Java实现统计字符串出现的次数

public class StrCount {

     public static void main(String[] args) {

         //健盘录入一个字符串

         Scanner sc = new Scanner(System.in);

         System.out.println( "清输入一串字符串:" );

         String line = sc.nextLine();

         //创建HashMap集合,键是Character, 值是Integer

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

         //遍历字符申，得到每一个字符

         for ( int i = 0 ; i < line.length(); i++) {

             char key = line.charAt(i);

             //拿得到的每一个字符作为键到HashMap集合中去找对应的值，看其返回值

             Integer value = map.get(key);

             if (value == null ) {

                 //如果返回值是null:说明该字符在HashMap集合中不存在,就把该字符作为键，1作为值存储

                 map.put(key, 1 );

             } else {

                 //如果返回值不是ull:说明该字符在HashMap集合中存在,把该值加1,然后重新存储该字符和对成的值

                 value++;

                 map.put(key, value);

             }

         }

         //遍历HashMap集合,得到键和值，按照要求进行拼接

         StringBuilder sb = new StringBuilder();

         Set<Character> keySet = map.keySet();

         for (Character key : keySet) {

             Integer value = map.get(key);

             sb.append(key).append( "(" ).append(value).append( ")" );

         }

         //输出结果

         String result = sb.toString();

         System.out.println(result);

     }

}

//遍历HashMap集合,得到键和值，按照要求进行拼接

         Set<Character> keySet = map.keySet();

         for (Character key : keySet) {

             Integer value = map.get(key);

             //输出结果

             System.out.print(key + "(" + value + ")" );

         }