JAVA生成验证码代码

  1  /**
  2      * 生成验证码
  3      * 改造生成验证码的方式，将图片base64形式传到前台，而不是直接传验证码到前台
  4      * @return
  5      * @throws IOException
  6      */
  7     public void imageCode() throws IOException {
  8         HttpServletResponse resp = CommandContext.getResponse();
  9         HttpServletRequest req = CommandContext.getRequest();
 10         String method= req.getMethod();
 11         if("OPTIONS".equals(method)){
 12             return ;
 13         }
 14         Map map=new HashMap();
 15 
 16         // 在内存中创建图象
 17         int width = 65, height = 38;
 18         BufferedImage image = new BufferedImage(width, height,
 19                 BufferedImage.TYPE_INT_RGB);
 20         // 获取图形上下文
 21         Graphics g = image.getGraphics();
 22         // 生成随机类
 23         Random random = new Random();
 24         // 设定背景色
 25         g.setColor(getRandColor(230, 255));
 26         g.fillRect(0, 0, 100, 40);
 27         // 设定字体
 28         g.setFont(new Font("Arial", Font.CENTER_BASELINE | Font.ITALIC, 20));
 29         // 产生0条干扰线，
 30         g.drawLine(0, 0, 0, 0);
 31 
 32         //存放验证码
 33         StringBuffer sRand = new StringBuffer();
 34         for (int i = 0; i < charCount; i++) {
 35             String singleCode = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
 36             sRand.append(singleCode);
 37             // 将认证码显示到图象中
 38             g.setColor(getRandColor(100, 150));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
 39             g.drawString(singleCode, 14 * i + 5, 25);
 40         }
 41         for(int i=0;i<(random.nextInt(5)+5);i++){
 42             g.setColor(new Color(random.nextInt(255)+1,random.nextInt(255)+1,random.nextInt(255)+1));
 43             g.drawLine(random.nextInt(70),random.nextInt(40),random.nextInt(70),random.nextInt(40));
 44             g.drawLine(random.nextInt(70),random.nextInt(40),random.nextInt(70),random.nextInt(40));
 45         }
 46 
 47         HttpSession session = req.getSession();
 48         //获取clientid
 49         String clientId= SystemUtil.getClientId(req);
 50         if(StringUtils.isEmpty(clientId)){
 51             //生成clientid
 52             String userAgent=req.getHeader("User-Agent");
 53             String sessionId=session.getId();
 54             String cip= IpPolicy.getClientIP(req);
 55             clientId=CodeUtil.genClientId(sessionId,cip,userAgent);
 56         }
 57         map.put("clientId", clientId);
 58         if (isValidateCodeCaseSensitive) {
 59             session.setAttribute("randomCode", sRand.toString());
 60             SystemUtil.push2Cache(clientId, sRand.toString());
 61         } else {
 62             session.setAttribute("randomCode", sRand.toString().toLowerCase());
 63             SystemUtil.push2Cache(clientId, sRand.toString().toLowerCase());
 64         }
 65         // 图象生效
 66         g.dispose();
 67         try{
 68 
 69             ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
 70             ImageIO.write(image, "jpg", outputStream);
 71             BASE64Encoder encoder = new BASE64Encoder();
 72             String base64Img = encoder.encode(outputStream.toByteArray());
 73             base64Img="data:image/jpg;base64, "+base64Img.replaceAll("\n", "").replaceAll("\r", "");//删除 \r\n;
 74             map.put("verCode", base64Img);
 75             Object jsonObj = JSONSerializer.toJSON(map);
 76             byte[] json = jsonObj.toString().getBytes("UTF-8");
 77             resp.setContentType("text/plain;chartset=utf-8");
 78             resp.setHeader("Cache-Control", "no-cache");
 79             resp.setHeader("Expires", "0");
 80             resp.setIntHeader("Content-Length", json.length);
 81             ServletOutputStream responseOutputStream = resp.getOutputStream();
 82             responseOutputStream.write(json);
 83             // 以下关闭输入流！
 84             responseOutputStream.flush();
 85             responseOutputStream.close();
 86             // 获得页面key值
 87             return ;
 88         } catch (IOException e) {
 89             logger.error("生产验证码出错",e);
 90             throw new SystemException("生产验证码出错",e);
 91         }
 92     }
 93 
 94 
 95     /**
 96      * 给定范围获得随机颜色
 97      *
 98      * @param fc
 99      * @param bc
100      * @return
101      */
102     Color getRandColor(int fc, int bc) {
103         Random random = new Random();
104         if (fc > 255)
105             fc = 255;
106         if (bc > 255)
107             bc = 255;
108         int r = fc + random.nextInt(bc - fc);
109         int g = fc + random.nextInt(bc - fc);
110         int b = fc + random.nextInt(bc - fc);
111         return new Color(r, g, b);
112     }