2fa verification code error

First, the basic process: Produce a Captcha page (very small) → embed in the form → Click to refresh the page → form submit validation. Second, the method: 1, the definition testaction, realizes the drawing method Package com.zhuguang.action; Import Java.awt.Color; Import Java.awt.Font; Import Java.awt.Graphics; Import Java.awt.image.BufferedImage; Import Java.util.Map; Import Javax.servlet.http.HttpServletResponse; Import Org.apache.struts2.interceptor.ServletResponseAware; Impo

{Code...} is this #039; the user name must be 3-5 Characters #039; can it be passed out of functioncheckLength? Array ('user', 'checklength', 'username must be 3-5 bits, 0, 'function', 3, array (3, 5 )), Can the 'user name must be 3-5 bits passed from function checkLength? Reply content: Array ('user', 'checklength', 'username must be 3-5 bits, 0, 'function', 3, array (3, 5 )), Can the 'user name must be 3-5 bits passed from function checkLengt

First of all, a question: in the development of the site, the use of verification code to prevent malicious submission of the form, then how to implement when the verification code error, just refresh the verification

PHP generates an example of a picture verification code to explain, In this paper, we demonstrate 5 kinds of verification codes, and describe the function of generating verification code. PHP generated Verification

is only used to generate a single imageservlet. To implement the replacement function, you can add a suffix, which makes each request URL different (with random number sometimes error, for specific reasons please google).The ②imageservlet class inherits the HttpServlet class, overriding the Doget method. To generate a verification code and render it as a picture

(HttpServletRequest request, httpservletresponse response)throwsioexception{3String piccode = (string) request.getsession (). getattribute ("Piccode");4String Checkcode = Request.getparameter ("Checkcode");5Checkcode =checkcode.touppercase ();6Response.setcontenttype ("TEXT/HTML;CHARSET=GBK");7PrintWriter out =Response.getwriter ();8 if(Checkcode.equals (Piccode)) {9Out.println ("Verify code entered correctly! ");Ten}Else{ OneOut.println ("

The following is the verification code generated. The result is tested on this site by the programmer. No error is reported. If there is something you don't understand, you can reply. The programmer will explain what you don't know. I hope I will get something from you. Session_start (); $ Nums = rand ); $ _ SESSION [nums] = $ nums; $ Imgs = ImageCre

Problem: WebApp Phone Verification Code login often appear captcha error login failed.Analysis Reason: The authentication method of the login is written on the service side through the general processing program, each time through the Ajax access to the general processing program to return the success or failure, finally, the foreground input mobile phone number