
   }

   public int hashCode()
   {
      return Objects.hash(description, partNumber);
   }

   public int compareTo(Item other)
   {
      int diff = Integer.compare(partNumber, other.partNumber);
      return diff != 0 ? diff : description.compareTo(other.description);
   }
}

package treeSet;

import java.util.*;

/**
 * This program sorts a set of item by comparing their descriptions.
 * @version 1.12 2015-06-21
 * @author Cay Horstmann
 */
public class TreeSetTest
{
   public static void main(String[] args)
   {
      SortedSet<Item> parts = new TreeSet<>();
      parts.add(new Item("Toaster", 1234));
      parts.add(new Item("Widget", 4562));
      parts.add(new Item("Modem", 9912));
      System.out.println(parts);

      NavigableSet<Item> sortByDescription = new TreeSet<>(
            Comparator.comparing(Item::getDescription));

      sortByDescription.addAll(parts);
      System.out.println(sortByDescription);
   }
}

测试程序4：

1.使用JDK命令运行HashMapDemo程序，结合程序运行结果理解程序；

import java.util.*;
public class HashMapDemo {
   public static void main(String[] argv) {
      HashMap h = new HashMap();
      // The hash maps from company name to address.
      h.put("Adobe", "Mountain View, CA");
      h.put("IBM", "White Plains, NY");
      h.put("Sun", "Mountain View, CA");
      String queryString = "Adobe";
      String resultString = (String)h.get(queryString);
      System.out.println("They are located in: " +  resultString);
  }
}

2.在Elipse环境下调试教材373页程序9-6，结合程序运行结果理解程序；

package map;

/**
 * A minimalist employee class for testing purposes.
 */
public class Employee
{
   private String name;
   private double salary;

   /**
    * Constructs an employee with $0 salary.
    * @param n the employee name
    */
   public Employee(String name)
   {
      this.name = name;
      salary = 0;
   }

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

package map;

import java.util.*;

/**
 * This program demonstrates the use of a map with key type String and value type Employee.
 * @version 1.12 2015-06-21
 * @author Cay Horstmann
 */
public class MapTest
{
   public static void main(String[] args)
   {
      Map<String, Employee> staff = new HashMap<>();
      staff.put("144-25-5464", new Employee("Amy Lee"));
      staff.put("567-24-2546", new Employee("Harry Hacker"));
      staff.put("157-62-7935", new Employee("Gary Cooper"));
      staff.put("456-62-5527", new Employee("Francesca Cruz"));

      // print all entries

      System.out.println(staff);

      // remove an entry

      staff.remove("567-24-2546");

      // replace an entry

      staff.put("456-62-5527", new Employee("Francesca Miller"));

      // look up a value

      System.out.println(staff.get("157-62-7935"));

      // iterate through all entries

      staff.forEach((k, v) -> 
         System.out.println("key=" + k + ", value=" + v));
   }
}

3.了解HashMap、TreeMap两个类的用途及常用API。

实验2：结对编程练习：

1.关于结对编程：以下图片是一个结对编程场景：两位学习伙伴坐在一起，面对着同一台显示器，使用着同一键盘，同一个鼠标，他们一起思考问题，一起分析问题，一起编写程序。

2.关于结对编程的阐述可参见以下链接：

http://www.cnblogs.com/xinz/archive/2011/08/07/2130332.html

http://en.wikipedia.org/wiki/Pair_programming

3.对于结对编程中代码设计规范的要求参考：

http://www.cnblogs.com/xinz/archive/2011/11/20/2255971.html

以下实验，就让我们来体验一下结对编程的魅力。

1.确定本次实验结对编程合作伙伴；

我的小伙伴为：王志成

2.各自运行合作伙伴实验九编程练习1，结合使用体验对所运行程序提出完善建议；

3.各自运行合作伙伴实验十编程练习2，结合使用体验对所运行程序提出完善建议；

程序互测概述：

　　我和小伙伴互相测试了对方的实验九编程练习1程序，小伙伴的程序基本要求都能达到，就是在文件的读取上面还有些欠缺，但是在后面的共同学习中他很好的改了过来。实验十编程练习2中基本功能要求也同样能实现，只是在除法上面有点缺陷没有很好地实现实数运算。

