java验证码功能

后台java代码：

package net.cloudsun.base.controller;

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Random;

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 net.cloudsun.base.service.CheckCodeService;

import net.cloudsun.base.service.UserService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.ResponseBody;

/**

* @author 熊浪

*

*/

@Controller

@RequestMapping(value = "/xuan")

public class VerifyCodeServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

@Autowired

private CheckCodeService checkCodeService;

@Autowired

private UserService userService;

// 验证码图片的宽度。

private int width = 55;

// 验证码图片的高度。

private int height = 30;

// 验证码字符个数

private int codeCount = 4;

private int x = 0;

// 字体高度

private int fontHeight;

private int codeY;

char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',

'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',

'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };

char[] codeSequence_tele = { '0', '1', '2', '3', '4', '5', '6', '7', '8',

'9' };

/**

* 初始化验证图片属性

*/

public void initxuan() throws ServletException {

// 从web.xml中获取初始信息

// 宽度

String strWidth = "70";

// 高度

String strHeight = "30";

// 字符个数

String strCodeCount = "4";

// 将配置的信息转换成数值

try {

if (strWidth != null && strWidth.length() != 0) {

width = Integer.parseInt(strWidth);

}

if (strHeight != null && strHeight.length() != 0) {

height = Integer.parseInt(strHeight);

}

if (strCodeCount != null && strCodeCount.length() != 0) {

codeCount = Integer.parseInt(strCodeCount);

}

} catch (NumberFormatException e) {

}

x = width / (codeCount + 1);

fontHeight = height - 2;

codeY = height - 4;

}

@RequestMapping(value = "/verifyCode/{id}", method = RequestMethod.GET)

public @ResponseBody void service(@PathVariable("id") int id,

HttpServletRequest req, HttpServletResponse resp)

throws ServletException, java.io.IOException {

String type_tele = req.getParameter("type_tele");

initxuan();

// 定义图像buffer

BufferedImage buffImg = new BufferedImage(width, height,

BufferedImage.TYPE_INT_RGB);

Graphics2D g = buffImg.createGraphics();

// 创建一个随机数生成器类

Random random = new Random();

// 将图像填充为白色

g.setColor(new Color(255, 193, 37));

g.fillRect(0, 0, width, height);

// 创建字体，字体的大小应该根据图片的高度来定。

Font font = new Font("Fixedsys", Font.BOLD, fontHeight);

// 设置字体。

g.setFont(font);

// 画边框。

g.setColor(Color.BLACK);

g.drawRect(0, 0, width - 1, height - 1);

// 随机产生160条干扰线，使图象中的认证码不易被其它程序探测到。

// g.setColor(Color.BLACK);

for (int i = 0; i < 10; i++) {

int x = random.nextInt(width);

int y = random.nextInt(height);

int xl = random.nextInt(5);

int yl = random.nextInt(5);

g.drawLine(x, y, x + xl, y + yl);

}

// randomCode用于保存随机产生的验证码，以便用户登录后进行验证。

StringBuffer randomCode = new StringBuffer();

int red = 0, green = 0, blue = 0;

// 随机产生codeCount数字的验证码。

for (int i = 0; i < codeCount; i++) {

// 得到随机产生的验证码数字。

String strRand = " ";

if ('1' == type_tele.charAt(0)) {

strRand = String.valueOf(codeSequence[random.nextInt(30)]);

}

if ('2' == type_tele.charAt(0)) {

strRand = String.valueOf(codeSequence[random.nextInt(30)]);

}

// 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。

red = random.nextInt(255);

green = random.nextInt(255);

blue = random.nextInt(255);

// 用随机产生的颜色将验证码绘制到图像中。

g.setColor(new Color(red, green, blue));

g.drawString(strRand, i * x, codeY);

// 将产生的四个随机数组合在一起。

randomCode.append(strRand);

}

// 将四位数字的验证码保存到Session中。

HttpSession session = req.getSession();

session.setAttribute("validateCode" + id, randomCode.toString());

// 禁止图像缓存。

resp.setHeader("Pragma", "no-cache");

resp.setHeader("Cache-Control", "no-cache");

resp.setDateHeader("Expires", 0);

resp.setContentType("image/jpeg");

// 将图像输出到Servlet输出流中。

ServletOutputStream sos = resp.getOutputStream();

ImageIO.write(buffImg, "jpeg", sos);

sos.close();

}

@RequestMapping(value = "/valiCode", method = RequestMethod.POST)

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=utf-8");

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

String validateC = (String) request.getSession().getAttribute(

"validateCode" + id);//获得存储在session中的验证码

String veryCode = request.getParameter("c").toLowerCase();//获得前台输入的验证码

PrintWriter out = response.getWriter();

if (veryCode == null || "".equals(veryCode)) {

out.println("1");

} else {

if (validateC == null) {

out.println("3");

} else {

if (validateC.toLowerCase().equals(veryCode)) {

out.println("0");

} else {

out.println("2");

}

}

}

out.flush();

out.close();

}

}

前台jsp代码：

<img src="/xuan/verifyCode/1?type_tele=1" width="51px;" id="imgObj" />js校验就不说了。

效果图：