[code]package com.heima.maps;
import java.util.Comparator;
import java.util.HashMap;
public class Demo3_TreeMap {
public static void main(String[] args) {
String s = "aaaaaaaaabbbbbbbbbbbbbccccccccccccccccccccccccc"; //定义一个字符串
char [] arr = s.toCharArray(); //将字符串转换为字符数组
HashMap<Character, Integer> hm = new HashMap<>(); //定义hashmap集合
for(char c : arr) { //遍历字符串
if (!hm.containsKey(c)) { //判断出现的次数
hm.put(c, 1);
}else {
hm.put(c, hm.get(c)+1);
}
for (Character key : hm.keySet()) {
System.out.println(key + "=" + hm.get(key));
}
}
}
}
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