王之泰/王志成《面向对象程序设计（java）》第十一周学习总结
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2022-03-18 15:50:41
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) ......
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。
1 //示例程序1
2 import java.util.vector;
3
4 class cat {
5 private int catnumber;
6
7 cat(int i) {
8 catnumber = i;
9 }
10
11 void print() {
12 system.out.println("cat #" + catnumber);
13 }
14 }
15
16 class dog {
17 private int dognumber;
18
19 dog(int i) {
20 dognumber = i;
21 }
22
23 void print() {
24 system.out.println("dog #" + dognumber);
25 }
26 }
27
28 public class catsanddogs {
29 public static void main(string[] args) {
30 vector cats = new vector();
31 for (int i = 0; i < 7; i++)
32 cats.addelement(new cat(i));
33 cats.addelement(new dog(7));
34 for (int i = 0; i < cats.size(); i++)
35 ((cat) cats.elementat(i)).print();
36 }
37 }
结果如下：
处理后：
1 package shi_li;
2
3 import java.util.vector;
4
5 class cat {
6 private int catnumber;
7
8 cat(int i) {
9 catnumber = i;
10 }
11
12 void print() {
13 system.out.println("cat #" + catnumber);
14 }
15 }
16
17 class dog {
18 private int dognumber;
19
20 dog(int i) {
21 dognumber = i;
22 }
23
24 void print() {
25 system.out.println("dog #" + dognumber);
26 }
27 }
28
29 public class catsanddogs {
30 public static void main(string[] args) {
31 vector cats = new vector();
32 for (int i = 0; i < 7; i++)
33 cats.addelement(new cat(i));
34 cats.addelement(new dog(7));
35 for (int i = 0; i <cats.size(); i++) {
36 if(cats.elementat(i) instanceof cat) {
37 ((cat) cats.elementat(i)).print();
38 }
39 else {
40 ((dog) cats.elementat(i)).print();
41 }
42
43 }
44 }
45 }
1 //示例程序2
2 import java.util.*;
3
4 public class stacks {
5 static string[] months = { "1", "2", "3", "4" };
6
7 public static void main(string[] args) {
8 stack stk = new stack();
9 for (int i = 0; i < months.length; i++)
10 stk.push(months[i]);
11 system.out.println(stk);
12 system.out.println("element 2=" + stk.elementat(2));
13 while (!stk.empty())
14 system.out.println(stk.pop());
15 }
16 }
1 //示例程序3
2 import java.util.*;
3
4 class counter {
5 int i = 1;
6
7 public string tostring() {
8 return integer.tostring(i);
9 }
10 }
11
12 public class statistics {
13 public static void main(string[] args) {
14 hashtable ht = new hashtable();
15 for (int i = 0; i < 10000; i++) {
16 integer r = new integer((int) (math.random() * 20));
17 if (ht.containskey(r))
18 ((counter) ht.get(r)).i++;
19 else
20 ht.put(r, new counter());
21 }
22 system.out.println(ht);
23 }
24 }
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；
1 import java.util.*;
2
3 public class arraylistdemo {
4 public static void main(string[] argv) {
5 arraylist al = new arraylist();
6 // add lots of elements to the arraylist...
7 al.add(new integer(11));
8 al.add(new integer(12));
9 al.add(new integer(13));
10 al.add(new string("hello"));
11 // first print them out using a for loop.
12 system.out.println("retrieving by index:");
13 for (int i = 0; i < al.size(); i++) {
14 system.out.println("element " + i + " = " + al.get(i));
15 }
16 }
17 }
1 import java.util.*;
2 public class linkedlistdemo {
3 public static void main(string[] argv) {
4 linkedlist l = new linkedlist();
5 l.add(new object());
6 l.add("hello");
7 l.add("zhangsan");
8 listiterator li = l.listiterator(0);
9 while (li.hasnext())
10 system.out.println(li.next());
11 if (l.indexof("hello") < 0)
12 system.err.println("lookup does not work");
13 else
14 system.err.println("lookup works");
15 }
16 }
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；
1 package linkedlist;
2
3 import java.util.*;
4
5 /**
6 * this program demonstrates operations on linked lists.
