课堂测试2

package Statistics;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class FileOutput1 {

    public static void main(String[] args)throws IOException//扔掉很重要
    {

         File file = new File("Harry Potter and the Sorcerer‘s Stone.txt");
         FileReader fr = new FileReader(file);
         BufferedReader br = new BufferedReader(fr);//构造一个BufferedReader类来读取文件    
         StringBuffer sb = new StringBuffer();
         String line =null;
         while ((line=br.readLine())!=null){
            sb.append(line);//将读取出的字符追加到stringbuffer中
        }     
        fr.close();
       // 关闭读入流
             String str = sb.toString().toLowerCase(); // 将stringBuffer转为字符并转换为小写
             String[] words = str.split("[^(a-zA-Z)]+");  // 非单词的字符来分割，得到所有单词
             Map<String ,Integer> map = new HashMap<String, Integer>() ;
             for(String word :words){
                 if(map.get(word)==null){  // 若不存在说明是第一次，则加入到map,出现次数为1
                     map.put(word,1);
                 }else{
                     map.put(word,map.get(word)+1);  // 若存在，次数累加1
                 }
             }
             // 排序
            List<Map.Entry<String ,Integer>> list = new ArrayList<Map.Entry<String,Integer>>(map.entrySet());
             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) {
                  int i=left.getValue()-right.getValue();
                     if(i==0) {
                      return (right.getKey().compareTo(left.getKey()));
                     }
                     return (left.getValue().compareTo(right.getValue()));
                 }
             };
             // 集合默认升序
             Collections.sort(list,comparator);
             int n=list.size();
             System.out.println("一共有"+n+"种单词");
             System.out.println("请输入你要排序前几个单词：");
             Scanner s=new Scanner(System.in);
             n=s.nextInt();
             for(int i=0;i<n;i++){// 由高到低输出
                 System.out.println(list.get(list.size()-i-1).getKey() +":"+list.get(list.size()-i-1).getValue());
             }
    }
}