程序互测心得：

　　通过本次和小伙伴的程序互测体验，其好处在于帮助别人发现问题的同时还可反思自己的程序，认识自己的不足。而且很有效的提升了自己阅读代码的能力。

4.采用结对编程方式，与学习伙伴合作完成实验九编程练习1；

结对编程代码；

package jiedui_bianchen;

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.Scanner;
import java.util.Collections;

public class ID {

    public static People findPeopleByname(String name) {
        People flag = null;
        for (People people : peoplelist) {
            if(people.getName().equals(name)) {
                flag = people;
            }
        }
        return flag;

    }

    public static People findPeopleByid(String id) {
        People flag = null;
        for (People people : peoplelist) {
            if(people.getnumber().equals(id)) {
                flag = people;
            }
        }
        return flag;

    }
     
    private static ArrayList<People> agenear(int yourage) {
        // TODO Auto-generated method stub
        int j=0,min=53,d_value=0,k = 0;
        ArrayList<People> plist = new ArrayList<People>();
        for (int i = 0; i < peoplelist.size(); i++) {
            d_value = peoplelist.get(i).getage() > yourage ? 
                    peoplelist.get(i).getage() - yourage : yourage - peoplelist.get(i).getage() ;
            k = d_value < min ? i : k;
            min = d_value < min ? d_value : min;
        }
        for(People people : peoplelist) {
            if(people.getage() == peoplelist.get(k).getage()) {
                plist.add(people);
            }
        }
        return plist;
    }

    private static ArrayList<People> peoplelist; 
    
    public static void main(String[] args) //throws  IOException
    {
        peoplelist = new ArrayList<People>();
        Scanner scanner = new Scanner(System.in);
        File file = new File("D:\身份证号.txt");
        try {
            FileInputStream files = new FileInputStream(file);
            BufferedReader in = new BufferedReader(new InputStreamReader(files));
            String temp = null;
            while ((temp = in.readLine()) != null) {
                
                String[] information = temp.split("[ ]+");
                People people = new People();
                people.setName(information[0]);
                people.setnumber(information[1]);
                int A = Integer.parseInt(information[3]);
                people.setage(A);
                people.setsex(information[2]);
                for(int j = 4; j<information.length;j++) {
                    people.setplace(information[j]);
                }
                peoplelist.add(people);

            }
        } catch (FileNotFoundException e) {
            System.out.println("文件未找到");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("文件读取错误");
            e.printStackTrace();
        }
        boolean isTrue = true;
        while (isTrue) {

            System.out.println("******************************************");
            System.out.println("   1.按姓名典序输出人员信息");
            System.out.println("   2.查询最大年龄人员信息");
            System.out.println("   3.查询最小年龄人员信息");
            System.out.println("   4.输入你的年龄，查询身份证号.txt中年龄与你最近的人");
            System.out.println("   5.查询人员中是否有你的同乡");
            System.out.println("   6.退出");
            System.out.println("******************************************");
            int nextInt = scanner.nextInt();
            switch (nextInt) {
            case 1:
                Collections.sort(peoplelist);
                System.out.println(peoplelist.toString());
                break;
            case 2:
                int max=0;
                int j,k1 = 0;
                for(int i=1;i<peoplelist.size();i++)
                {
                    j = peoplelist.get(i).getage();
                   if(j>max)
                   {
                       max = j; 
                       k1 = i;
                   }
                  
                }  
                System.out.println("年龄最大："+peoplelist.get(k1));
                break;
            case 3:
                int min = 100;
                int j1,k2 = 0;
                for(int i=1;i<peoplelist.size();i++)
                {
                    j1 = peoplelist.get(i).getage();
                    if(j1<min)
                    {
                        min = j1; 
                        k2 = i;
                    }

