利用java内置库的HashMap统计字符串中单词出现的个数问题

没什么好说的，我就直接把代码放上面吧：

package com.anduo.map;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

public class HashMapTest2 {
	public static void main(String[] args) {
		String s = "abbaadfdgdeiivnielo";

		HashMap<Character, Integer> map = new HashMap<Character, Integer>();

		char c;

		for (int i = 0; i < s.length(); i++) {
			c = s.charAt(i);
			if (map.get(c) == null) {
				map.put(c, 1);
			} else {
				Integer in = map.get(c);
				map.put(c, in.intValue() + 1);
			}
		}

		Set<Character> set = map.keySet();
		for (Character ch : set) {
			System.out.println(ch + " " + map.get(ch));
		}

		System.out.println("----------------------");
//另外一种访问方式

		Set<Entry<Character, Integer>> set1 = map.entrySet();
		for (Iterator<Entry<Character, Integer>> iterator = set1.iterator(); iterator
				.hasNext();) {
			Map.Entry<Character, Integer> entry = (Map.Entry<Character, Integer>) iterator
					.next();
			Character ch = entry.getKey();
			Integer integer = entry.getValue();
			System.out.println(ch + "  " + integer);

		}

	}
}