JAVA Map集合

 

import java.util.HashMap;
import java.util.Scanner;

public class Demo01Map {
    public static void main(String[] args) {
        //1,使用Scanner获得用户输入的字符串
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入一个字符串");
        String str = scanner.next();
        //2,创建Map集合，kep是字符串的字符，value是字符的个数
        HashMap<Character,Integer> map =new HashMap<>();
        //3,4
        for(char c :str.toCharArray()){
            if(map.containsKey(c)){
                Integer value =map.get(c);
                value++;
                map.put(c,value);
            }else{
                map.put(c,1);
            }
        }
        for(Character key :map.keySet()){
            Integer value = map.get(key);
            System.out.println(key+"="+value);
        }
    }
}