Comment faire pour insérer un captcha dans une jsp en forme?

Votre code captcha fonctionne sans aucun changement à l'intérieur d'une servlet doGet(...) de la méthode.

package test.captcha;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class CaptchaServlet extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpg");
/*
* Define number characters contains the captcha image, declare global
*/
int iTotalChars = 6;
/*
* Size image iHeight and iWidth, declare globl
*/
int iHeight = 40;
int iWidth = 150;
/*
* font style
*/
Font fntStyle1 = new Font("Arial", Font.BOLD, 30);
Font fntStyle2 = new Font("Verdana", Font.BOLD, 20);
/*
* Possible random characters in the image
*/
Random randChars = new Random();
String sImageCode = (Long.toString(Math.abs(randChars.nextLong()), 36)).substring(0, iTotalChars);
/*
* BufferedImage is used to create a create new image
*/
/*
* TYPE_INT_RGB - does not support transpatency, TYPE_INT_ARGB - support transpatency
*/
BufferedImage biImage = new BufferedImage(iWidth, iHeight, BufferedImage.TYPE_INT_RGB);
Graphics2D g2dImage = (Graphics2D) biImage.getGraphics();
//Draw background rectangle and noisey filled round rectangles
int iCircle = 15;
//g2dImage.fillRect(0, 0, iWidth, iHeight);
for (int i = 0; i < iCircle; i++) {
g2dImage.setColor(new Color(randChars.nextInt(255), randChars.nextInt(255), randChars.nextInt(255)));
int iRadius = (int) (Math.random() * iHeight / 2.0);
int iX = (int) (Math.random() * iWidth - iRadius);
int iY = (int) (Math.random() * iHeight - iRadius);
//g2dImage.fillRoundRect(iX, iY, iRadius * 2, iRadius * 2,100,100);
}
g2dImage.setFont(fntStyle1);
for (int i = 0; i < iTotalChars; i++) {
g2dImage.setColor(new Color(randChars.nextInt(255), randChars.nextInt(255), randChars.nextInt(255)));
if (i % 2 == 0) {
g2dImage.drawString(sImageCode.substring(i, i + 1), 25 * i, 24);
} else {
g2dImage.drawString(sImageCode.substring(i, i + 1), 25 * i, 35);
}
}
/*
* create jpeg image and display on the screen
*/
OutputStream osImage = response.getOutputStream();
ImageIO.write(biImage, "jpeg", osImage);
//osImage.close();
/*
* Dispose function is used destory an image object
*/
g2dImage.dispose();
HttpSession session = request.getSession();
session.setAttribute("dns_security_code", sImageCode);
//System.out.println("Captcha Page :"+session.getAttribute("dns_security_code"));
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
}

créer s'il n'existe pas une application web descripteur: /WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
<servlet>
<servlet-name>CaptchaServlet</servlet-name>
<servlet-class>test.captcha.CaptchaServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CaptchaServlet</servlet-name>
<url-pattern>/captcha-image.jpg</url-pattern>
</servlet-mapping>
</web-app>

OriginalL'auteur Amol

Ici vous allez avec des exemples de code. Espérons que cela aide.

http://captchas.net/sample/jsp/

OriginalL'auteur melbourne-geek

Ce code fonctionne:

//mettre dans votre page jsp

<div class="form-cont">
<img src="CaptchaImg.jpg" alt="image">
</div>
<div class="form-cont">
<input autocomplete="off"  type="text" class="captcha input-elm" tabindex="3"  
placeholder="Captcha Code" name="j_captcha_response" id="j_captcha_response" 
maxlength="4">
</div>
//PUT in YOUR class
String parm = httpServletRequest.getParameter("j_captcha_response");
String captchaKey = (String)session.getAttribute(CaptchaServlet.CAPTCHA_KEY) ;
if(parm.equalsIgnoreCase(captchaKey)){
true
//CODE HERE
}
else{
faLSE
ERROR HERE 
}

OriginalL'auteur Mr. GK