201771010112羅鬆《面向物件程式設計（java）》第十一週學習總結
阿新 • • 發佈：2018-11-11
1、實驗目的與要求
(1) 掌握Vetor、Stack、Hashtable三個類的用途及常用API；
(2) 瞭解java集合框架體系組成；
(3) 掌握ArrayList、LinkList兩個類的用途及常用API。
(4) 瞭解HashSet類、TreeSet類的用途及常用API。
(5)瞭解HashMap、TreeMap兩個類的用途及常用API；
(6) 結對程式設計（Pair programming）練習，體驗程式開發中的兩人合作。
2、實驗內容和步驟
實驗1： 匯入第9章示例程式，測試程式並進行程式碼註釋。
測試程式1：
l 使用JDK命令執行編輯、執行以下三個示例程式，結合執行結果理解程式；
掌握Vetor、Stack、Hashtable三個類的用途及常用API。
import java.util.Vector; //示例程式1 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();//建立一個新的類 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)// instanceof運算子是用來指出物件是否是特定類的一個例項 { ((Cat) cats.elementAt(i)).print(); }else { ((Dog) cats.elementAt(i)).print(); } }}
結果：
示例二：
//示例程式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]);//放入一個i值 System.out.println(stk); System.out.println("element 2=" + stk.elementAt(2));//element表示一個節點 while (!stk.empty()) System.out.println(stk.pop());//出棧操作 } } Stacks
結果：
示例三：
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();//生成集合類Hashtable for (int i = 0; i < 10000; i++) //生成迴圈體 { Integer r = new Integer((int) (Math.random() * 20));//隨機生成實數定義為整型 if (ht.containsKey(r)) ((Counter) ht.get(r)).i++;//用來判斷r是否為一個間值 else ht.put(r, new Counter());//建立新的Counter物件 } System.out.println(ht); } }
結果：
測試程式2：
l 使用JDK命令編輯執行ArrayListDemo和LinkedListDemo兩個程式，結合程式執行結果理解程式；
import java.util.*; public class ArrayListDemo { public static void main(String[] argv) { ArrayList al = new ArrayList(); //用Add來新增物件且可以過載 // 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")); System.out.println(al.size());//輸出al的長度 // 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)); } } } ArrayListDemo
mport 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");//add方法可以過載 ListIterator li = l.listIterator(0);//迭代器生成li物件 while (li.hasNext())//hasNext方法用來返回迭代器的物件 System.out.println(li.next()); if (l.indexOf("Hello") < 0) //生成迴圈語句判斷最後結果 System.err.println("Lookup does not work"); else System.err.println("Lookup works"); } } LinkedListDemo
測試程式3：
l 執行SetDemo程式，結合執行結果理解程式；
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()) //hasNext方法 { System.out.println(it.next()); } } } SetDemo
- 在Elipse環境下除錯教材365頁程式9-2，結合執行結果理解程式；瞭解HashSet類的用途及常用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<>(); // HashSet implements Set long totalTime = 0; try (Scanner in = new Scanner(System.in)) { while (in.hasNext())//迭代器的用法，判斷當前元素是否存在 { String word = in.next();//指向下一個元素 long callTime = System.currentTimeMillis(); words.add(word);// callTime = System.currentTimeMillis() - callTime; totalTime += callTime; } } Iterator<String> iter = words.iterator();//迭代器的簡單實現 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."); } }
小結：HashSet類中存放的物件不能重複，不能保證元素的排列順序，順序有可能發生變化。
在Elipse環境下除錯教材367頁-368程式9-3、9-4，結合程式執行結果理解程式；瞭解TreeSet類的用途及常用API。
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));//add方法 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); } } TreeSetTest
package treeSet; import java.util.*; /** * An item with a description and a part number. */ public class Item implements Comparable<Item>//Item類實現Comparable介面 { 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;//字串 partNumber = aPartNumber; } /** * Gets the description of this item. * * @return the description */ public String getDescription() { return description; } public String toString() { return "[description=" + description + ", partNumber=" + partNumber + "]"; }//返回該物件的字串表示 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); } } Item
小結：TreeSet是一種自帶排序的set，TreeSet可以確保集合元素處於排序狀態。TreeSet支援兩種排序方式，自然排序 和定製排序。
測試程式4：
使用JDK命令執行HashMapDemo程式，結合程式執行結果理解程式；