                 } 
                System.out.println("年龄最小："+peoplelist.get(k2));
                break;
            case 4:
                System.out.println("年龄：");
                int input_age = scanner.nextInt();
                ArrayList<People> plist = new ArrayList<People>();
                plist = agenear(input_age);
                for(People people : plist) {
                    System.out.println(people.toString());
                }
                break;
            case 5:
                System.out.println("请输入省份");
                String find = scanner.next();        
                for (int i = 0; i <peoplelist.size(); i++) 
                {
                    String [] place = peoplelist.get(i).getplace().split("	");
                    for(String temp : place) {
                        if(find.equals(temp)) {
                            System.out.println("你的同乡是    "+peoplelist.get(i));
                            break;
                        }
                    }
                    
                } 
                break;
            case 6:
                isTrue = false;
                System.out.println("byebye!");
                break;
            default:
                System.out.println("输入有误");
            }
        }
    }

}

结对程序运行功能界面截图；

结对过程描述，提供两人在讨论、细化和编程时的结对照片(非摆拍)。

 

 

5.采用结对编程方式，与学习伙伴合作完成实验十编程练习2。

结对编程代码；

import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.util.Scanner;


public class ss {
    public static void main(String[] args) {


        Scanner in = new Scanner(System.in);
        Calculator<Integer> sf = new Calculator<Integer>();
        File file = new File("wzt.txt");
        if(file.exists()) {
            System.out.println("文件已存在");
        }
        PrintWriter output = null;
        try {
            output = new PrintWriter(new FileOutputStream(file));
        } catch (Exception e) {
            //e.printStackTrace();
        }
        int sum = 0;
        
        System.out.println("计算结果保留两位小数");
        for (int i = 1; i < 11; i++) {
            int a = (int) Math.round(Math.random() * 100);
                int b = (int) Math.round(Math.random() * 100);
                int s = (int) Math.round(Math.random() * 3);

            
           switch(s)
           {
           case 1:
               System.out.println(i+": "+a+"/"+b+"=");
               Number c = in.nextDouble();
               output.println(a+"/"+b+"="+c);
               Number g = sf.division(a, b);
               BigDecimal division = new BigDecimal(g.doubleValue());
               g = division.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
               if (c.equals(g)) {
                   sum += 10;
                   System.out.println("恭喜答案正确");
               }
               else {
                   System.out.println("抱歉，答案错误");
               }
            
               break;
            
           case 2:
               System.out.println(i+": "+a+"*"+b+"=");
               Number c1 = in.nextDouble();
               output.println(a+"*"+b+"="+c1);
               Number g1 = sf.mulitiplication(a, b);
               BigDecimal mul = new BigDecimal(g1.doubleValue());
               g1 = mul.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
               if (c1.equals(g1) ){
                   sum += 10;
                   System.out.println("恭喜答案正确");
               }
               else {
                   System.out.println("抱歉，答案错误");
               }
               break;
           case 3:
               System.out.println(i+": "+a+"+"+b+"=");
               Number c2 = in.nextDouble();
               output.println(a+"+"+b+"="+c2);
               Number g2 =sf.addition(a, b);
               BigDecimal add = new BigDecimal(g2.doubleValue());
               g2 = add.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
               if (c2.equals(g2)) {
                   sum += 10;
                   System.out.println("恭喜答案正确");
               }
               else {
                   System.out.println("抱歉，答案错误");
               }
               
               break ;
           case 4:
               System.out.println(i+": "+a+"-"+b+"=");
               Number c3 = in.nextDouble();
               output.println(a+"-"+b+"="+c3);
               Number g3 = sf.subtraction(a, b);
               BigDecimal sub = new BigDecimal(g3.doubleValue());
               g3 = sub.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
               if (c3.equals(g3)) {
                   sum += 10;
                   System.out.println("恭喜答案正确");
               }
               else {
                   System.out.println("抱歉，答案错误");
               }
               break ;

               } 
    
          }
        System.out.println("成绩"+sum);
        output.println("成绩:"+sum);
        output.close();
        in.close();
         
    }
}

结对程序运行功能界面截图；

结对过程描述，提供两人在讨论、细化和编程时的结对照片(非摆拍)。

 

 

 

第三部分：总结

　　在本周的学习过程中，复习了上周内容即泛型程序设计的知识，学习了新的关于集合类的知识，理解了一些常用API的用途。在实验方面通过结对编程，在小伙伴的帮助下认识了自己的不足，提升了自己的阅读代码的能力。