java实现统计字符串中大写字母，小写字母及数字出现次数的方法示例

public class TestSubstring {
  public static void main(String[] args) {
    getCount("adsJKJ3K21AfaAD134F13241d134134s141faAAFDF");
  }
  //统计字符串中，大写字母，小写字母，数字出现的次数
  public static void getCount(String str) {
    int upper = 0;
    int lower = 0;
    int digi = 0;
    for (int i = 0, len = str.length(); i < len; i++) {
      char c = str.charAt(i);
      if (c >= 'A' && c <= 'Z') {
        upper++;
      } else if (c >= 'a' && c <= 'z') {
        lower++;
      } else if (c >= '0' && c <= '9') {
        digi++;
      }
    }
    System.out.println("大写字母:" + upper); //大写字母:13
    System.out.println("小写字母:" + lower); //小写字母:9
    System.out.println("数字:" + digi);   //数字:20
  }
}