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");//定義物件 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); } }
l 在Elipse環境下除錯教材373頁程式9-6，結合程式執行結果理解程式；
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<>();//HashMap implements Map 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)); } }
l 實驗2：結對程式設計練習：
關於結對程式設計：以下圖片是一個結對程式設計場景：兩位學習夥伴坐在一起，面對著同一臺顯示器，使用著同一鍵盤，同一個滑鼠，他們一起思考問題，一起分析問題，一起編寫程式。
l 關於結對程式設計的闡述可參見以下連結：
http://www.cnblogs.com/xinz/archive/2011/08/07/2130332.html
http://en.wikipedia.org/wiki/Pair_programming
l 對於結對程式設計中程式碼設計規範的要求參考：
http://www.cnblogs.com/xinz/archive/2011/11/20/2255971.html
以下實驗，就讓我們來體驗一下結對程式設計的魅力
l 確定本次實驗結對程式設計合作伙伴；
l 各自執行合作伙伴實驗九程式設計練習1，結合使用體驗對所執行程式提出完善建議；
l 各自執行合作伙伴實驗十程式設計練習2，結合使用體驗對所執行程式提出完善建議；
1、合作伙伴：張雲飛
- 採用結對程式設計方式，與學習夥伴合作完成實驗九程式設計練習1；
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;//對集合進行排序、查詢、修改等； public class Test { private static ArrayList<Citizen> citizenlist; public static void main(String[] args) { citizenlist = new ArrayList<>(); Scanner scanner = new Scanner(System.in); File file = new File("E:/java/身份證號.txt"); //異常捕獲 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); // 將字串轉換成10進位制數 int ag = Integer.parseInt(age); citizen.setage(ag); citizen.setBirthplace(birthplace); citizenlist.add(citizen); } } catch (FileNotFoundException e) { System.out.println("資訊檔案找不到"); e.printStackTrace(); } catch (IOException e) { System.out.println("資訊檔案讀取錯誤"); e.printStackTrace(); } boolean isTrue = true; while (isTrue) { System.out.println("1.按姓名字典序輸出人員資訊"); System.out.println("2.查詢最大年齡的人員資訊、查詢最小年齡人員資訊"); System.out.println("3.查詢人員中是否查詢人員中是否有你的同鄉"); System.out.println("4.輸入你的年齡，查詢檔案中年齡與你最近人的姓名、身份證號、年齡、性別和出生地"); System.out.println("5.退出"); int nextInt = scanner.nextInt(); switch (nextInt) { case 1: Collections.sort(citizenlist); System.out.println(citizenlist.toString()); break; case 2: int max = 0, min = 100; int m, k1 = 0, k2 = 0; for (int i = 1; i < citizenlist.size(); i++) { m = citizenlist.get(i).getage(); if (m > max) { max = m; k1 = i; } if (m < min) { min = m; k2 = i; } } System.out.println("年齡最大：" + citizenlist.get(k1)); System.out.println("年齡最小：" + citizenlist.get(k2)); break; case 3: System.out.println("出生地："); String find = scanner.next(); String place = find.substring(0, 3); for (int i = 0; i < citizenlist.size(); i++) { if (citizenlist.get(i).getBirthplace().substring(1, 4).equals(place)) System.out.println("出生地" + citizenlist.get(i)); } break; case 4: System.out.println("年齡："); int yourage = scanner.nextInt(); int near = peer(yourage); int j = yourage - citizenlist.get(near).getage(); System.out.println("" + citizenlist.get(near)); break; case 5: isTrue = false; System.out.println("程式已退出!"); break; default: System.out.println("輸入有誤"); } } } public static int peer(int age) { int flag = 0; int min = 53, j = 0; for (int i = 0; i < citizenlist.size(); i++) { j = citizenlist.get(i).getage() - age; if (j < 0) j = -j; if (j < min) { min = j; flag = i; } } return flag; } } test
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"; } } citizen
l 各自執行合作伙伴實驗十程式設計練習2，結合使用體驗對所執行程式提出完善建議；
