封装验证码简单示例

public class AuthCode {
    /**
     * 封装验证码
     */
    public static String createCode(int n){
        String chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        String code = "";
        Random r = new Random();
        for (int i = 0; i < n; i++) {
            int index = r.nextInt(chars.length());
            code += chars.charAt(index);
        }
        return code;
    }
}

public class StaticAuthCode {
    public static void main(String[] args) {
        String code = AuthCode.createCode(6);
        System.out.println("验证码是：" + code);
    }
}