java统计字符串中出现最多的字符

public class test { public static void main(String[] args) { System.out.println(findMaxValue("abcda")); } public static Character findMaxValue(String str){ if (str == null || str == ""){ return null; } Character maxChar = null; int maxCount = 0; Map<Character,Integer> map = new HashMap<Character, Integer>();//将出现的字母和出现的次数放进一个map中 for(int i=0; i < str.length();i++){ if (map.containsKey(str.charAt(i))) map.put(str.charAt(i),map.get(str.charAt(i))+1);//如果map的key包含该字符，则+1 else map.put(str.charAt(i),1);//如不map的key不包含该字符，则初始化为1 if (maxCount < map.get(str.charAt(i))){ maxCount = map.get(str.charAt(i)); maxChar = str.charAt(i); } } System.out.println("字母"+ maxChar+"出现次数为"+maxCount); return maxChar; } }

运行结果: