课堂练习

package test;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;
  
   
public class W1 {
    static Scanner in = new Scanner(System.in);
  
    public static void main(String[] args) throws IOException {
          
        deal();
        }
          
          
          
  
      
public static void deal() throws IOException
{
    int choice = 0;
      
    while(choice != 5)
    {
        System.out.println("请输入选择");
        System.out.println("0输出字母");
        System.out.println("1输出单词");
        System.out.println("2输出前n个单词");
        System.out.println("3过滤无用词");
        System.out.println("4统计短语");
          
          
        choice = in.nextInt();
        switch (choice)
        {
        case 0 :
        {
            word();
            break;
        }
        case 1:
        {
            String filePath = "d:\\文件\\单词.txt";
            String sz=W3.readTxtFile(filePath);
            System.out.println(W2.StatList1(sz));
            break;
        }
        case 2:
        {
            String filePath = "d:\\文件\\单词.txt";
            String sz=W3.readTxtFile(filePath);
            System.out.println(W2.StatList2(sz));
            break;
        }
        case 3:
        {
            String filePath = "d:\\文件\\单词.txt";
            String sz=W3.readTxtFile(filePath);
            System.out.println(W2.StatList(sz));
            break;
        }
          
        case 4:
        {
            String filePath = "d:\\文件\\stopword.txt";
            String sz=W3.readTxtFile(filePath);
            String[] slist = sz.split("[^a-zA-Z\']+");
              
            break;
        }
        }
        }
}
      
      
      
      
  
  
public static void word() throws IOException
{
    try {
        //IO操作读取文件内容
        FileReader fr = new FileReader("d:\\文件\\单词.txt");
        BufferedReader br = new BufferedReader(fr);
        NumberFormat nf = NumberFormat.getInstance();
           
        // 设置精确到小数点后2位
   
        nf.setMaximumFractionDigits(2);
        HashMap map = new HashMap();
          
        String string =null;
        Integer count = 0;//每个字母的次数
        Integer total = 0;//总共多少个字母
          
        while ((string=br.readLine())!=null) {
            char[] ch = string.toCharArray();
              
            for (int i = 0; i < ch.length; i++) {
                if (ch[i] > 'A' && ch[i]< 'z') {
                      
                total++;
                ch[i] = Character.toLowerCase(ch[i]);
                count = map.get(ch[i]+"");
                if (count == null) {
                    count = 1;
                }else {
                    count++;
                }
                map.put(ch[i]+"", count);
            }
            }
        }
         ArrayList list = new ArrayList();
         list.addAll(map.keySet());  //将单词添加到list中
           
         //排序按照出现次数降序排列
         for(int i = 0;i < list.size();i++)
         {
               
             for(int j = 0;j < (list.size() - i-1);j++)     //list.size() - i-1因为要用到i+1要考虑是否超出范围的问题
             {
                   
                 if(map.get(list.get(j)) < map.get(list.get(j+1)))
                 {
                     String t = list.get(j);
                     list.set(j, list.get(j+1));
                     list.set( j+1, t);
                 }
             }
         }
         for(int i = 0 ; i < list.size();i++)
            {
                System.out.println(list.get(i) + ":" + map.get(list.get(i)) +"   "+ nf.format((float)(map.get(list.get(i)))*100/total) + "%");
            }
          
          
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}
  
  
  
}
 
 
package test;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Scanner;
  
  
public class W2 {
  
  
public static String StatList2(String str) {
    StringBuffer sb = new StringBuffer();
    HashMap has = new HashMap (); // 打开一个哈希表
    String[] slist = str.split("[^a-zA-Z\']+");
    for (int i = 0; i < slist.length; i++)
    {
        if (!has.containsKey(slist[i]))
        {
               has.put(slist[i], 1);
        }
        else
        {
               has.put(slist[i],has.get(slist[i])+1 );
        }
    }
    Iterator iterator = has.keySet().iterator();
    String a[]=new String[100];
    int s[]=new int[100];
    int n;
    Scanner in=new Scanner(System.in);
    System.out.println("输入前n个最常出现的单词:");
    n=in.nextInt();
    for(int i=0;i)
    {
        iterator = has.keySet().iterator();
        while(iterator.hasNext())
        {
            String word = (String) iterator.next();
            if(s[i]<has.get(word))
            {
                s[i]=has.get(word);
                a[i]=word;
            }
         }
          
         sb.append("单词：").append(a[i]).append(" 次数").append(has.get(a[i])).append("\r\n");
         has.remove(a[i]);
          
