Java WebServlet生成图片验证码
一，验证码生成属性，方法配置类
//图片类 public class VerifyCode { private int w = 70; private int h = 35; private Random r = new Random(); // {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"} private String[] fontNames = { "宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312" }; // 可选字符 private String codes = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ"; // 背景色 private Color bgColor = new Color(255, 255, 255); // 验证码上的文本 private String text; // 生成随机的颜色 private Color randomColor() { int red = r.nextInt(150); int green = r.nextInt(150); int blue = r.nextInt(150); return new Color(red, green, blue); } // 生成随机的字体 private Font randomFont() { int index = r.nextInt(fontNames.length); String fontName = fontNames[index];// 生成随机的字体名称 int style = r.nextInt(4);// 生成随机的样式, 0(无样式), 1(粗体), 2(斜体), 3(粗体+斜体) int size = r.nextInt(5) + 24; // 生成随机字号, 24 ~ 28 return new Font(fontName, style, size); } // 画干扰线 private void drawLine(BufferedImage image) { int num = 3;// 一共画3条 Graphics2D g2 = (Graphics2D) image.getGraphics(); for (int i = 0; i < num; i++) {// 生成两个点的坐标，即4个值 int x1 = r.nextInt(w); int y1 = r.nextInt(h); int x2 = r.nextInt(w); int y2 = r.nextInt(h); g2.setStroke(new BasicStroke(1.5F)); g2.setColor(Color.BLUE); // 干扰线是蓝色 g2.drawLine(x1, y1, x2, y2);// 画线 } } // 随机生成一个字符 private char randomChar() { int index = r.nextInt(codes.length()); return codes.charAt(index); } // 创建BufferedImage private BufferedImage createImage() { BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = (Graphics2D) image.getGraphics(); g2.setColor(this.bgColor); g2.fillRect(0, 0, w, h); return image; } // ！调用这个方法得到验证码 public BufferedImage getImage() { BufferedImage image = createImage();// 创建图片缓冲区 Graphics2D g2 = (Graphics2D) image.getGraphics();// 得到绘制环境 StringBuilder sb = new StringBuilder();// 用来装载生成的验证码文本 // 向图片中画4个字符 for (int i = 0; i < 4; i++) {// 循环四次，每次生成一个字符 String s = randomChar() + "";// 随机生成一个字母 sb.append(s); // 把字母添加到sb中 float x = i * 1.0F * w / 4; // 设置当前字符的x轴坐标 g2.setFont(randomFont()); // 设置随机字体 g2.setColor(randomColor()); // 设置随机颜色 g2.drawString(s, x, h - 5); // 画图 } this.text = sb.toString(); // 把生成的字符串赋给了this.text drawLine(image); // 添加干扰线 return image; } // 返回验证码图片上的文本 public String getText() { return text; } // 保存图片到指定的输出流 public static void output(BufferedImage image, OutputStream out) throws IOException { ImageIO.write(image, "JPEG", out); } }
二，调用方法生成验证码图片显示
@WebServlet(urlPatterns = "/verifycode") public class VerifyCodeServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { VerifyCode verifyCode = new VerifyCode(); verifyCode.output(verifyCode.getImage(), response.getOutputStream()); String str = verifyCode.getText(); System.out.println(str); } }
界面代码
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>index</title> <script> /* 分析： 点击超链接或者图片，需要换一张 1.给超链接和图片绑定单击事件 2.重新设置图片的src属性值 */ window.onload = function(){ //1.获取图片对象 var img = document.getElementById("Code"); //2.绑定单击事件 var btn = document.getElementById("btnCode"); btn.onclick = function(){ //加时间戳 var date = new Date().getTime(); /*时间永远不重复，则不会访问缓存*/ img.src = "/web01/verifycode?"+date; } } </script> </head> <body> <br/> <img id="Code" src="/web01/verifycode" /> <!--自动生成图片的路径--> <a id="btnCode" href="javascript:void(0)">看不清换一张？</a> </body> </html>
效果
