/**
 * @Description:生成文件名的工具类包含0-9，a-z和A-Z
 * @author: xiaojie
 * @date: 2021.07.28
 */
public class StringUtils {
        public static String getString(int length) {
            char[] charArray = new char[length];
            for (int i = 0; i < length; i++) {
                Random r = new Random();
                int n = r.nextInt(123);
                while (n < 48 || (n > 57 && n < 65) || (n > 90 && n < 97) || n > 122) {
                    n = r.nextInt(123);
                }
                charArray[i] = (char) n;
            }
            return String.valueOf(charArray);
        }
        public static void main(String[] args) {
            System.out.println(getString(15));
            //dZFdmrv1p85gIfI
        }
}