import java.io.FileNotFoundException; import java.io.IOException; import java.io.PrintWriter; import java.util.Scanner; public class calculator { public static void main(String[] args) { Scanner in = new Scanner(System.in); Count count=new Count(); PrintWriter out = null; try { out = new PrintWriter("test.txt"); int sum = 0; for (int i = 1; i <=10; i++) { int a = (int) Math.round(Math.random() * 100); int b = (int) Math.round(Math.random() * 100); int menu = (int) Math.round(Math.random() * 3); switch (menu) { case 0: System.out.println(i+":"+a + "+" + b + "="); int c1 = in.nextInt(); out.println(a + "+" + b + "=" + c1); if (c1 == (a + b)) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; case 1: while (a < b) { b = (int) Math.round(Math.random() * 100); } System.out.println(i+":"+a + "-" + b + "="); int c2 = in.nextInt(); out.println(a + "-" + b + "=" + c2); if (c2 == (a - b)) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; case 2: System.out.println(i+":"+a + "*" + b + "="); int c3 = in.nextInt(); out.println(a + "*" + b + "=" + c3); if (c3 == a * b) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; case 3: while(b == 0){ b = (int) Math.round(Math.random() * 100); } while(a % b != 0){ a = (int) Math.round(Math.random() * 100); } System.out.println(i+":"+a + "/" + b + "="); int c4 = in.nextInt(); if (c4 == a / b) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; } } System.out.println("你的得分為" + sum); out.println("你的得分為" + sum); out.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } } } calculate
public class Count<T> { private T a; private T b; public Count() { a=null; b=null; } public Count(T a,T b) { this.a=a; this.b=b; } public int count1(int a,int b) { return a+b; } public int count2(int a,int b) { return a-b; } public int count3(int a,int b) { return a*b; } public int count4(int a,int b) { return a/b; } } count
l 採用結對程式設計方式，與學習夥伴合作完成實驗九程式設計練習1；
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.List; import java.util.Scanner; public class Xinxi { private static ArrayList<Student> studentlist; public static void main(String[] args) { studentlist = new ArrayList<>(); Scanner scanner = new Scanner(System.in); File file = new File("D:\\身份證號\\身份證號.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 number = linescanner.next(); String sex = linescanner.next(); String age = linescanner.next(); String province = linescanner.nextLine(); Student student = new Student(); student.setName(name); student.setnumber(number); student.setsex(sex); int a = Integer.parseInt(age); student.setage(a); student.setprovince(province); studentlist.add(student); } } catch (FileNotFoundException e) {//新增的異常處理語句try{ }catch{ }語句 System.out.println("所找資訊檔案找不到"); e.printStackTrace(); } catch (IOException e) { System.out.println("所找資訊檔案讀取錯誤");//採取積極方法捕獲異常，並將異常返回自己所設定的列印文字 e.printStackTrace(); } boolean isTrue = true; while (isTrue) { System.out.println("選擇你的操作，輸入正確格式的選項"); System.out.println("1按姓名字典序輸出人員資訊"); System.out.println("2.查詢最大和最小年齡的人員資訊"); System.out.println("3.尋找年齡相近的人的資訊"); System.out.println("4.尋找老鄉"); System.out.println("5.退出"); String n = scanner.next(); switch (n) { case "1": Collections.sort(studentlist); System.out.println(studentlist.toString()); break; case "2": int max = 0, min = 100; int j, k1 = 0, k2 = 0; for (int i = 1; i < studentlist.size(); i++) { j = studentlist.get(i).getage(); if (j > max) { max = j; k1 = i; } if (j < min) { min = j; k2 = i; } } System.out.println("年齡最大：" + studentlist.get(k1)); System.out.println("年齡最小：" + studentlist.get(k2)); break; case "3": System.out.println("家鄉在哪裡？"); String find = scanner.next(); String place = find.substring(0, 3); for (int i = 0; i < studentlist.size(); i++) { if (studentlist.get(i).getprovince().substring(1, 4).equals(place)) System.out.println("同鄉" + studentlist.get(i)); } break; case "4": System.out.println("年齡："); int yourage = scanner.nextInt(); int near = agenear(yourage); int value = yourage - studentlist.get(near).getage(); System.out.println("" + studentlist.get(near)); break; case "5": isTrue = false; System.out.println("退出程式!"); break; default: System.out.println("輸入有誤"); } } } public static int agenear(int age) { int j = 0, min = 53, value = 0, flag = 0; for (int i = 0; i < studentlist.size(); i++) { value = studentlist.get(i).getage() - age; if (value < 0) value = -value; if (value < min) { min = value; flag = i; } } return flag; } } xinxi xinxi
