java生成验证码

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1. 需要的jar包: patchca.jar: http://code.google.com/p/patchca/

patchca使用LGPL协议: GNU Lesser General Public License

2. 请求验证码的 JSP: validate.jsp

3. 产生验证码的 Servlet: ValidationCode.java

4. 验证验证码的 Servlet: ValidateCode.java

验证过程: validate.jsp请求验证码 -> ValidationCode.java生成验证码图片和相应的字符给validate.jsp -> 用户输入验证码 -> ValidateCode.java验证用户的验证码是否输入正确.

================================== validate.jsp ==================================

<%@pagelanguage="java"contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<!DOCTYPEhtmlPUBLIC"-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<metahttp-equiv="Content-Type"content="text/html; charset=UTF-8">

<title>Insert title here</title>

</head>

<body>

<imgsrc="ValidationCode">

<formaction="ValidateCode"method="post">

<inputtype="text"name="validateCode"/>

<inputtype="submit"value="Submit"/>

</form>

</body>

</html>

================================== ValidateCode.java ==================================

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

/**

* Servlet implementation class Validate

publicclass ValidateCodeextends HttpServlet {

privatestaticfinallong serialVersionUID = 1L;

public ValidateCode() {

super();

}

@Override

protectedvoid doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException,

IOException {

String validateCode = request.getParameter("validateCode");

HttpSession session = request.getSession();

// 从session中取得验证码与用户输入的验证码进行比较

String storedValidateCode = (String) session.getAttribute(session.getId());

response.setHeader("Content-type","text/html; charset=UTF-8");

if (validateCode.equalsIgnoreCase(storedValidateCode)) {

response.getWriter().println("验证码输入正确: " + validateCode);

} else {

response.getWriter().println("验证码输入错误: " + validateCode);

}

@Override

protectedvoid doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException,

IOException {

doGet(request, response);

}

================================== ValidationCode.java ==================================

import java.awt.image.BufferedImage;

import java.io.IOException;

import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.patchca.color.GradientColorFactory;

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.RippleFilterFactory;

import org.patchca.filter.predefined.WobbleRippleFilterFactory;

import org.patchca.service.Captcha;

import org.patchca.service.ConfigurableCaptchaService;

/**

* Servlet implementation class ValidateCode

publicclass ValidationCodeextends HttpServlet {

privatestaticfinallong serialVersionUID = 1L;

public ValidationCode() {

super();

}

// 关键之处，产生图片

@Override

protectedvoid doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException,

IOException {

response.setContentType("image/png");

ValidateEntry ve = new ValidateEntry();

HttpSession session = request.getSession();

session.setAttribute(session.getId(), ve.getCode());// 验证码保存在session中

ServletOutputStream out = response.getOutputStream();

BufferedImage img = ve.getImage();

ImageIO.write(img, "png", out);

out.close();

}

@Override

protectedvoid doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException,

IOException {

doGet(request, response);

}

protectedclass ValidateEntry {

String code;

BufferedImage image;

ValidateEntry() {

createEntry();

}

public String getCode() {

return code;

}

public BufferedImage getImage() {

return image;

}

private void createEntry() {

ConfigurableCaptchaService cs =new ConfigurableCaptchaService();

cs.setColorFactory(new GradientColorFactory());

switch ((int) (System.currentTimeMillis() % 6)) {

case 0:

cs.setFilterFactory(new CurvesRippleFilterFactory(cs.getColorFactory()));

break;

case 1:

cs.setFilterFactory(new MarbleRippleFilterFactory());

break;

case 2:

cs.setFilterFactory(new DoubleRippleFilterFactory());

break;

case 3:

cs.setFilterFactory(new WobbleRippleFilterFactory());

break;

case 4:

cs.setFilterFactory(new DiffuseRippleFilterFactory());

break;

case 5:

cs.setFilterFactory(new RippleFilterFactory());

break;

}

Captcha captcha = cs.getCaptcha();

code = captcha.getChallenge();

image = captcha.getImage();

}

-------------------------------------------------------以上为网上找的资料-------------------------------------------------------

-------------------------------------------------------以下为本人的测试---------------------------------------------------------

public void LoadCodeImg() throws IOException {response.setHeader("Pragma", "No-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);int width = 75, height = 25;BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);Graphics g = image.getGraphics();Random random = new Random();g.setColor(GetCodeImg.getRandColor(200, 250));g.fillRect(0, 0, width, height);g.setFont(new Font("Times New Roman", Font.PLAIN, 24));g.setColor(GetCodeImg.getRandColor(160, 200));for (int i = 0; i < 155; i++) {int x = random.nextInt(width);int y = random.nextInt(height);int xl = random.nextInt(12);int yl = random.nextInt(12);g.drawLine(x, y, x + xl, y + yl);}String sRand = "";for (int i = 0; i < 4; i++) {// String rand = String.valueOf(random.nextInt(10));String rand = randomString(1);sRand += rand;g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));g.drawString(rand, 15 * i + 6, 20);}session.put("numrand", sRand);//这里是将验证码放在session中，做验证的时候从这里取出来跟用户的输入做比较g.dispose();ImageIO.write(image, "JPEG", response.getOutputStream());}

在jsp页面直接调用这个方法就可以生成验证码了<img src="UserAction!LoadCodeImg"/>