Java裏使用patchca生成驗證碼

Patchca是Piotr Piastucki寫的一個java驗證碼開源庫，打包成jar文件發佈，patchca使用簡單但功能強大。

本例實現了自定義背景，因爲生成圖片較小，波動太大時會致使部分文字顯示不全，因此更改了濾鏡屬性。

效果圖：

代碼以下：

[java] view plaincopy

1. package com.ninemax.cul.servlet;  

2.   

3. import java.awt.Color;  

4. import java.awt.Graphics;  

5. import java.awt.image.BufferedImage;  

6. import java.awt.image.BufferedImageOp;  

7. import java.io.IOException;  

8. import java.io.OutputStream;  

9. import java.util.ArrayList;  

10. import java.util.List;  

11. import java.util.Random;  

12.   

13. import javax.imageio.ImageIO;  

14. import javax.servlet.ServletException;  

15. import javax.servlet.http.HttpServlet;  

16. import javax.servlet.http.HttpServletRequest;  

17. import javax.servlet.http.HttpServletResponse;  

18. import javax.servlet.http.HttpSession;  

19.   

20. import org.patchca.background.BackgroundFactory;  

21. import org.patchca.color.ColorFactory;  

22. import org.patchca.color.RandomColorFactory;  

23. import org.patchca.filter.ConfigurableFilterFactory;  

24. import org.patchca.filter.library.AbstractImageOp;  

25. import org.patchca.filter.library.WobbleImageOp;  

26. import org.patchca.font.RandomFontFactory;  

27. import org.patchca.service.Captcha;  

28. import org.patchca.service.ConfigurableCaptchaService;  

29. import org.patchca.text.renderer.BestFitTextRenderer;  

30. import org.patchca.text.renderer.TextRenderer;  

31. import org.patchca.word.RandomWordFactory;  

32.   

33. /**  

34.  * 驗證碼生成類  

35.  *  

36.  * 使用開源驗證碼項目patchca生成  

37.  * 依賴jar包：patchca-0.5.0.jar  

38.  * 項目網址：https://code.google.com/p/patchca/  

39.  *  

40.  * @author zyh 

41.  * @version 1.00  2012-7-12 New  

42.  */  

43. public class ValidationCodeServlet extends HttpServlet {  

44.     private static final long serialVersionUID = 5126616339795936447L;  

45.       

46.     private ConfigurableCaptchaService configurableCaptchaService = null;  

47.     private ColorFactory colorFactory = null;  

48.     private RandomFontFactory fontFactory = null;  

49.     private RandomWordFactory wordFactory = null;  

50.     private TextRenderer textRenderer = null;  

51.       

52.     public ValidationCodeServlet() {  

53.         super();  

54.     }  

55.   

56.     /** 

57.      * Servlet銷燬方法,負責銷燬所使用資源. <br> 

58.      */  

59.     public void destroy() {  

60.         wordFactory = null;  

61.         colorFactory = null;  

62.         fontFactory = null;  

63.         textRenderer = null;  

64.         configurableCaptchaService = null;  

65.         super.destroy(); // Just puts "destroy" string in log  

66.     }  

67.   

68.     public void doGet(HttpServletRequest request, HttpServletResponse response)  

69.             throws ServletException, IOException {  

70.         doPost(request, response);  

71.     }  

72.   

73.     public void doPost(HttpServletRequest request, HttpServletResponse response)  

74.             throws ServletException, IOException {  

75.         response.setContentType("image/png");  

76.         response.setHeader("cache", "no-cache");  

77.           

78.         HttpSession session = request.getSession(true);  

79.         OutputStream outputStream = response.getOutputStream();  

80.           

81.         // 獲得驗證碼對象,有驗證碼圖片和驗證碼字符串  

82.         Captcha captcha = configurableCaptchaService.getCaptcha();  

83.         // 取得驗證碼字符串放入Session  

84.         String validationCode = captcha.getChallenge();  

85.         session.setAttribute("validationCode", validationCode);  

86.         // 取得驗證碼圖片並輸出  

87.         BufferedImage bufferedImage = captcha.getImage();  

88.         ImageIO.write(bufferedImage, "png", outputStream);  

89.           

90.         outputStream.flush();  

91.         outputStream.close();  

92.     }  

93.   

94.     /** 

95.      * Servlet初始化方法 

96.      */  

97.     public void init() throws ServletException {  

98.         configurableCaptchaService = new ConfigurableCaptchaService();  

99.           

100.         // 顏色建立工廠,使用必定範圍內的隨機色  

101.         colorFactory = new RandomColorFactory();  

102.         configurableCaptchaService.setColorFactory(colorFactory);  

103.           

104.         // 隨機字體生成器  

105.         fontFactory = new RandomFontFactory();  

106.         fontFactory.setMaxSize(32);  

107.         fontFactory.setMinSize(28);  

108.         configurableCaptchaService.setFontFactory(fontFactory);  

109.           

110.         // 隨機字符生成器,去除掉容易混淆的字母和數字,如o和0等  

111.         wordFactory = new RandomWordFactory();  

112.         wordFactory.setCharacters("abcdefghkmnpqstwxyz23456789");  

113.         wordFactory.setMaxLength(5);  

114.         wordFactory.setMinLength(4);  

115.         configurableCaptchaService.setWordFactory(wordFactory);  

116.           

