取出一个字符串中字母出现的次数。如：字符串：”abcdekka27qoq”，输出格式为：a(2)b(1)k(2)…

取出一个字符串中字母出现的次数。如：字符串：”abcdekka27qoq”，输出格式为：a(2)b(1)k(2)…

import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeMap;

public class 获取字母出现的次数 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.nextLine();

        char[] ch = s.toCharArray();
        Map<Character,Integer> map = new TreeMap();

        for (int i = 0; i < ch.length; i++) {
            char key = ch[i];
            int value = 1;
            if (map.get(key) != null) {
                value = value + map.get(key);
            }
            map.put(key,value);
        }

        //映射关系的类型是Map.Entry类型，它是Map接口的内部接口
        Set mappings = map.entrySet();
        for (Object mapping :mappings) {
            Map.Entry entry = (Map.Entry) mapping;
            System.out.print(entry.getKey() + "{" + entry.getValue() + "}" + " ");
        }
    }
}

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