7 * @version 1.11 2012-01-26
8 * @author cay horstmann
9 */
10 public class linkedlisttest
11 {
12 public static void main(string[] args)
13 {
14 list<string> a = new linkedlist<>();
15 a.add("amy");
16 a.add("carl");
17 a.add("erica");
18
19 list<string> b = new linkedlist<>();
20 b.add("bob");
21 b.add("doug");
22 b.add("frances");
23 b.add("gloria");
24
25 // 将单词从b合并为a
26
27 listiterator<string> aiter = a.listiterator();
28 iterator<string> biter = b.iterator();
29
30 while (biter.hasnext())
31 {
32 if (aiter.hasnext()) aiter.next();
33 aiter.add(biter.next());
34 }
35
36 system.out.println(a);
37
38 // 从b中删除每个第二个单词
39
40 biter = b.iterator();
41 while (biter.hasnext())
42 {
43 biter.next(); // 跳过一个元素
44 if (biter.hasnext())
45 {
46 biter.next(); // 跳过下一个元素
47 biter.remove(); // 删除该元素
48 }
49 }
50
51 system.out.println(b);
52
53 // 批量操作：从a中删除b中的所有单词
54
55 a.removeall(b);
56
57 system.out.println(a);
58 }
59 }
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；
1 import java.util.*;
2 public class setdemo {
3 public static void main(string[] argv) {
4 hashset h = new hashset(); //也可以 set h=new hashset()
5 h.add("one");
6 h.add("two");
7 h.add("one"); // duplicate
8 h.add("three");
9 iterator it = h.iterator();
10 while (it.hasnext()) {
11 system.out.println(it.next());
12 }
13 }
14 }
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。
1 package set;
2
3 import java.util.*;
4
5 /**
6 * this program uses a set to print all unique words in system.in.
7 * @version 1.12 2015-06-21
8 * @author cay horstmann
9 */
10 public class settest
11 {
12 public static void main(string[] args)
13 {
14 set<string> words = new hashset<>(); // sethasset实现
15 long totaltime = 0;
16
17 try (scanner in = new scanner(system.in))
18 {
19 while (in.hasnext())
20 {
21 string word = in.next();
22 long calltime = system.currenttimemillis();
23 words.add(word);
24 calltime = system.currenttimemillis() - calltime;
25 totaltime += calltime;
26 }
27 }
28
29 iterator<string> iter = words.iterator();
30 for (int i = 1; i <= 20 && iter.hasnext(); i++)
31 system.out.println(iter.next());
32 system.out.println(". . .");
33 system.out.println(words.size() + " distinct words. " + totaltime + " milliseconds.");
34 }
35 }
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。
1 package treeset;
2
3 import java.util.*;
4
5 /**
6 * an item with a description and a part number.
7 */
8 public class item implements comparable<item>
9 {
10 private string description;
11 private int partnumber;
12
13 /**
14 * constructs an item.
15 *
16 * @param adescription
17 * the item's description
18 * @param apartnumber
19 * the item's part number
20 */
21 public item(string adescription, int apartnumber)
22 {
23 description = adescription;
24 partnumber = apartnumber;
25 }
26
27 /**
28 * gets the description of this item.
29 *
30 * @return the description
31 */
32 public string getdescription()
33 {
34 return description;
35 }
36
37 public string tostring()
38 {
39 return "[description=" + description + ", partnumber=" + partnumber + "]";
40 }
41
42 public boolean equals(object otherobject)
43 {
44 if (this == otherobject) return true;
45 if (otherobject == null) return false;
46 if (getclass() != otherobject.getclass()) return false;
47 item other = (item) otherobject;
48 return objects.equals(description, other.description) && partnumber == other.partnumber;
49 }
50
51 public int hashcode()
52 {
53 return objects.hash(description, partnumber);
54 }
55
56 public int compareto(item other)
57 {
58 int diff = integer.compare(partnumber, other.partnumber);
59 return diff != 0 ? diff : description.compareto(other.description);
60 }
61 }
1 package treeset;
2
3 import java.util.*;
4
5 /**
6 * this program sorts a set of item by comparing their descriptions.
7 * @version 1.12 2015-06-21
8 * @author cay horstmann
9 */
10 public class treesettest
11 {
12 public static void main(string[] args)
13 {
14 sortedset<item> parts = new treeset<>();
15 parts.add(new item("toaster", 1234));
16 parts.add(new item("widget", 4562));
17 parts.add(new item("modem", 9912));
18 system.out.println(parts);
19
20 navigableset<item> sortbydescription = new treeset<>(
21 comparator.comparing(item::getdescription));
22
23 sortbydescription.addall(parts);
24 system.out.println(sortbydescription);
25 }
26 }
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；
1 import java.util.*;
2 public class hashmapdemo {
3 public static void main(string[] argv) {
4 hashmap h = new hashmap();
5 // the hash maps from company name to address.
6 h.put("adobe", "mountain view, ca");
7 h.put("ibm", "white plains, ny");
8 h.put("sun", "mountain view, ca");
9 string querystring = "adobe";
10 string resultstring = (string)h.get(querystring);
11 system.out.println("they are located in: " + resultstring);
12 }
13 }
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；
1 package map;
2
3 /**
4 * a minimalist employee class for testing purposes.
5 */
6 public class employee
7 {
8 private string name;
9 private double salary;
10
11 /**
12 * constructs an employee with $0 salary.
