《软件测试》课程-第二次作业

题目一：写一个程序，用于分析一个字符串中各个单词出现的频率，并将单词和它出现的频率输出显示。

package test1;

  import java.io.BufferedReader;
  import java.io.FileReader;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
 
  public class WordCount {
     public void run() throws Exception {
         
         long time1 = System.currentTimeMillis();
         BufferedReader reader = new BufferedReader(new FileReader(
                "D:\wordtest.txt"));
         StringBuffer buffer = new StringBuffer();
         String line = null;
        while ((line = reader.readLine()) != null) {
            buffer.append(line);
        }
        reader.close();
        Pattern expression = Pattern.compile("[a-zA-Z]+");// 定义正则表达式匹配单词
        String string = buffer.toString();
         Matcher matcher = expression.matcher(string);//
        Map<String, Integer> map = new TreeMap<String, Integer>();
        String word = "";
         int times = 0;
        while (matcher.find()) {// 是否匹配单词
             word = matcher.group();// 得到一个单词-树映射的键
            if (map.containsKey(word)) {// 如果包含该键，单词出现过
               times = map.get(word);// 得到单词出现的次数
                 map.put(word, times + 1);
            } else {
                map.put(word, 1);// 否则单词第一次出现，添加到映射中
            }
         }
        /*
          * 核心：如何按照TreeMap 的value排序而不是key排序.将Map.Entry放在集合里，重写比较器，在用
         * Collections.sort(list, comparator);进行排序
         */

        List<Map.Entry<String, Integer>> list = new ArrayList<Map.Entry<String, Integer>>(
                map.entrySet());
        /*
         * 重写比较器
          * 取出单词个数（value）比较
          */
        Comparator<Map.Entry<String, Integer>> comparator = new Comparator<Map.Entry<String, Integer>>() {
             public int compare(Map.Entry<String, Integer> left,
                     Map.Entry<String, Integer> right) {
                return (left.getValue()).compareTo(right.getValue());
            }
        };
         Collections.sort(list, comparator);// 排序
        // 打印
         int last = list.size() - 1;
         try{
            for (int i = last; i > last-10; i--) {
                String key = list.get(i).getKey();
                Integer value = list.get(i).getValue();
                System.out.print("Top"+i+"  : ");
                System.out.println(key + " " + value);
            }
         }catch(Exception e){
             //System.out.println("");
         }
         long time2 = System.currentTimeMillis();
         System.out.print("耗时：");
         System.out.println(time2 - time1+"ms");
     }
 }

}

package test1;

import static org.junit.Assert.*;

import org.junit.Test;

public class WordCountTest {

    @Test
    public void test() throws Exception {
        WordCount wordtest=new WordCount();
        wordtest.run();
        
    }

}

题目二：把一个英语句子中的单词次序颠倒后输出

package test2;

import java.util.Scanner;
public class StringDemo {

public void run(){
Scanner in=new Scanner(System.in);
while(true){
String s=in.nextLine();
if(s.equalsIgnoreCase("quit")){
System.exit(0);
}
String[] ss=s.split("\s+");
StringBuffer sb=new StringBuffer();
for (int i=ss.length-1;i>=0;i--){
sb.append(ss[i]+" ");
}
System.out.println(sb);
}
}
}
package test2;

import static org.junit.Assert.*;

import org.junit.Test;

public class StringDemoTest {

    @Test
    public void test() {
        StringDemo stringdemo=new StringDemo();
        stringdemo.run();
    }

}