题目：
根据 coreJava.txt 文件：
- 提炼出 Question 类
- 解析文件（一个函数），要求：
- 把同个等级的题目，放入同一个 ArrayList 集合；
- 把等级作为 key，把 ArrayList 集合作为 value，放入 Map 集合；
- 出一套考题，每个等级一道题目（随机选出 Random）写成一个函数
部分 coreJava.txt 内容如下：
@answer=2/3,score=5,level=5
指出下面语句没有编译错误的是:
long n = 999999999999;
int n = 999999999999L;
long n = 999999999999L;
double n = 999999999999;
@answer=1/2,score=5,level=4
下列关于数组的声明错误的是:
int[] arry = new int[100];
int[3] arry = {1,2,3};
int[] arry = new int[]{1,2,3};
int[][] arry = new int[3][];
@answer=0/1/2,score=5,level=3
语句System.out.println(1+2+"java"+3+4)输出的结果是:
3java34
12java34
3java7
12java7
@answer=1,score=5,level=6
Java语言中int类型标示整数的最大范围是:
-2147483647~ 2147483647
<T>-2147483648 ~2147483647
-32767~32767
-32768~32767
@answer=1,score=5,level=7
Java语言中字符串“学Java”所占的内存空间是:
6个字节
7个字节
10个字节
11个字节
@answer=1,score=5,level=8
对JDK描述错误的是:
运行Java程序只要有JRE环境就可以，不一定需要全部JDK的功能
JDK中包括JVM、核心类库、Java开发工具(java，javac)等
JDK本身也是平台无关的，不同的操作系统安装的JDK是一样的
JDK的全称是 Java Development Kit
答案：
1. Question.java
作用：提炼出 Question 类
package homework4_27;
import java.util.ArrayList;
public class Question {
private int score;
private int level;
private String answer;
private String description;
private ArrayList<String> options;
public Question() {
this.options = new ArrayList<String>();
}
public Question(int score, int level, String answer, String description) {
super();
this.score = score;
this.level = level;
this.answer = answer;
this.description = description;
this.options = new ArrayList<String>();
}
public int getScore() {
return score;
}
public void setScore(int score) {
this.score = score;
}
public int getLevel() {
return level;
}
public void setLevel(int level) {
this.level = level;
}
public String getAnswer() {
return answer;
}
public void setAnswer(String answer) {
this.answer = answer;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public ArrayList<String> getoptions() {
return options;
}
public void addOption(String op) {
options.add(op);
}
@Override
public String toString() {
return "Question [score=" + score + ", level=" + level + ", answer=" + answer + ", description=" + description
+ ", options=" + options + "]";
}
public void showQuestion() {
System.out.println("Question: " + description);
System.out.println("Options: ");
for(String op : options) {
System.out.println(op);
}
System.out.println("Answer: " + answer);
System.out.println("Score: " + score);
}
}
2. homework2.java
作用：
- 解析文件：
- 把同个等级的题目，放入同一个 ArrayList 集合；
- 把等级作为 key，把 ArrayList 集合作为 value，放入 Map 集合；
package homework4_27;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
// 解析 v2.0，将所有解析后的问题放入单一一个 ArrayList 中
public class homework2 {
public static void main(String[] args) {
// 按 level 存入的问题集
HashMap<Integer, ArrayList<Question> > questWithLevel = new HashMap<Integer, ArrayList<Question> >();
try {
BufferedReader br =
new BufferedReader(
new InputStreamReader(
new FileInputStream("/Users/upcautolang/Documents/corejava.txt")));
String str = null;
Question question = null;
int extraLineNum = 0;
while((str = br.readLine()) != null){
// 包含 @，则可以分析问题的学分、答案、等级
if(str.contains("@")) {
// 将当前非空的 question 传入 questWithLevel 的 Map 集合
if(question != null) {
int key = question.getLevel();
ArrayList<Question> tmpList = new ArrayList<Question>();
if(questWithLevel.containsKey(key)) {
tmpList = questWithLevel.get(key);
}
else {
tmpList = new ArrayList<Question>();
}
tmpList.add(question);
questWithLevel.put(key, tmpList);
}
question = new Question();
// 切分信息
// 例：@answer=2/3,score=5,level=5
String[] infos = str.split("[@,][a-z]+=");
// 设置答案，成绩，等级
question.setAnswer(infos[1]);
question.setScore(Integer.parseInt(infos[2]));
question.setLevel(Integer.parseInt(infos[3]));
extraLineNum = 0;
}
else {
if(extraLineNum == 0) {
question.setDescription(str);
extraLineNum = 1;
}
else {
question.addOption(str);
extraLineNum++;
}
}
}
// 测试打印
for(int level : questWithLevel.keySet()) {
System.out.println("================================");
System.out.println("Level " + level + " Question Set:");
System.out.println("---------");
ArrayList<Question> questionList = questWithLevel.get(level);
for(Question quest : questionList) {
System.out.println(quest);
}
}
} catch (IOException e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
3. homework3.java
作用：出一套考题，每个等级一道题目（随机选出 Random）写成一个函数
package homework4_27;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Random;
// 解析 v2.0，将所有解析后的问题放入单一一个 ArrayList 中
public class homework3 {
public static void main(String[] args) {
// 按 level 存入的问题集
HashMap<Integer, ArrayList<Question> > questWithLevel = new HashMap<Integer, ArrayList<Question> >();
try {
BufferedReader br =
new BufferedReader(
new InputStreamReader(
new FileInputStream("/Users/upcautolang/Documents/corejava.txt")));
String str = null;
Question question = null;
int extraLineNum = 0;
while((str = br.readLine())!=null){
// 包含 @，则可以分析问题的学分、答案、等级
if(str.contains("@")) {
// 将当前非空的 question 传入 questWithLevel 的 Map 集合
if(question != null) {
int key = question.getLevel();
ArrayList<Question> tmpList = new ArrayList<Question>();
if(questWithLevel.containsKey(key)) {
tmpList = questWithLevel.get(key);
}
else {
tmpList = new ArrayList<Question>();
}
tmpList.add(question);
questWithLevel.put(key, tmpList);
}
question = new Question();
// 切分信息
// 例：@answer=2/3,score=5,level=5
String[] infos = str.split("[@,][a-z]+=");
// 设置答案，成绩，等级
question.setAnswer(infos[1]);
question.setScore(Integer.parseInt(infos[2]));
question.setLevel(Integer.parseInt(infos[3]));
extraLineNum = 0;
}
else {
if(extraLineNum == 0) {
question.setDescription(str);
extraLineNum = 1;
}
else {
question.addOption(str);
extraLineNum++;
}
}
}
// 随机出题
System.out.println("=========================");
System.out.println(" 琦少的随机考试");
System.out.println("=========================");
for(int level : questWithLevel.keySet()) {
System.out.println("------- Level " + level + " --------");
ArrayList<Question> questionList = questWithLevel.get(level);
// int randomNumber = (int) Math.round(Math.random() * (questionList.size()-1));
int randomNumber = new Random().nextInt(questionList.size());
questionList.get(randomNumber).showQuestion();
}
} catch (IOException e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
