Java生成验证码

// 页面

<span style="white-space:pre">	</span><li class="other">

<span style="white-space:pre">		</span><input id="ver_code" name="ver_code" type="text" placeholder="输入验证码" /><div><img src="<%=base%>user/checkCode?r=<%=System.currentTimeMillis() %>" id='verifyCode' /></div><a href="javascript:void(0);" onclick="javaScript:changeV();">换一张</a><script type="text/javascript">function changeV(){document.getElementById("verifyCode").src="<%=base%>user/checkCode?r="+Math.random();}</script></li>

// 后台就Java

<pre name="code" class="java"><span style="white-space:pre">	</span>/*** 检查验证码* @throws IOException*/@RequestMapping("/checkCode")public void checkCode(HttpServletRequest request, HttpServletResponse response) throws IOException{// 设置页面不缓存response.setHeader("Pragma", "No-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);response.setContentType("image/jpeg");response.setCharacterEncoding("UTF-8");// 在内存中创建图象int width = 60, height = 20;BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);// 获取图形上下文Graphics g = image.getGraphics();// 生成随机类Random random = new Random();// 设定背景色g.setColor(getRandColor(200, 250));g.fillRect(0, 0, width, height);// 设定字体g.setFont(new Font("Times New Roman", Font.PLAIN, 18));// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到g.setColor(getRandColor(160, 200));for (int i = 0; i < 155; i++) {int x = random.nextInt(width);int y = random.nextInt(height);int xl = random.nextInt(12);int yl = random.nextInt(12);g.drawLine(x, y, x + xl, y + yl);}// 取随机产生的认证码(4位数字)String sRand = "";for (int i = 0; i < 4; i++) {String rand = String.valueOf(random.nextInt(10));sRand += rand;// 将认证码显示到图象中// 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g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));g.drawString(rand, 13 * i + 6, 16);}// 将认证码存入SESSIONrequest.getSession().setAttribute("verifyCode", sRand);// 图象生效g.dispose();// 输出图象到页面ServletOutputStream responseOutputStream = response.getOutputStream();ImageIO.write(image, "JPEG", responseOutputStream);// 以下关闭输入流！responseOutputStream.flush();responseOutputStream.close();}