117.         // 自定義驗證碼圖片背景  

118.         MyCustomBackgroundFactory backgroundFactory = new MyCustomBackgroundFactory();  

119.         configurableCaptchaService.setBackgroundFactory(backgroundFactory);  

120.           

121.         // 圖片濾鏡設置  

122.         ConfigurableFilterFactory filterFactory = new ConfigurableFilterFactory();  

123.           

124.         List<BufferedImageOp> filters = new ArrayList<BufferedImageOp>();  

125.         WobbleImageOp wobbleImageOp = new WobbleImageOp();  

126.         wobbleImageOp.setEdgeMode(AbstractImageOp.EDGE_MIRROR);  

127.         wobbleImageOp.setxAmplitude(2.0);  

128.         wobbleImageOp.setyAmplitude(1.0);  

129.         filters.add(wobbleImageOp);  

130.         filterFactory.setFilters(filters);  

131.           

132.         configurableCaptchaService.setFilterFactory(filterFactory);  

133.           

134.         // 文字渲染器設置  

135.         textRenderer = new BestFitTextRenderer();  

136.         textRenderer.setBottomMargin(3);  

137.         textRenderer.setTopMargin(3);  

138.         configurableCaptchaService.setTextRenderer(textRenderer);  

139.           

140.         // 驗證碼圖片的大小  

141.         configurableCaptchaService.setWidth(82);  

142.         configurableCaptchaService.setHeight(32);  

143.     }  

144.       

145.     /** 

146.      * 自定義驗證碼圖片背景,主要畫一些噪點和干擾線 

147.      */  

148.     private class MyCustomBackgroundFactory implements BackgroundFactory {  

149.         private Random random = new Random();  

150.   

151.         public void fillBackground(BufferedImage image) {  

152.             Graphics graphics = image.getGraphics();  

153.               

154.             // 驗證碼圖片的寬高  

155.             int imgWidth = image.getWidth();  

156.             int imgHeight = image.getHeight();  

157.               

158.             // 填充爲白色背景  

159.             graphics.setColor(Color.WHITE);  

160.             graphics.fillRect(0, 0, imgWidth, imgHeight);  

161.               

162.             // 畫100個噪點(顏色及位置隨機)  

163.             for(int i = 0; i < 100; i++) {  

164.                 // 隨機顏色  

165.                 int rInt = random.nextInt(255);  

166.                 int gInt = random.nextInt(255);  

167.                 int bInt = random.nextInt(255);  

168.                   

169.                 graphics.setColor(new Color(rInt, gInt, bInt));  

170.                   

171.                 // 隨機位置  

172.                 int xInt = random.nextInt(imgWidth - 3);  

173.                 int yInt = random.nextInt(imgHeight - 2);  

174.                   

175.                 // 隨機旋轉角度  

176.                 int sAngleInt = random.nextInt(360);  

177.                 int eAngleInt = random.nextInt(360);  

178.                   

179.                 // 隨機大小  

180.                 int wInt = random.nextInt(6);  

181.                 int hInt = random.nextInt(6);  

182.                   

183.                 graphics.fillArc(xInt, yInt, wInt, hInt, sAngleInt, eAngleInt);  

184.                   

185.                 // 畫5條幹擾線  

186.                 if (i % 20 == 0) {  

187.                     int xInt2 = random.nextInt(imgWidth);  

188.                     int yInt2 = random.nextInt(imgHeight);  

189.                     graphics.drawLine(xInt, yInt, xInt2, yInt2);  

190.                 }  

191.             }  

192.         }  

193.     }  

194. }  

因爲是個Servlet因此web.xml配置以下：

[html] view plaincopy

1. <servlet>  

2.     <servlet-name>validationCode</servlet-name>  

3.     <servlet-class>com.ninemax.cul.servlet.ValidationCodeServlet</servlet-class>  

4.   </servlet>  

5.   

6.   <servlet-mapping>  

7.     <servlet-name>validationCode</servlet-name>  

8.     <url-pattern>/validationCodeServlet.png</url-pattern>  

9.   </servlet-mapping>  

JSP引用(部分)：

[html] view plaincopy

1. <img id="validationCode" alt="驗證碼圖片" title="驗證碼圖片" src="<%=path %>/validationCodeServlet.png" onclick="refreshCode(this)" />  

2. <a id="aRecode" href="javascript:void(0);" onclick="refreshCode()">換一張</a>  

JS從新載入圖片方法(參考)：

[javascript] view plaincopy

1. /** 

2.  * 刷新驗證碼 

3.  * @param imgObj 驗證碼Img元素 

4.  */  

5. function refreshCode(imgObj) {  

6.     if (!imgObj) {  

7.         imgObj = document.getElementById("validationCode");  

8.     }  

9.     var index = imgObj.src.indexOf("?");  

10.     if(index != -1) {  

11.         var url = imgObj.src.substring(0,index + 1);  

12.         imgObj.src = url + Math.random();  

13.     } else {  

14.         imgObj.src = imgObj.src + "?" + Math.random();  

15.     }  

16. }