    }
         return sb.toString();
    }
  
public static String StatList1(String str) {
    StringBuffer sb = new StringBuffer();
    HashMap has = new HashMap (); // 打开一个哈希表
    String[] slist = str.split("[^a-zA-Z\']+");
    for (int i = 0; i < slist.length; i++)
    {
        if (!has.containsKey(slist[i]))
        {
               has.put(slist[i], 1);
        }
        else
        {
               has.put(slist[i],has.get(slist[i])+1 );
        }
    }
    Iterator iterator = has.keySet().iterator();
    String a[]=new String[100];
    int s[]=new int[100];
      
      
    for(int i=0;i<50;i++)
    {
        iterator = has.keySet().iterator();
        while(iterator.hasNext())
        {
            String word = (String) iterator.next();
            if(s[i]<has.get(word))
            {
                s[i]=has.get(word);
                a[i]=word;
            }
         }
          
         
         sb.append("单词：").append(a[i]).append(" 次数").append(has.get(a[i])).append("\r\n");
         has.remove(a[i]);
          
    }
         return sb.toString();
    }
  
public static String StatList(String str) {
    StringBuffer sb = new StringBuffer();
    HashMap has = new HashMap (); // 打开一个哈希表
    String[] slist = str.split("[^a-zA-Z\']+");
    for (int i = 0; i < slist.length; i++)
    {
        if (!has.containsKey(slist[i]))
        {
               has.put(slist[i], 1);
        }
        else
        {
               has.put(slist[i],has.get(slist[i])+1 );
        }
    }
    Iterator iterator = has.keySet().iterator();
    String a[]=new String[100];
    int s[]=new int[100];
    int n=15;
    int judge;
    Scanner in=new Scanner(System.in);
    System.out.println("输入前n个最常出现的单词:");
    n=in.nextInt();
    for(int i=0;i)
    {
        iterator = has.keySet().iterator();
        while(iterator.hasNext())
        {
            String word = (String) iterator.next();
            if(s[i]<has.get(word))
            {
                s[i]=has.get(word);
                a[i]=word;
            }
         }
        judge=woor(a[i]);
        if(judge==1)
        {
            n++;
            has.remove(a[i]);
        }
        else
        {
         sb.append("单词：").append(a[i]).append(" 次数").append(has.get(a[i])).append("\r\n");
         has.remove(a[i]);
        }
    }
         return sb.toString();
    }
    public static void main(String[] args)
    {
        File file = new File("d:\\文件");
//      // TODO Auto-generated method stub
//      ArrayList fil=getFiles("d:\\文件");//目录下的文件
        ArrayList fil=getDirectory(file);//目录下的文件和子目录里的文件
        for(int i=0;i)
        {
        String filePath = fil.get(i);
        //String filePath = "d:\\文件\\单词.txt";
        String sz=W3.readTxtFile(filePath);
        String ltxt=null;
        System.out.println(ltxt=StatList(sz));
        try {
        W3.daochu(ltxt);
        } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        }
        }
          
    }
      
    public static int woor(String a)
    {
        int n=0;
        String filePath = "d:\\文件\\stopword.txt";
        String sz=W3.readTxtFile(filePath);
        String[] slist = sz.split("[^a-zA-Z\']+");
        for(int i=0;i)
        {
            if(slist[i].equals(a))
            {
                n=1;
            }
        }
        return n;
    }
      
    public static ArrayList getFiles(String path) {
        ArrayList files = new ArrayList();
        File file = new File(path);
        File[] tempList = file.listFiles();
        for (int i = 0; i < tempList.length; i++) {
            if (tempList[i].isFile()) {
                files.add(tempList[i].toString());
            }
            if (tempList[i].isDirectory()) {
            }
        }
        return files;
    }
      
    private static ArrayList getDirectory(File file) {
        ArrayList files = new ArrayList();
        ArrayList files1 = new ArrayList();
        //获取该目录下的文件列表
        File flist[] = file.listFiles();
        for (File f : flist) {
            if (f.isDirectory()) {
                // 如果f是一个目录
                files1=getFiles(f.getAbsolutePath());
                files.addAll(files1);
                 
                getDirectory(f);
            } else {
                //如果f是一个文件
                files.add(f.getAbsolutePath());
            }
        }
        return files;
    }
  
  
}
 
 
package test;
  
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
//import java.io.Reader;
//从文本文档中读入
public class W3 {
    public static String readTxtFile(String filePath){
        try {
            String encoding="GBK";
            File file=new File(filePath);
            if(file.isFile() && file.exists()){ //判断文件是否存在
            InputStreamReader read = new InputStreamReader(
            new FileInputStream(file),encoding);//考虑到编码格式
            BufferedReader bufferedReader = new BufferedReader(read);
            String lineTxt = null;
            String lineText="";
            while((lineTxt = bufferedReader.readLine()) != null)
                {
                lineText+=(lineTxt);
                }
            read.close();
            return lineText;
            }
            else
                {
                System.out.println("找不到指定的文件");
                }
            } catch (Exception e) {
            System.out.println("读取文件内容出错");
            e.printStackTrace();
            }
            return null;
        }
        public static void daochu(String a) throws IOException
        {
            File file=new File("d:\\文件\\c.txt");
            FileOutputStream fos=new FileOutputStream(file);
            OutputStreamWriter osw = new OutputStreamWriter(fos,"UTF-8");
            osw.append(a);
            osw.close();
            fos.close();
        }
}