public class Student implements Comparable<Student> { private String name; private String number; private String sex; private String province; private int age; public void setName(String name) { // TODO 自動生成的方法存根 this.name = name; } public String getName() { // TODO 自動生成的方法存根 return name; } public void setnumber(String number) { // TODO 自動生成的方法存根 this.number = number; } public String getNumber() { // TODO 自動生成的方法存根 return number; } public void setsex(String sex) { // TODO 自動生成的方法存根 this.sex = sex; } public String getsex() { // TODO 自動生成的方法存根 return sex; } public void setprovince(String province) { // TODO 自動生成的方法存根 this.province = province; } public String getprovince() { // TODO 自動生成的方法存根 return province; } public void setage(int a) { // TODO 自動生成的方法存根 this.age = age; } public int getage() { // TODO 自動生成的方法存根 return age; } public int compareTo(Student o) { return this.name.compareTo(o.getName()); } public String toString() { return name + "\t" + sex + "\t" + age + "\t" + number + "\t" + province + "\n"; } } student類 student
l 採用結對程式設計方式，與學習夥伴合作完成實驗十程式設計練習2。
import java.io.FileNotFoundException; import java.io.IOException; import java.io.PrintWriter; import java.util.Scanner; public class calculator { public static void main(String[] args) { Scanner in = new Scanner(System.in); Count count=new Count(); PrintWriter out = null; try { out = new PrintWriter("test.txt"); int sum = 0; for (int i = 1; i <=10; i++) { int a = (int) Math.round(Math.random() * 100); int b = (int) Math.round(Math.random() * 100); int menu = (int) Math.round(Math.random() * 3); switch (menu) { case 0: System.out.println(i+":"+a + "+" + b + "="); int c1 = in.nextInt(); out.println(a + "+" + b + "=" + c1); if (c1 == (a + b)) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; case 1: while (a < b) { b = (int) Math.round(Math.random() * 100); } System.out.println(i+":"+a + "-" + b + "="); int c2 = in.nextInt(); out.println(a + "-" + b + "=" + c2); if (c2 == (a - b)) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; case 2: System.out.println(i+":"+a + "*" + b + "="); int c3 = in.nextInt(); out.println(a + "*" + b + "=" + c3); if (c3 == a * b) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; case 3: while(b == 0){ b = (int) Math.round(Math.random() * 100); } while(a % b != 0){ a = (int) Math.round(Math.random() * 100); } System.out.println(i+":"+a + "/" + b + "="); int c4 = in.nextInt(); if (c4 == a / b) { sum += 10; System.out.println("恭喜答案正確"); } else { System.out.println("抱歉，答案錯誤"); } break; } } System.out.println("你的得分為" + sum); out.println("你的得分為" + sum); out.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } } } calculate
public class Count<T> { private T a; private T b; public Count() { a=null; b=null; } public Count(T a,T b) { this.a=a; this.b=b; } public int count1(int a,int b) { return a+b; } public int count2(int a,int b) { return a-b; } public int count3(int a,int b) { return a*b; } public int count4(int a,int b) { return a/b; } } count
實驗總結：
通過這周的學習，我對Vetor、Stack、Hashtable三個類的用途及常用API有了大致的瞭解，還大致瞭解了java集合框架體系組成；基本 掌握ArrayList、LinkList兩個類的用途及常用API。瞭解了HashSet類、TreeSet類的用途及常用API和HashMap、TreeMap兩個類的用途及常用API；
不過上述這些都只是有了一個初步的瞭解，要做到運用自如還要深入研究，苦下功夫。這周學習還有個最大的不同就是體驗了程式開發中兩人合作的感覺，從有意見不同到最後解決，那個過程很讓人享受，有種競爭感和成就感，總之這周收穫很大，今後的學習會更加努力！