程序统计字符串中每个单词出现的次数。

import java.util.HashMap;

import java.util.Map;
/*来自 
 N o w  J a v a  . c o m*/

import java.util.Set;

import java.util.TreeSet;


public class Main {

  public static void main(String[] args) {

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


    createMap(myMap); // create map based on user input

    displayMap(myMap); // display map content

  }


  private static void createMap(Map<String, Integer> map) {

    String input = "this is a test this is a test";


    String[] tokens = input.split(" ");


    // processing input text

    for (String token : tokens) {/*时 代 J     a    v  a - nowjava.com*/

      String word = token.toLowerCase(); // get lowercase word


      // if the map contains the word

      if (map.containsKey(word)) // is word in map

      {

        int count = map.get(word); // get current count

        map.put(word, count + 1); // increment count

      } else

        map.put(word, 1); // add new word with a count of 1 to map

    }

  }


  // display map content

  private static void displayMap(Map<String, Integer> map) {

    Set<String> keys = map.keySet(); // get keys


    // sort keys

    TreeSet<String> sortedKeys = new TreeSet<>(keys);


    System.out.pr