最後效果圖:
1.首先下載jcaptcha的jar包,網上一搜,進入官網便可下載,這裏不多累贅敘述。
2.把jcaptcha,commons-collections,commons-logging的jar包放入項目中。(此處commons-collections,commons-logging包需要到網上另外下載)
3.建立一個驗證碼引擎或者說驗證碼方案類CaptchaEngine,代碼貼上
package hoking.in.jcaptcha;
import java.awt.Color;
import java.awt.Font;
import com.octo.captcha.component.image.backgroundgenerator.BackgroundGenerator;
import com.octo.captcha.component.image.backgroundgenerator.FunkyBackgroundGenerator;
import com.octo.captcha.component.image.fontgenerator.FontGenerator;
import com.octo.captcha.component.image.fontgenerator.RandomFontGenerator;
import com.octo.captcha.component.image.textpaster.RandomTextPaster;
import com.octo.captcha.component.image.textpaster.TextPaster;
import com.octo.captcha.component.image.wordtoimage.ComposedWordToImage;
import com.octo.captcha.component.image.wordtoimage.WordToImage;
import com.octo.captcha.component.word.wordgenerator.RandomWordGenerator;
import com.octo.captcha.component.word.wordgenerator.WordGenerator;
import com.octo.captcha.engine.image.ListImageCaptchaEngine;
import com.octo.captcha.image.gimpy.GimpyFactory;
/**
* 驗證碼引擎-->彩色驗證碼
*/
public class CaptchaEngine extends ListImageCaptchaEngine {
protected void buildInitialFactories() {
// 隨機生成的字符
WordGenerator wordGenerator = new RandomWordGenerator("0123456789");
// 文字顯示的個數
TextPaster textPaster = new RandomTextPaster(4, 5, Color.WHITE);
// 圖片的大小
BackgroundGenerator backgroundGenerator = new FunkyBackgroundGenerator(
80, 30);
// 字體格式
Font[] fontsList = new Font[] { new Font("Arial", 0, 10),
new Font("Tahoma", 0, 10), new Font("Verdana", 0, 10)};
// 文字的大小
FontGenerator fontGenerator = new RandomFontGenerator(new Integer(16),
new Integer(20), fontsList);
WordToImage wordToImage = new ComposedWordToImage(fontGenerator,
backgroundGenerator, textPaster);
addFactory(new GimpyFactory(wordGenerator, wordToImage));
}
}
4.建立一個驗證碼生成類CaptchaServiceSingleton(採用單例模式)
package hoking.in.jcaptcha;
import com.octo.captcha.service.captchastore.FastHashMapCaptchaStore;
import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;
import com.octo.captcha.service.image.ImageCaptchaService;
/**
* 驗證碼圖片生成類--->單例類
*/
public class CaptchaServiceSingleton {
private static ImageCaptchaService instance =
new DefaultManageableImageCaptchaService(new FastHashMapCaptchaStore(),
new CaptchaEngine(),
180,
100000,
75000);
private CaptchaServiceSingleton(){}
public static ImageCaptchaService getInstance(){
return instance;
}
}
5.創建一個Servlet,用它來向葉面輸出一個圖片驗證碼import java.awt.image.BufferedImage;package hoking.in.jcaptcha;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.octo.captcha.service.CaptchaServiceException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* 產生一個圖片驗證碼到輸出流
*/
public class ImageCaptchaServlet extends HttpServlet {
private static final long serialVersionUID = -3718663907013663827L;
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
byte[] captchaChallengeAsJpeg = null;
//創建一個字節數組輸出流實例
ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
try {
//獲取當前session ID
String captchaId = request.getSession().getId();
//利用驗證碼生成類生成驗證碼的緩存圖片實例
BufferedImage challenge = CaptchaServiceSingleton.getInstance()
.getImageChallengeForID(captchaId, request.getLocale());
//JPEG圖片編碼器
JPEGImageEncoder jpegEncoder = JPEGCodec
.createJPEGEncoder(jpegOutputStream);
jpegEncoder.encode(challenge);
} catch (IllegalArgumentException e) {
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
} catch (CaptchaServiceException e) {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
return;
}
//獲取圖片驗證碼的字節數組
captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
// 添加以下響應頭字段:要求客戶端不緩存響應消息體內容
response.setHeader("Cache-Control", "no-store");
response.setHeader("Pragma", "no-cache");
response.setDateHeader("Expires", 0);
//設置響應內容類型
response.setContentType("image/jpeg");
ServletOutputStream sos = response.getOutputStream();
//把圖片驗證碼的字節數組輸出到輸出流中
sos.write(captchaChallengeAsJpeg);
sos.flush();
sos.close();
}
}
至此,使用到的3個類全部完成
6.把servlet配置到web.xml中
<servlet>
<servlet-name>ImageValidate</servlet-name>
<servlet-class>hoking.in.jcaptcha.ImageCaptchaServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageValidate</servlet-name>
<url-pattern>/jcaptcha</url-pattern>
</servlet-mapping>
7.編寫JSP頁面
<a href="javascript:void(0);" οnclick="document.getElementById('imageValidate').src='${pageContext.request.contextPath }/jcaptcha?' + Math.random();">
<img src="${pageContext.request.contextPath }/jcaptcha" border="0" alt="看不清,請點擊圖片換一張" id="imageValidate"> 看不清,點這換一張 </a>
OK,所有工作完成,部署項目運行之後就能看到效果圖上的效果另外附上後臺驗證代碼
//獲取當前用戶的session ID
String sessionId = requset.getSession().getId();
//獲取用戶提交的驗證碼
String captcha = requset.getParameter("imageValidate");
boolean flag = false;
//進行驗證
flag = CaptchaServiceSingleton.getInstance().validateResponseForID(sessionId, captcha);
到此全部結束
最後來一張項目結構圖
PS(幾處需要注意的地方):
1.編寫JSP頁面時:
${pageContext.request.contextPath }/
不寫也行,此處的斜槓也要一起不寫,但是Math.random();
這個JS函數必須加上,具體原因可以參考我另外一篇博文
驗證碼圖片鏈接後面爲什麼要加一個例如Math.random()的JS隨機數生成函數
2.如果有一些程序方法看不懂大可不必深究,畢竟有前輩幫我們開發好了一個完美的車輪,我們在需要時直接拿來用就可以了(當然,如果有人喜歡深究的話,那也很好)