课堂练习（续）

源程序：

Text_2.java

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Scanner;
public class Text_2 {
static int N=5;

public static String StatList(String str) {
    StringBuffer sb = new StringBuffer();
    HashMap<String ,Integer> has = new HashMap<String ,Integer> (); // 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<String> iterator = has.keySet().iterator();
    String a[]=new String[100];
    int s[]=new int[100];
    int judge;
    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<n;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) 
    {
        display();
        // TODO Auto-generated method stub
//        ArrayList<String> fil=getFiles("a");//目录下的文件
//        ArrayList<String> fil=getDirectory(file);//目录下的文件和子目录里的文件
//        for(int i=0;i<fil.size();i++)
//        {
//        String filePath = fil.get(i);
//        String sz=writeFromFile.readTxtFile(filePath);
//        zimu(filePath);
//        String ltxt=null;
//        System.out.println(ltxt=StatList(sz)); 
//        try {
//        writeFromFile.daochu(ltxt);
//        } catch (IOException e) {
//        // TODO Auto-generated catch block
//        e.printStackTrace();
//        }
//        }
    }
    public static int woor(String a)
    {
        int n=0;
        File ctoFile = new File("stopword.txt");
        InputStreamReader rdCto;
        try {
            rdCto = new InputStreamReader(new FileInputStream(ctoFile));
            BufferedReader bfReader = new BufferedReader(rdCto);
            String txtline = null;
            try {
                while ((txtline = bfReader.readLine()) != null) 
                {
                    if(txtline.equals(a))
                        {
                            n=1;
                        }
                }
                bfReader.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
             
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        
        
        
//        int n=0;
//        String[] biao= {"a","the","an","it","and","this","I","t","s"};
//        for(int i=0;i<biao.length;i++)
//        {
//            if(biao[i].equals(a))
//            {
//                n=1;
//            }
//        }
        return n;
    }
    public static ArrayList<String> getFiles(String path) {
        ArrayList<String> files = new ArrayList<String>();
        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<String> getDirectory(File file) {
        ArrayList<String> files = new ArrayList<String>();
        ArrayList<String> files1 = new ArrayList<String>();
        //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;
    }
    public static void zimu(String path)
    {
        try {
            //IO操作读取文件内容
            FileReader fr = new FileReader(path);
            BufferedReader br = new BufferedReader(fr);
            DecimalFormat df = new DecimalFormat("#.00");
            HashMap<String, Integer> map = new HashMap<String, Integer>();
            
            String string =null;
            Integer count = 0;//每个字母的次数
            Integer total = 0;//总共多少个字母
            
            try {
                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);
                    }
                    }
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
             ArrayList<String> list = new ArrayList<String>();
             list.addAll(map.keySet());  //将单词添加到list中
             NumberFormat numberFormat = NumberFormat.getInstance();
             
            // 设置精确到小数点后2位
     
            numberFormat.setMaximumFractionDigits(2);
             
             //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)) +"   "+ df.format(((float)map.get(list.get(i)))*100/total) + "%");
                }
            
            
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public static String StatList1(String str) {
        StringBuffer sb = new StringBuffer();
        HashMap<String ,Integer> has = new HashMap<String ,Integer> (); // 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<String> iterator = has.keySet().iterator();
        String a[]=new String[100];
        int s[]=new int[100];
        int judge;
        int n=20;
        for(int i=0;i<n;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 String StatList2(String str) {
        StringBuffer sb = new StringBuffer();
        HashMap<String ,Integer> has = new HashMap<String ,Integer> (); // 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<String> iterator = has.keySet().iterator();
        String a[]=new String[2000];
        int s[]=new int[2000];
        int judge;
        int n=1000;
        String duanyu="";
        for(int i=0;i<n;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]);
                System.out.println(duanyu);
                duanyu="";
            }
            else
            {
                duanyu=duanyu+" "+a[i];
                has.remove(a[i]);
            }
        }
             return sb.toString();
        }
    public static void display()
    {
        File file = new File("a");
        int n=0;
        Scanner in=new Scanner(System.in);
        while(n!=5)
        {
        System.out.println("请选择命令");
        System.out.println("5退出");
        System.out.println("1字母");
        System.out.println("2单词");
        System.out.println("3前n个单词");
        System.out.println("4短语");
        n=in.nextInt();
        if(n==1)
        {
            zimu("a.txt");
            
        }
        if(n==2)
        {
            String sz=writeFromFile.readTxtFile("a.txt");
            String ltxt=null;
            System.out.println(ltxt=StatList1(sz)); 
            try {
            writeFromFile.daochu(ltxt);
            } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            }
        }
        if(n==3)
        {
            String sz=writeFromFile.readTxtFile("a.txt");
            String ltxt=null;
            System.out.println(ltxt=StatList(sz)); 
            try {
            writeFromFile.daochu(ltxt);
            } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            }
        }
        if(n==4)
        {
            String sz=writeFromFile.readTxtFile("a.txt");
            String ltxt=null;
            System.out.println(ltxt=StatList2(sz)); 
            try {
            writeFromFile.daochu(ltxt);
            } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            }
        }
        }
    }
    


}

writeFromFile.java

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 writeFromFile {
    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("b.txt");
        FileOutputStream fos=new FileOutputStream(file);
        OutputStreamWriter osw = new OutputStreamWriter(fos,"UTF-8");
        osw.append(a);
        osw.close();
        fos.close();
    }
}

实验截图：

实验总结：

这次的实验在上次的基础上，要把上次的功能写成函数，分别进行调用，因为上次的实验我已经将功能写成函数，所以在这次的实验中写了一个界面，对函数进行了分别调用