统计某字符串中每个字符出现的次数

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		System.out.println("Input a string:");
		String _str = s.nextLine(); // 输入要统计的字符串
		Map<Character, Integer> map = countChar(_str);
		System.out.println(map);
	}

	static Map<Character, Integer> countChar(String s) {
		Map<Character, Integer> map = new HashMap<Character, Integer>();
		char c = '\0';
		for (int i = 0; i < s.length(); i++) {
			c = s.charAt(i);
			if (map.containsKey(Character.valueOf(c))) // 如果Map存在该k值则返回 true。
				map.put(Character.valueOf(c), Integer.valueOf(map.get(
						Character.valueOf(c)).intValue() + 1));
			else
				map.put(Character.valueOf(c), Integer.valueOf(1));
		}
		return map;
	}