写一个程序，用于分析一个字符串中各个单词出现的频率，并将单词和它出现的频率输出显示。（单词之间用空格隔开，如“Hello World My First Unit Test”）

import java.io.BufferedReader;  
import java.io.FileReader;  
import java.io.FileNotFoundException;  
import java.io.IOException;  
import java.util.*;  
    
public class first{  
     public static void main(String[] args)   
     {  
         try {  
             BufferedReader br = new BufferedReader(new FileReader("D:\\test.txt"));//新建缓存区读取为所需统计文件的读取  
               
             StringBuffer mp= new StringBuffer(); 
             String s;  
             ;  
          while (( s=br.readLine())!= null) {  
                 mp.append(s); 
             }  
             Map<String,Integer>   map = new HashMap<String, Integer>();//运用哈希排序的方法进行排序  
             StringTokenizer st = new StringTokenizer(mp.toString(),",.! \n");//分割字符串  
           //用来测试是否有此标记生成器的字符串可以有更多的标记。并把分割好的单词保存在letter字符串中。  
             while (st.hasMoreTokens()) {  
                 String letter = st.nextToken();  
                 int count;  
                 if (map.get(letter) == null) {  
                     count = 1;//表明了没有进行分割。  
                 } else {  
                     count = map.get(letter).intValue() + 1;  
                 }  
                 map.put(letter,count);  
             }  
             Set<WordEntity> set = new TreeSet<WordEntity>();  
             for (String key : map.keySet()) {  
                 set.add(new WordEntity(key,map.get(key)));  
             }  
              
               
             
             int count = 1;  
             for (Iterator<WordEntity> it = set.iterator(); it.hasNext(); ) {  
                 WordEntity w = it.next();

                if (count == 10)// 当输出10个后跳出循环  
                     break;  
                 count++;  
             }  
                 
         } catch (FileNotFoundException e) {  
             System.out.println("文件未找到~！");//异常处理  
         } catch (IOException e) {  
             System.out.println("文件读异常~！");//异常处理  
         }  
     }

    public void countWord(String string) {
        // TODO Auto-generated method stub
        
    }  
 }  
class WordEntity implements Comparable<WordEntity> {  
        private String key;  
        private Integer count;  
        public WordEntity (String key, Integer count) {  
            this.key = key;  
            this.count = count;  
        }  
        public int compareTo(WordEntity o) {  
            int cmp = count.intValue() - o.count.intValue();  
            return (cmp == 0 ? key.compareTo(o.key) : -cmp);  
            //只需在这儿加一个负号就可以决定是升序还是降序排列  -cmp降序排列，cmp升序排列  
            //因为TreeSet会调用WorkForMap的compareTo方法来决定自己的排序  
        }  
       
       
        public String toString() {  
            return key + " 出现的次数为：" + count;  
        }  
       
       public String getKey() {  
            return key;  
        }  
       
       public Integer getCount() {  
            return count;  
        }  
    }  
       
import static org.junit.Assert.*;
import org.junit.Test;

public class TestTest {

@Test
public void testCountWord() {
first demo = new first();
demo.countWord("Hello World My First Unit Test");
}

}