频道栏目
首页 > 程序开发 > 综合编程 > 其他综合 > 正文
使用jcaptcha插件生成验证码
2015-07-16 10:22:43         来源:每天的太阳都是新的~汉城  
收藏   我要投稿
1.从官网下载插件,将相应jar包导入到lib目录下 图片
2.创建一个CaptchaServiceSingleton类用来获取jcaptcha自己实现的默认验证码生成器对象DefaultManageableImageCaptchaService(使用单例模式)。
package com.xhc.jcaptcha;

import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;
import com.octo.captcha.service.image.ImageCaptchaService;

public class CaptchaServiceSingleton {
  private static ImageCaptchaService instance = new DefaultManageableImageCaptchaService();
 
     public static ImageCaptchaService getInstance(){
         return instance;
     }
}

3.创建处理验证码生成的servlet
package com.xhc.jcaptcha;

import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.octo.captcha.service.CaptchaServiceException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
public class ImageCaptchaServlet extends HttpServlet {

 public void destroy() {
  super.destroy();
 }
 public void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
   throws ServletException, IOException {
    byte[] captchaChallengeAsJpeg = null;
        // the output stream to render the captcha image as jpeg into
         ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
         try {
         // get the session id that will identify the generated captcha.
         //the same id must be used to validate the response, the session id is a good candidate!
         String captchaId = httpServletRequest.getSession().getId();
         // call the ImageCaptchaService getChallenge method
             BufferedImage challenge = new BufferedImage(68, 22, BufferedImage.TYPE_INT_RGB);
                     challenge=CaptchaServiceSingleton.getInstance().getImageChallengeForID(captchaId,
                             httpServletRequest.getLocale());
             // a jpeg encoder
             JPEGImageEncoder jpegEncoder =
                     JPEGCodec.createJPEGEncoder(jpegOutputStream);
             jpegEncoder.encode(challenge);
         } catch (IllegalArgumentException e) {
             httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
             return;
         } catch (CaptchaServiceException e) {
             httpServletResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
             return;
         }
 
         captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
 
         // flush it in the response
         httpServletResponse.setHeader(Cache-Control, no-store);
         httpServletResponse.setHeader(Pragma, no-cache);
         httpServletResponse.setDateHeader(Expires, 0);
         httpServletResponse.setContentType(image/jpeg);
         ServletOutputStream responseOutputStream =
                 httpServletResponse.getOutputStream();
         responseOutputStream.write(captchaChallengeAsJpeg);
         responseOutputStream.flush();
         responseOutputStream.close();
 }

 public void init(ServletConfig servletConfig) throws ServletException {
  super.init(servletConfig);
 }

}




若导入这两个类时报错 import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; 原因:Eclipse默认把这些受访问限制的API设成了ERROR。只要把Windows-Preferences-Java-Complicer-Errors/Warnings里面的Deprecated and restricted API中的Forbidden references(access rules)选为Warning就可以编译通过。 4.创建用来做验证的servlet
package com.xhc.jcaptcha;

import java.io.IOException;
import java.io.PrintWriter;
import java.net.HttpRetryException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.octo.captcha.service.CaptchaServiceException;

public class ValidationServlet extends HttpServlet {

 public void destroy() {
  super.destroy(); // Just puts destroy string in log
  // Put your code here
 }
 public void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
   throws ServletException, IOException {
  Boolean isResponseCorrect =Boolean.FALSE;
        //remenber that we need an id to validate!
        String captchaId = httpServletRequest.getSession().getId();
        //retrieve the response
        String response = httpServletRequest.getParameter(j_captcha_response);
        // Call the Service method
        httpServletResponse.setContentType(text/html;charset=utf-8);
       PrintWriter wt=httpServletResponse.getWriter();
       
        try {
             isResponseCorrect = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId,
                     response);
             if(isResponseCorrect){
              wt.write(验证码输入成功);
             }else{
              wt.write(验证码输入失败);
             }
         } catch (CaptchaServiceException e) {
              //should not happen, may be thrown if the id is not valid
         }
 }

 
 public void init() throws ServletException {
 }

}



5.配置web.xml

    ImageCaptchaServlet
    com.xhc.jcaptcha.ImageCaptchaServlet
    0
  
  
    ValidationServlet
    com.xhc.jcaptcha.ValidationServlet
  
  
    ImageCaptchaServlet
    /https://blog.csdn.net/sinat_23128227/article/details/servlet/ImageCaptchaServlet
  
  
    ValidationServlet
    /servlet/ValidationServlet
  

 
点击复制链接 与好友分享!回本站首页
相关TAG标签 插件
上一篇:yii2的gradview点击按钮通过get方法传参给数据库
下一篇:二元查找树转换成一个排序的双向链表
相关文章
图文推荐
点击排行

关于我们 | 联系我们 | 广告服务 | 投资合作 | 版权申明 | 在线帮助 | 网站地图 | 作品发布 | Vip技术培训 | 举报中心

版权所有: 红黑联盟--致力于做实用的IT技术学习网站