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”）；

package cn.lin.Test;

 

import java.first.HashMap;

import java.first.Map;

 

import org.junit.Test;

 

 

public class Test{ 

   @Test

    public void index() { 

      String strWords = "aab abc cca aaa";

     

      String[] words_Array = strWords.split(" ");

      Map<String,Integer> words_Map=new HashMap<String, Integer>();

      int arrLength = words_Array.length;

      for(int i=0;i<arrLength;i++){

         if(!words_Map.containsKey(words_Array[i])){

            words_Map.put(words_Array[i], 1);

            System.out.println(words_Array[i]);

            System.out.println("出现");

            System.out.println(words_Map.put(words_Array[i], 1));

            System.out.println("次");

           

         }else{

            int currentNum = words_Map.get(words_Array[i])+1;

            words_Map.remove(words_Array[i]);

            words_Map.put(words_Array[i], currentNum);

            System.out.println(words_Array[i]);

            System.out.println("出现");

            System.out.println(words_Map.put(words_Array[i], currentNum));

            System.out.println("次");

         }

        

      }

   }

 

 

}