应用MAP来统计字符出现的次数

/** * 使用HashMap的Key唯一来计算字符串中字母的重复次数 *  * @param str需要计算的字符串 *  * @return字符串的统计信息 */public Map<String, Integer> getStrInfo(String str) {Map<String, Integer> map = new HashMap<String, Integer>();char[] c = str.toCharArray();for (int i = 0; i < c.length; i++) {if (!map.containsKey(c[i] + "")) {map.put(c[i] + "", 1);} else {map.put(c[i] + "", map.get(c[i] + "") + 1);}}return map;}/** *  * @param args */public static void main(String[] args) {String str = "pfahdfnal;jfjlfandfsdhfajfopjsdlfnaihf34h3wq4kne,foahf9auf8-a9";Map<String, Integer> map = new Test().getStrInfo(str);System.out.println("字符串中包含了"+map.size()+"个不同的字;");Iterator<String> it = map.keySet().iterator();while (it.hasNext()) {String key = it.next();System.out.println(key + " = " + map.get(key));}}