package com.test.string; import java.io.BufferedReader; 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.Map.Entry; import java.util.regex.Matcher; import java.util.regex.Pattern; public class TesWordCount { /**解题思路 * 1.先去取文件的问内容 * 2.对读取文件中的内容进行正则匹配【a-zA-Z】 * 3.用Map保存 单词 和出现的次数 * 4.自定义Comparator排序 * 5.把map中内容放到list中 * 6.对list进行Collections.sort() 进行自定义排序 * 7。输出排序后的内容 * * * * * * @param args * @throws IOException */ public static void main(String[] args) throws IOException { // TODO Auto-generated method stub @SuppressWarnings("resource") BufferedReader buffer=new BufferedReader(new FileReader("d:/c.txt")); StringBuffer sb=new StringBuffer(); String str=null; while((str=buffer.readLine())!=null){ sb.append(str); } buffer.close(); Pattern pattern=Pattern.compile("[a-zA-Z]+"); Matcher matcher=pattern.matcher(sb.toString()); Map<String,Integer> map=new HashMap<String,Integer>(); String word=""; int count; while(matcher.find()){ word=matcher.group(); //System.out.println("sr="+word); if(map.containsKey(word)){ count=map.get(word); map.put(word, count+1); }else{ map.put(word, 1); } } List<Map.Entry<String,Integer>> list=new ArrayList<Map.Entry<String,Integer>>(map.entrySet()); Collections.sort(list,new MyComparable()); int last=list.size()-1; for(int i=last;i>last-5;i--){ System.out.println("key="+list.get(i).getKey()+" value="+list.get(i).getValue()); } } } class MyComparable implements Comparator<Map.Entry<String,Integer>>{ @Override public int compare(Entry<String, Integer> o1, Entry<String, Integer> o2) { // TODO Auto-generated method stub return o1.getValue().compareTo(o2.getValue()); } }
一道Java面试题 读取一篇英文文章,输出其中出现单词的次数最多的5个,写java函数
原文:http://blog.csdn.net/renshuang2788445011/article/details/19167775