配置web.xml
<servlet><description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>VerifyCodeServlet</servlet-name>
<servlet-class>servlet.VerifyCodeServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>VerifyCodeServlet</servlet-name>
<url-pattern>/patchca.png</url-pattern>
</servlet-mapping>
创建servlet
/*** Copyright(C) 2012, 河北工业职业技术学院.
*
* 模块名称： 登录模块
* 子模块名称： 验证码模块
*
* 备注：
*
* 修改历史：
* 时间 版本号 姓名 修改内容
* 2012-6-7 V1.0 李玮 新建
*/
package servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.awt.Color;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.patchca.color.ColorFactory;
import org.patchca.color.SingleColorFactory;
import org.patchca.filter.predefined.CurvesRippleFilterFactory;
import org.patchca.filter.predefined.DiffuseRippleFilterFactory;
import org.patchca.filter.predefined.DoubleRippleFilterFactory;
import org.patchca.filter.predefined.MarbleRippleFilterFactory;
import org.patchca.filter.predefined.WobbleRippleFilterFactory;
import org.patchca.font.FontFactory;
import org.patchca.font.RandomFontFactory;
import org.patchca.service.ConfigurableCaptchaService;
import org.patchca.text.renderer.BestFitTextRenderer;
import org.patchca.text.renderer.RandomYBestFitTextRenderer;
import org.patchca.text.renderer.SimpleTextRenderer;
import org.patchca.text.renderer.TextRenderer;
import org.patchca.utils.encoder.EncoderHelper;
import org.patchca.word.RandomWordFactory;
/**
* 验证码生成类
*
* 本类的简要描述：
* 使用开源验证码项目patchca生成
* jar包：patchca-0.5.0.jar
* 项目网址：https://code.google.com/p/patchca/
* 项目中文介绍：http://baike.baidu.com/view/6925997.htm?fromTaglist
*
* @author
* @version 1.00 2012-6-7 新建类
*/
public class VerifyCodeServlet extends HttpServlet {
private static final long serialVersionUID = 3796351198097771007L;
private static ConfigurableCaptchaService ccs = null;
private static ColorFactory cf = null;
private static TextRenderer tr = null;
private static RandomFontFactory ff = null;
private static RandomWordFactory rwf = null;
private static Random r = new Random();
//private static CurvesRippleFilterFactory crff = null; //干扰线波纹
//private static MarbleRippleFilterFactory mrff = null; //大理石波纹
//private static DoubleRippleFilterFactory drff = null; //双波纹
private static WobbleRippleFilterFactory wrff = null; //摆波纹
//private static DiffuseRippleFilterFactory dirff = null; //漫波纹
/**
* Constructor of the object.
*/
public VerifyCodeServlet() {
super();
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
super.init();
ccs = new ConfigurableCaptchaService();
cf = new SingleColorFactory(new Color(25, 60, 170));
ff = new RandomFontFactory();
rwf = new RandomWordFactory();
tr = new BestFitTextRenderer();
//crff = new CurvesRippleFilterFactory(ccs.getColorFactory());
//drff = new DoubleRippleFilterFactory();
wrff = new WobbleRippleFilterFactory();
//dirff = new DiffuseRippleFilterFactory();
//mrff = new MarbleRippleFilterFactory();
rwf.setCharacters("123456789");
ff.setRandomStyle(false);
ff.setMaxSize(16);
ff.setMinSize(12);
ccs.setTextRenderer(tr);
ccs.setFontFactory(ff);
ccs.setWordFactory(rwf);
ccs.setColorFactory(cf);
ccs.setWidth(50);
ccs.setHeight(20);
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/png");
response.setHeader("cache", "no-cache");
rwf.setMaxLength(4);
rwf.setMinLength(4);
HttpSession session = request.getSession(true);
OutputStream os = response.getOutputStream();
ccs.setFilterFactory(wrff);
/*switch (r.nextInt(5)) {
case 0:
ccs.setFilterFactory(drff);
break;
case 1:
ccs.setFilterFactory(mrff);
break;
case 2:
ccs.setFilterFactory(drff);
break;
case 3:
ccs.setFilterFactory(wrff);
break;
case 4:
ccs.setFilterFactory(dirff);
break;
}*/
String captcha = EncoderHelper.getChallangeAndWriteImage(ccs, "png", os);
session.setAttribute("captcha", captcha);
os.flush();
os.close();
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
rwf = null;
cf = null;
ccs = null;
ff = null;
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
}