驗證碼功能的兩種實現方式

絕大部分應用都會有驗證碼這個功能，這個功能與業務無關，是可複用的。

servlet方式

web.xml中加入一個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>

    <!-- 驗證碼的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>

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");  

        //生成隨機字串  
        String verifyCode = CaptchaUtils.generateVerifyCode(4);  
        //存入會話session  
        HttpSession session = request.getSession(true);  
        session.setAttribute("captchaRand", verifyCode.toLowerCase());  
        //生成圖片  
        int w = 200, h = 80;  
        CaptchaUtils.outputImage(w, h, response.getOutputStream(), verifyCode);  
    }  
}

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

controller實現

loginController.java

@Controller
@RequestMapping("/login/")
public class LoginController {
    //獲取驗證碼
    @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();
        // 驗證碼放入session
        session.setAttribute("cCode", checkcode);
        OutputStream os = resp.getOutputStream();
        ImageIO.write(c.generateCheckImg(checkcode), "jpg", os);
    }
    //驗證碼驗證
    @RequestMapping("login")
    public ModelAndView login(String account, String password, String checkcode,       HttpSession session) {
        // session.setMaxInactiveInterval(20);
        ModelAndView mav = null;
        PageData pd = new PageData();
        // 獲取session中的驗證碼
        String cCode = (String) session.getAttribute("cCode");
        log.info("用戶輸入的驗證碼是：" + checkcode + "，內存中保存的驗證碼是：" + cCode);
        // 驗證碼爲null則跳轉登錄界面
        if (checkcode == null) {
            mav = new ModelAndView("login");
        }
        else if (!checkcode.equalsIgnoreCase(cCode)) {// 比對驗證碼，忽視大小寫。驗證碼錯誤則返回登錄界面
            pd.setSuccess(false);
            pd.setMessage("驗證碼錯誤");
            mav = new ModelAndView("login");
            mav.addObject("pd", pd);
        }
        return mav;
        }
    }

2.login.htm

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

驗證碼工具類

CaptchaUtils.java


public class CaptchaUtils {
    // 使用到Algerian字體，系統裏沒有的話需要安裝字體，字體只顯示大寫，去掉了1,0,i,o幾個容易混淆的字符
    public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    private static Random random = new Random();

    /**
     * 使用系統默認字符源生成驗證碼
     * 
     * @param verifySize
     *            驗證碼長度
     * @return
     */
    public static String generateVerifyCode(int verifySize) {
        return generateVerifyCode(verifySize, VERIFY_CODES);
    }

    /**
     * 使用指定源生成驗證碼
     * 
     * @param verifySize
     *            驗證碼長度
     * @param sources
     *            驗證碼字符源
     * @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();
    }

    /**
     * 生成隨機驗證碼文件,並返回驗證碼值
     * 
     * @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;
    }

    /**
     * 輸出隨機驗證碼圖片流,並返回驗證碼值
     * 
     * @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;
    }

    /**
     * 生成指定驗證碼圖像文件
     * 
     * @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;
        }
    }

    /**
     * 輸出指定驗證碼圖片流
     * 
     * @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);// 設置邊框色
        g2.fillRect(0, 0, w, h);

        Color c = getRandColor(200, 250);
        g2.setColor(c);// 設置背景色
        g2.fillRect(0, 2, w, h - 4);

        // 繪製干擾線
        Random random = new Random();
        g2.setColor(getRandColor(160, 200));// 設置線條的顏色
        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);
        }

        // 添加噪點
        float yawpRate = 0.05f;// 噪聲率
        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);// 使圖片扭曲

        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) {
        //創建一個圖片對象
        BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        //獲取圖片對象的畫筆
        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("宋體",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));
        }

        //加一些點
        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);
        }

        //加一些線
        //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;
    }

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驗證碼功能的兩種實現方式

絕大部分應用都會有驗證碼這個功能，這個功能與業務無關，是可複用的。

servlet方式

controller實現

驗證碼工具類

IllegalStateException: Failed to load ApplicationContext

spring data jpa

service層的interface的必要性

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