作业4.2

结对对象：严瑞   微博地址：http://www.cnblogs.com/yanrui666/p/5303941.html   github：https://github.com/yanrui666/yanrui123/blob/master/作业4    贡献比例：50%/50%

读取小文本文件A_Tale_of_Two_Cities.txt 或者 大文本文件Gone_with_the_wind.txt，统计某一指定单词在该文本文件中出现的频率。

• 命令行格式： 提示符> Myapp.exe -f filename.txt -w word （PS：C++ 程序，Java 程序输出方式类似）
• 解释：
  • 选项 -f 表示打开某一文件（filename.txt）
  • 选项 -w 表示统计其后单词（word）在打开的文件（filename.txt）中的频率。

java输入和特定单词频率统计统计：

Scanner s=new Scanner(System.in);

System.out.println("请输入要查找的单词： ");

String str = s.next();

int count=0;

for(int j=0;j<words.length;j++)

{if(str.equals(words[j]))  count++;}

System.out.println("所查单词频率为:"+count);

源程序：

import java.util.*;

import java.io.*;

public class WordsRate

{

    public static void main(String[] args) throws Exception

   {

       BufferedReader infile = new BufferedReader(new FileReader("D:\A_Tale_of_Two_Cities.txt"));

       String string;

       String file = null;

       while ((string = infile.readLine()) != null) { file += string; }

       file = file.toLowerCase();

       file = file.replaceAll("[^A-Za-z]", " ");

       file = file.replaceAll("\s+", " ");

       String words[];

       words = file.split("\s+");

       Map<String, Integer> hashMap = new HashMap<String, Integer>();

       for (int i = 0; i < words.length; i++)

       {

            String key = words[i];

            if (hashMap.get(key) != null)

            {

                 int value = ((Integer) hashMap.get(key)).intValue();

                 value++;

                 hashMap.put(key, new Integer(value));

             }

             else { hashMap.put(key, new Integer(1)); }

       }

       Map<String, Object> treeMap = new TreeMap<String, Object>(hashMap);

       Map<String, Object> treeMap1 = new TreeMap<String, Object>(hashMap);

       BufferedWriter bw = new BufferedWriter(new FileWriter("result1.txt"));

       Iterator iter = treeMap.entrySet().iterator();

       String ss1[]=new String[treeMap.size()];;

       int ss2[]=new int[treeMap.size()];

       int i=0;

       while (iter.hasNext())

       {

            Map.Entry entry = (Map.Entry) iter.next();

            int val = (Integer)entry.getValue();

            String key =(String) entry.getKey();

            ss1[i]=key;

            ss2[i]=val;

            i++;

       }

       int sValue=0;

       String sKey="";

       for(int j=0;j<ss2.length;j++)

       {

            for(int k=0;k<i;k++)

            {

                  if(ss2[j]>ss2[k])

                  {

                        sValue=ss2[j];

                        sKey=ss1[j];

                        ss2[j]=ss2[k];

                        ss1[j]=ss1[k];

                        ss2[k]=sValue;

                        ss1[k]=sKey;

                  }

             }

        }

        int[] strLengths = new int[ss2.length];

        for(int j=0 ;j<ss2.length; j++)

        {  

             strLengths[j] = ss1[j].length();

        }

        Scanner s=new Scanner(System.in);

        System.out.println("请输入要查找的单词： ");

        String str = s.next();

        int count=0;    

        for(int j=0;j<words.length;j++)

        { 

             if(str.equals(words[j]))  count++;

         }

        System.out.println("所查单词频率为:"+count);

        for(int j=0;j<ss2.length;j++)

        {

              if(strLengths[j]>=4)  System.out.println(ss1[j]+"="+ss2[j]);

              bw.write(ss1[j]+"="+ss2[j]);

              bw.newLine(); bw.flush();

        }

    }

}

运行结果：

心得：经过了第一次的学习这次用java更熟悉了。