验证码功能的两种实现方式

绝大部分应用都会有验证码这个功能，这个功能与业务无关，是可复用的。

servlet方式

1. web.xml中加入一个servlet

<!-- spring的servlet --><servlet>        <servlet-name>springServlet</servlet-name>        <servlet-class>org.springframework.web.servlet.DispatcherServlet        </servlet-class>        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>classpath:spring-mvc.xml</param-value>        </init-param>        <load-on-startup>1</load-on-startup>        <multipart-config>            <max-file-size>52428800</max-file-size>            <max-request-size>52428800</max-request-size>            <file-size-threshold>0</file-size-threshold>        </multipart-config>    </servlet>    <servlet-mapping>        <servlet-name>springServlet</servlet-name>        <url-pattern>/</url-pattern>    </servlet-mapping>    <!-- 验证码的servlet -->    <servlet>        <servlet-name>CaptchaServlet</servlet-name>        <servlet-class>com.kylin.drugmng.servlet.CaptchaServlet</servlet-class>    </servlet>    <servlet-mapping>        <servlet-name>CaptchaServlet</servlet-name>        <url-pattern>/CaptchaServlet</url-pattern>    </servlet-mapping>

1. CapchaServlet.java

public class CaptchaServlet extends HttpServlet {    private static final long serialVersionUID = 7301233141618834332L;    public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {          response.setHeader("Pragma", "No-cache");          response.setHeader("Cache-Control", "no-cache");          response.setDateHeader("Expires", 0);          response.setContentType("image/jpeg");          //生成随机字串          String verifyCode = CaptchaUtils.generateVerifyCode(4);          //存入会话session          HttpSession session = request.getSession(true);          session.setAttribute("captchaRand", verifyCode.toLowerCase());          //生成图片          int w = 200, h = 80;          CaptchaUtils.outputImage(w, h, response.getOutputStream(), verifyCode);      }  }

1. login.jsp

<span><img id="captchaImg" style="height: 57px; width: 129px;" src="CaptchaServlet"></span>

controller实现

1. loginController.java

@Controller@RequestMapping("/login/")public class LoginController {    //获取验证码    @RequestMapping("drawcheckcode")    @ResponseBody    public void drawCheckCode(HttpServletResponse resp, HttpSession session) throws IOException {        resp.setContentType("image/jpg");        int width = 70;        int height = 25;        Captcha c = Captcha.getInstance();        c.set(width, height);        String checkcode = c.generateCheckcode();        // 验证码放入session        session.setAttribute("cCode", checkcode);        OutputStream os = resp.getOutputStream();        ImageIO.write(c.generateCheckImg(checkcode), "jpg", os);    }    //验证码验证    @RequestMapping("login")    public ModelAndView login(String account, String password, String checkcode,       HttpSession session) {        // session.setMaxInactiveInterval(20);        ModelAndView mav = null;        PageData pd = new PageData();        // 获取session中的验证码        String cCode = (String) session.getAttribute("cCode");        log.info("用户输入的验证码是：" + checkcode + "，内存中保存的验证码是：" + cCode);        // 验证码为null则跳转登录界面        if (checkcode == null) {            mav = new ModelAndView("login");        }        else if (!checkcode.equalsIgnoreCase(cCode)) {// 比对验证码，忽视大小写。验证码错误则返回登录界面            pd.setSuccess(false);            pd.setMessage("验证码错误");            mav = new ModelAndView("login");            mav.addObject("pd", pd);        }        return mav;        }    }

2.login.htm

<img id="captchaimage" class="sureImage"     src="/user/drawcheckcode.htm" onclick="reCheckcode(this)" />

