最近在用ssm框架做一个管理系统，做到登录验证时，使用了下面的代码生成图片验证码，最终的效果如下图。

Java类

public class RandomValidateCode { public static final String RANDOMCODEKEY = "randomcode_key";//放到session中的key private Random random = new Random(); private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生的字符串 private int width = 80;//图片宽 private int height = 26;//图片高 private int lineSize = 40;//干扰线数量 private int stringNum = 4;//随机产生字符数量 /** * 生成随机图片 */ public void getRandcode(HttpServletRequest request, HttpServletResponse response) { HttpSession session = request.getSession(); //BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类 BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR); //产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作 Graphics g = image.getGraphics(); g.fillRect(0, 0, width, height); g.setFont(new Font("Times New Roman",Font.ROMAN_BASELINE,18)); g.setColor(getRandColor(160, 200)); //绘制干扰线 for(int i=0;i<=lineSize;i++){ drowLine(g); } //绘制随机字符 String randomString = ""; for(int i=1;i<=stringNum;i++){ randomString=drowString(g,randomString,i); } session.removeAttribute(RANDOMCODEKEY); session.setAttribute(RANDOMCODEKEY, randomString); g.dispose(); try { //将内存中的图片通过流动形式输出到客户端 ImageIO.write(image, "JPEG", response.getOutputStream()); } catch (Exception e) { e.printStackTrace(); } } /* * 获得字体 */ private Font getFont(){ return new Font("Fixedsys",Font.CENTER_BASELINE,18); } /* * 获得颜色 */ private Color getRandColor(int fc,int bc){ if(fc > 255) fc = 255; if(bc > 255) bc = 255; int r = fc + random.nextInt(bc-fc-16); int g = fc + random.nextInt(bc-fc-14); int b = fc + random.nextInt(bc-fc-18); return new Color(r,g,b); } /* * 绘制字符串 */ private String drowString(Graphics g,String randomString,int i){ g.setFont(getFont()); g.setColor(new Color(random.nextInt(101),random.nextInt(111),random.nextInt(121))); String rand = String.valueOf(getRandomString(random.nextInt(randString.length()))); randomString +=rand; g.translate(random.nextInt(3), random.nextInt(3)); g.drawString(rand, 13*i, 16); return randomString; } /* * 绘制干扰线 */ private void drowLine(Graphics g){ int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(13); int yl = random.nextInt(15); g.drawLine(x, y, x+xl, y+yl); } /* * 获取随机的字符 */ public String getRandomString(int num){ return String.valueOf(randString.charAt(num)); }}

Controller

@RequestMapping(value="/checkCode") public void checkCode(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //设置相应类型,告诉浏览器输出的内容为图片 response.setContentType("image/jpeg"); //设置响应头信息，告诉浏览器不要缓存此内容 response.setHeader("pragma", "no-cache"); response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expire", 0); RandomValidateCode randomValidateCode = new RandomValidateCode(); try { randomValidateCode.getRandcode(request, response);//输出图片方法 } catch (Exception e) { e.printStackTrace(); } }

前端jsp页面表单，显示验证码

<div class="layui-form-item"> <div class="layui-row"> <div class="layui-col-xs7"> <label class="layadmin-user-login-icon layui-icon layui-icon-vercode" for="LAY-user-login-vercode"></label> <input type="text" name="code" id="LAY-user-login-vercode" lay-verify="required" placeholder="图形验证码" class="layui-input"> </div> <div class="layui-col-xs5"> <div style="margin-left: 10px;"> <img src="${pageContext.request.contextPath}checkCode" class="layadmin-user-login-codeimg" id="LAY-user-get-vercode" onclick="this.src=this.src+'?'" alt=""> </div> </div> </div> </div>

将上述的代码直接复制到项目就可以直接使用了。

总结

以上所述是小编给大家介绍的java生成图片验证码功能，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！
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