统计单词出现的次数，Java实现

import java.util.*;

public class CountWords {

    public static void main(String[] args) {
        String text = "Good morning.Have a good class."+
                      "Have a good visit.Have fun";
        Map<String,Integer> map = new TreeMap<>();
        
        String[] words = text.split("[ \n\t\r.,;!]");
        for(int i = 0; i < words.length;i++) {
            String key = words[i].toLowerCase();
            
            if(key.length() > 0) {
                if(!map.containsKey(key)) {
                    map.put(key, 1);
                }
                else {//如果不是第一次出现，就把value值++，那么value值是多少就是出现了几次
                    int value = map.get(key);
                    value++;
                    map.put(key, value);
                }
            }
        }
        
        Set<Map.Entry<String, Integer>> entrySet = map.entrySet();
        
        for(Map.Entry<String, Integer> entry:entrySet)
            System.out.println(entry.getKey()+"\t"+entry.getValue());
        
    }

}