13 * @param n the employee name
14 */
15 public employee(string name)
16 {
17 this.name = name;
18 salary = 0;
19 }
20
21 public string tostring()
22 {
23 return "[name=" + name + ", salary=" + salary + "]";
24 }
25 }
1 package map;
2
3 import java.util.*;
4
5 /**
6 * this program demonstrates the use of a map with key type string and value type employee.
7 * @version 1.12 2015-06-21
8 * @author cay horstmann
9 */
10 public class maptest
11 {
12 public static void main(string[] args)
13 {
14 map<string, employee> staff = new hashmap<>();
15 staff.put("144-25-5464", new employee("amy lee"));
16 staff.put("567-24-2546", new employee("harry hacker"));
17 staff.put("157-62-7935", new employee("gary cooper"));
18 staff.put("456-62-5527", new employee("francesca cruz"));
19
20 // print all entries
21
22 system.out.println(staff);
23
24 // remove an entry
25
26 staff.remove("567-24-2546");
27
28 // replace an entry
29
30 staff.put("456-62-5527", new employee("francesca miller"));
31
32 // look up a value
33
34 system.out.println(staff.get("157-62-7935"));
35
36 // iterate through all entries
37
38 staff.foreach((k, v) ->
39 system.out.println("key=" + k + ", value=" + v));
40 }
41 }
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://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：
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；
1 package jiedui_bianchen;
2
3 import java.io.bufferedreader;
4 import java.io.file;
5 import java.io.fileinputstream;
6 import java.io.filenotfoundexception;
7 import java.io.ioexception;
8 import java.io.inputstreamreader;
9 import java.util.arraylist;
10 import java.util.scanner;
11 import java.util.collections;
12
13 public class id {
14
15 public static people findpeoplebyname(string name) {
16 people flag = null;
17 for (people people : peoplelist) {
18 if(people.getname().equals(name)) {
19 flag = people;
20 }
21 }
22 return flag;
23
24 }
25
26 public static people findpeoplebyid(string id) {
27 people flag = null;
28 for (people people : peoplelist) {
29 if(people.getnumber().equals(id)) {
30 flag = people;
31 }
32 }
33 return flag;
34
35 }
36
37 private static arraylist<people> agenear(int yourage) {
38 // todo auto-generated method stub
39 int j=0,min=53,d_value=0,k = 0;
40 arraylist<people> plist = new arraylist<people>();
41 for (int i = 0; i < peoplelist.size(); i++) {
42 d_value = peoplelist.get(i).getage() > yourage ?
43 peoplelist.get(i).getage() - yourage : yourage - peoplelist.get(i).getage() ;
44 k = d_value < min ? i : k;
45 min = d_value < min ? d_value : min;
46 }
47 for(people people : peoplelist) {
48 if(people.getage() == peoplelist.get(k).getage()) {
49 plist.add(people);
50 }
51 }
52 return plist;
53 }
54
55 private static arraylist<people> peoplelist;
56
57 public static void main(string[] args) //throws ioexception
58 {
59 peoplelist = new arraylist<people>();
60 scanner scanner = new scanner(system.in);
61 file file = new file("d:\\身份证号.txt");
62 try {
63 fileinputstream files = new fileinputstream(file);
64 bufferedreader in = new bufferedreader(new inputstreamreader(files));
65 string temp = null;
66 while ((temp = in.readline()) != null) {
67
68 string[] information = temp.split("[ ]+");
69 people people = new people();
70 people.setname(information[0]);
71 people.setnumber(information[1]);
72 int a = integer.parseint(information[3]);
73 people.setage(a);
74 people.setsex(information[2]);
75 for(int j = 4; j<information.length;j++) {
76 people.setplace(information[j]);
77 }
78 peoplelist.add(people);
79
80 }
81 } catch (filenotfoundexception e) {
82 system.out.println("文件未找到");
83 e.printstacktrace();
84 } catch (ioexception e) {
85 system.out.println("文件读取错误");
86 e.printstacktrace();
87 }
88 boolean istrue = true;
89 while (istrue) {
90
91 system.out.println("******************************************");
92 system.out.println(" 1.按姓名典序输出人员信息");
93 system.out.println(" 2.查询最大年龄人员信息");
94 system.out.println(" 3.查询最小年龄人员信息");
95 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");
96 system.out.println(" 5.查询人员中是否有你的同乡");
97 system.out.println(" 6.退出");
98 system.out.println("******************************************");
99 int nextint = scanner.nextint();