验证码工具类

CaptchaUtils.java

public class CaptchaUtils {    // 使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符    public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";    private static Random random = new Random();    /**     * 使用系统默认字符源生成验证码     *      * @param verifySize     *            验证码长度     * @return     */    public static String generateVerifyCode(int verifySize) {        return generateVerifyCode(verifySize, VERIFY_CODES);    }    /**     * 使用指定源生成验证码     *      * @param verifySize     *            验证码长度     * @param sources     *            验证码字符源     * @return     */    public static String generateVerifyCode(int verifySize, String sources) {        if (sources == null || sources.length() == 0) {            sources = VERIFY_CODES;        }        int codesLen = sources.length();        Random rand = new Random(System.currentTimeMillis());        StringBuilder verifyCode = new StringBuilder(verifySize);        for (int i = 0; i < verifySize; i++) {            verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));        }        return verifyCode.toString();    }    /**     * 生成随机验证码文件,并返回验证码值     *      * @param w     * @param h     * @param outputFile     * @param verifySize     * @return     * @throws IOException     */    public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException {        String verifyCode = generateVerifyCode(verifySize);        outputImage(w, h, outputFile, verifyCode);        return verifyCode;    }    /**     * 输出随机验证码图片流,并返回验证码值     *      * @param w     * @param h     * @param os     * @param verifySize     * @return     * @throws IOException     */    public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException {        String verifyCode = generateVerifyCode(verifySize);        outputImage(w, h, os, verifyCode);        return verifyCode;    }    /**     * 生成指定验证码图像文件     *      * @param w     * @param h     * @param outputFile     * @param code     * @throws IOException     */    public static void outputImage(int w, int h, File outputFile, String code) throws IOException {        if (outputFile == null) {            return;        }        File dir = outputFile.getParentFile();        if (!dir.exists()) {            dir.mkdirs();        }        try {            outputFile.createNewFile();            FileOutputStream fos = new FileOutputStream(outputFile);            outputImage(w, h, fos, code);            fos.close();        } catch (IOException e) {            throw e;        }    }    /**     * 输出指定验证码图片流     *      * @param w     * @param h     * @param os     * @param code     * @throws IOException     */    public static void outputImage(int w, int h, OutputStream os, String code) throws IOException {        int verifySize = code.length();        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);        Random rand = new Random();        Graphics2D g2 = image.createGraphics();        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);        Color[] colors = new Color[5];        Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN, Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA,                Color.ORANGE, Color.PINK, Color.YELLOW };        float[] fractions = new float[colors.length];        for (int i = 0; i < colors.length; i++) {            colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];            fractions[i] = rand.nextFloat();        }        Arrays.sort(fractions);        g2.setColor(Color.GRAY);// 设置边框色        g2.fillRect(0, 0, w, h);        Color c = getRandColor(200, 250);        g2.setColor(c);// 设置背景色        g2.fillRect(0, 2, w, h - 4);        // 绘制干扰线        Random random = new Random();        g2.setColor(getRandColor(160, 200));// 设置线条的颜色        for (int i = 0; i < 20; i++) {            int x = random.nextInt(w - 1);            int y = random.nextInt(h - 1);            int xl = random.nextInt(6) + 1;            int yl = random.nextInt(12) + 1;            g2.drawLine(x, y, x + xl + 40, y + yl + 20);        }        // 添加噪点        float yawpRate = 0.05f;// 噪声率        int area = (int) (yawpRate * w * h);        for (int i = 0; i < area; i++) {            int x = random.nextInt(w);            int y = random.nextInt(h);            int rgb = getRandomIntColor();            image.setRGB(x, y, rgb);        }        shear(g2, w, h, c);// 使图片扭曲        g2.setColor(getRandColor(100, 160));        int fontSize = h - 4;        Font font = new Font("Algerian", Font.ITALIC, fontSize);        g2.setFont(font);        char[] chars = code.toCharArray();        for (int i = 0; i < verifySize; i++) {            AffineTransform affine = new AffineTransform();            affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1),                    (w / verifySize) * i + fontSize / 2, h / 2);            g2.setTransform(affine);            g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);        }        g2.dispose();        ImageIO.write(image, "jpg", os);    }    private static Color getRandColor(int fc, int bc) {        if (fc > 255)            fc = 255;        if (bc > 255)            bc = 255;        int r = fc + random.nextInt(bc - fc);        int g = fc + random.nextInt(bc - fc);        int b = fc + random.nextInt(bc - fc);        return new Color(r, g, b);    }    private static int getRandomIntColor() {        int[] rgb = getRandomRgb();        int color = 0;        for (int c : rgb) {            color = color << 8;            color = color | c;        }        return color;    }    private static int[] getRandomRgb() {        int[] rgb = new int[3];        for (int i = 0; i < 3; i++) {            rgb[i] = random.nextInt(255);        }        return rgb;    }    private static void shear(Graphics g, int w1, int h1, Color color) {        shearX(g, w1, h1, color);        shearY(g, w1, h1, color);    }    private static void shearX(Graphics g, int w1, int h1, Color color) {        int period = random.nextInt(2);        boolean borderGap = true;        int frames = 1;        int phase = random.nextInt(2);        for (int i = 0; i < h1; i++) {            double d = (double) (period >> 1)                    * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);            g.copyArea(0, i, w1, 1, (int) d, 0);            if (borderGap) {                g.setColor(color);                g.drawLine((int) d, i, 0, i);                g.drawLine((int) d + w1, i, w1, i);            }        }    }    private static void shearY(Graphics g, int w1, int h1, Color color) {        int period = random.nextInt(40) + 10; // 50;        boolean borderGap = true;        int frames = 20;        int phase = 7;        for (int i = 0; i < w1; i++) {            double d = (double) (period >> 1)                    * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);            g.copyArea(i, 0, 1, h1, 0, (int) d);            if (borderGap) {                g.setColor(color);                g.drawLine(i, (int) d, i, 0);                g.drawLine(i, (int) d + h1, i, h1);            }        }    }    public static void main(String[] args) throws IOException {        File dir = new File("F:/verifies");        int w = 200, h = 80;        for (int i = 0; i < 50; i++) {            String verifyCode = generateVerifyCode(4);            File file = new File(dir, verifyCode + ".jpg");            outputImage(w, h, file, verifyCode);        }    }

