参考原文地址:https://www.cnblogs.com/zwwhnly/p/12449818.html
public static void main(String[] args) { //被统计的字符串 String str = "ABC123ABC"; //查找的字符 String searchChar = "B"; int count = 0; //原来的字符串的长度 int origialLength = str.length(); //将字符串中的指定字符去掉 str = str.replace(searchChar, ""); //去掉指定字符的字符串长度 int newLength = str.length(); //指定字符出现的次数 count = origialLength - newLength; System.out.println("字符" + searchChar + "出现的次数为:" + count); }