100 switch (nextint) {
101 case 1:
102 collections.sort(peoplelist);
103 system.out.println(peoplelist.tostring());
104 break;
105 case 2:
106 int max=0;
107 int j,k1 = 0;
108 for(int i=1;i<peoplelist.size();i++)
109 {
110 j = peoplelist.get(i).getage();
111 if(j>max)
112 {
113 max = j;
114 k1 = i;
115 }
116
117 }
118 system.out.println("年龄最大："+peoplelist.get(k1));
119 break;
120 case 3:
121 int min = 100;
122 int j1,k2 = 0;
123 for(int i=1;i<peoplelist.size();i++)
124 {
125 j1 = peoplelist.get(i).getage();
126 if(j1<min)
127 {
128 min = j1;
129 k2 = i;
130 }
131
132 }
133 system.out.println("年龄最小："+peoplelist.get(k2));
134 break;
135 case 4:
136 system.out.println("年龄：");
137 int input_age = scanner.nextint();
138 arraylist<people> plist = new arraylist<people>();
139 plist = agenear(input_age);
140 for(people people : plist) {
141 system.out.println(people.tostring());
142 }
143 break;
144 case 5:
145 system.out.println("请输入省份");
146 string find = scanner.next();
147 for (int i = 0; i <peoplelist.size(); i++)
148 {
149 string [] place = peoplelist.get(i).getplace().split("\t");
150 for(string temp : place) {
151 if(find.equals(temp)) {
152 system.out.println("你的同乡是 "+peoplelist.get(i));
153 break;
154 }
155 }
156
157 }
158 break;
159 case 6:
160 istrue = false;
161 system.out.println("byebye!");
162 break;
163 default:
164 system.out.println("输入有误");
165 }
166 }
167 }
168
169 }
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；
1 import java.io.file;
2 import java.io.fileoutputstream;
3 import java.io.printwriter;
4 import java.math.bigdecimal;
5 import java.util.scanner;
6
7
8 public class ss {
9 public static void main(string[] args) {
10
11
12 scanner in = new scanner(system.in);
13 calculator<integer> sf = new calculator<integer>();
14 file file = new file("wzt.txt");
15 if(file.exists()) {
16 system.out.println("文件已存在");
17 }
18 printwriter output = null;
19 try {
20 output = new printwriter(new fileoutputstream(file));
21 } catch (exception e) {
22 //e.printstacktrace();
23 }
24 int sum = 0;
25
26 system.out.println("计算结果保留两位小数");
27 for (int i = 1; i < 11; i++) {
28 int a = (int) math.round(math.random() * 100);
29 int b = (int) math.round(math.random() * 100);
30 int s = (int) math.round(math.random() * 3);
31
32
33 switch(s)
34 {
35 case 1:
36 system.out.println(i+": "+a+"/"+b+"=");
37 number c = in.nextdouble();
38 output.println(a+"/"+b+"="+c);
39 number g = sf.division(a, b);
40 bigdecimal division = new bigdecimal(g.doublevalue());
41 g = division.setscale(2, bigdecimal.round_half_up).doublevalue();
42 if (c.equals(g)) {
43 sum += 10;
44 system.out.println("恭喜答案正确");
45 }
46 else {
47 system.out.println("抱歉，答案错误");
48 }
49
50 break;
51
52 case 2:
53 system.out.println(i+": "+a+"*"+b+"=");
54 number c1 = in.nextdouble();
55 output.println(a+"*"+b+"="+c1);
56 number g1 = sf.mulitiplication(a, b);
57 bigdecimal mul = new bigdecimal(g1.doublevalue());
58 g1 = mul.setscale(2, bigdecimal.round_half_up).doublevalue();
59 if (c1.equals(g1) ){
60 sum += 10;
61 system.out.println("恭喜答案正确");
62 }
63 else {
64 system.out.println("抱歉，答案错误");
65 }
66 break;
67 case 3:
68 system.out.println(i+": "+a+"+"+b+"=");
69 number c2 = in.nextdouble();
70 output.println(a+"+"+b+"="+c2);
71 number g2 =sf.addition(a, b);
72 bigdecimal add = new bigdecimal(g2.doublevalue());
73 g2 = add.setscale(2, bigdecimal.round_half_up).doublevalue();
74 if (c2.equals(g2)) {
75 sum += 10;
76 system.out.println("恭喜答案正确");
77 }
78 else {
79 system.out.println("抱歉，答案错误");
80 }
81
82 break ;
83 case 4:
84 system.out.println(i+": "+a+"-"+b+"=");
85 number c3 = in.nextdouble();
86 output.println(a+"-"+b+"="+c3);
87 number g3 = sf.subtraction(a, b);
88 bigdecimal sub = new bigdecimal(g3.doublevalue());
89 g3 = sub.setscale(2, bigdecimal.round_half_up).doublevalue();
90 if (c3.equals(g3)) {
91 sum += 10;
92 system.out.println("恭喜答案正确");
93 }
94 else {
95 system.out.println("抱歉，答案错误");
96 }
97 break ;
98
99 }
100
101 }
102 system.out.println("成绩"+sum);
103 output.println("成绩:"+sum);
104 output.close();
105 in.close();
106
107 }
108 }
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。
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