Captcha.java

public class Captcha {    private int width;    private int height;    private int num;    private String code;    private static final Random ran = new Random();    private static Captcha captcha;    private Captcha(){        //code = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";        code="01abcde23fghi45jkmnpqrstu67vwxyz89";        num = 4;    }    public static Captcha getInstance() {        if(captcha==null) captcha = new Captcha();        return captcha;    }    public void set(int width,int height,int num,String code) {        this.width = width;        this.height = height;        this.setNum(num);        this.setCode(code);    }    public void set(int width,int height) {        this.width = width;        this.height = height;    }    public int getWidth() {        return width;    }    public void setWidth(int width) {        this.width = width;    }    public int getHeight() {        return height;    }    public void setHeight(int height) {        this.height = height;    }    public int getNum() {        return num;    }    public void setNum(int num) {        this.num = num;    }    public String getCode() {        return code;    }    public void setCode(String code) {        this.code = code;    }    public String generateCheckcode() {        StringBuffer cc = new StringBuffer();        for(int i=0;i<num;i++) {            cc.append(code.charAt(ran.nextInt(code.length())));        }        return cc.toString();    }    public BufferedImage generateCheckImg(String checkcode) {        //创建一个图片对象        BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);        //获取图片对象的画笔        Graphics2D graphic = img.createGraphics();        graphic.setColor(Color.WHITE);        graphic.fillRect(0, 0, width, height);        graphic.setColor(Color.BLACK);        graphic.drawRect(0, 0, width-1, height-1);        Font font = new Font("宋体",Font.BOLD+Font.ITALIC,(int)(height*0.8));        graphic.setFont(font);        for(int i=0;i<num;i++) {            graphic.setColor(new Color(ran.nextInt(180),ran.nextInt(180),ran.nextInt(180)));            graphic.drawString(String.valueOf(checkcode.charAt(i)), i*(width/num)+4, (int)(height*0.8));        }        //加一些点        for(int i=0;i<(width+height);i++) {            graphic.setColor(new Color(ran.nextInt(255),ran.nextInt(255),ran.nextInt(255)));            graphic.drawOval(ran.nextInt(width), ran.nextInt(height), 1, 1);        }        //加一些线        //for(int i=0;i<4;i++) {        //  graphic.setColor(new Color(ran.nextInt(255),ran.nextInt(255),ran.nextInt(255)));        //  graphic.drawLine(0, ran.nextInt(height), width, ran.nextInt(height));        //}        return img;    }