java实现简单的验证码功能
作者:踢飞足球 时间:2023-08-06 09:21:44
最近要做一个网站,要求实现验证码程序,经过不断调试,终于成功实现功能。
一、验证码生成类
生成验证码的话需要用到java的Graphics类库,画出一个验证码
废话不多说,直接上代码
package verificationCode;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import javax.imageio.ImageIO;
public class generateCode {
private static int width = 150;// 定义图片的width
private static int height = 48;// 定义图片的height
private static int codeCount = 4;// 定义图片上显示验证码的个数
private static int xx = 25;
private static int fontHeight = 42;
private static int codeY = 42;
private static 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' };
/**
* 生成一个map集合
* code为生成的验证码
* codePic为生成的验证码BufferedImage对象
* @return
*/
public static Map<String,Object> generateCodeAndPic() {
// 定义图像buffer
BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// Graphics2D gd = buffImg.createGraphics();
// Graphics2D gd = (Graphics2D) buffImg.getGraphics();
Graphics gd = buffImg.getGraphics();
// 创建一个随机数生成器类
Random random = new Random();
// 将图像填充为白色
gd.setColor(Color.WHITE);
gd.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。
gd.setFont(font);
// 画边框。
gd.setColor(Color.BLACK);
gd.drawRect(0, 0, width - 1, height - 1);
gd.setFont(font);
// 随机产生40条干扰线,使图象中的认证码不易被其它程序探测到。
int red = 0, green = 0, blue = 0;
// 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();
// 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 code = String.valueOf(codeSequence[random.nextInt(36)]);
// 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。
gd.setColor(new Color(red, green, blue));
gd.drawString(code, (i + 1) * xx, codeY);
// 将产生的四个随机数组合在一起。
randomCode.append(code);
}
for (int i = 0; i < 60; i++) {
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。
gd.setColor(new Color(red, green, blue));
int x = random.nextInt(width);
int y = random.nextInt(height);
int xl = random.nextInt(50);
int yl = random.nextInt(50);
gd.drawLine(x, y, x + xl, y + yl);
}
Map<String,Object> map =new HashMap<String,Object>();
//存放验证码
map.put("code", randomCode);
//存放生成的验证码BufferedImage对象
map.put("codePic", buffImg);
return map;
}
public static void main(String[] args) throws Exception {
//创建文件输出流对象
File file = new File("WebRoot/image/"+System.currentTimeMillis()+".jpg");
FileOutputStream out = null;
try {
if (!file.exists()) {
// 先得到文件的上级目录,并创建上级目录,在创建文件
file.getParentFile().mkdir();
file.createNewFile();
}
out = new FileOutputStream(file);
Map<String,Object> map = generateCode.generateCodeAndPic();
ImageIO.write((RenderedImage) map.get("codePic"), "jpeg", out);
System.out.println("验证码的值为:"+map.get("code"));
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
二、验证码验证类
package verificationCode;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@WebServlet("/checkCode")
public class checkCode extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String code = request.getParameter("code");
response.setCharacterEncoding("utf-8");//保证格式正确
response.setContentType("text/html");
// 验证验证码
String sessionCode = request.getSession().getAttribute("code").toString();
if (code != null && !"".equals(code) && sessionCode != null && !"".equals(sessionCode)) {
if (code.equalsIgnoreCase(sessionCode)) {
response.getWriter().println("验证通过!");
} else {
response.getWriter().println("验证失败!");
}
} else {
response.getWriter().println("验证失败!");
}
}
}
三、验证码传输类
用到doget方法
package verificationCode;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import verificationCode.generateCode;
/**
* Servlet implementation class CodeServlet
*/
@WebServlet("/getCode")
public class CodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// 调用工具类生成的验证码和验证码图片
Map<String, Object> codeMap = generateCode.generateCodeAndPic();
// 将四位数字的验证码保存到Session中。
HttpSession session = req.getSession();
session.setAttribute("code", codeMap.get("code").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;
try {
sos = resp.getOutputStream();
ImageIO.write((RenderedImage) codeMap.get("codePic"), "jpeg", sos);
sos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
四、jsp验证demo
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>验证码页面</title>
<script type="text/javascript"
src="${pageContext.request.contextPath}/js/jquery.js"></script>
</head>
<body>
<form action="${pageContext.request.contextPath}/checkCode" method="post">
请输入验证码:<input type="text" name="code" style="width: 80px;" /> <div id=random> <img id="imgObj" alt="验证码"
src="${pageContext.request.contextPath}/getCode"> </div><button id="b01" type="button">改变内容</button><br/> <input
type="submit" value="提交" />
</form>
</body>
<script type="text/javascript">
$(function() {
//response.getWriter().println("验证失败!");
});
$("#b01").click( function changeImg() {
$("#random").html("<img id='imgObj' alt='验证码' src='${pageContext.request.contextPath}/getCode'>")
var imgSrc = $("#imgObj");
var src = imgSrc.attr("src");
imgSrc.attr("src", chgUrl(src));
});
// 时间戳
// 为了使每次生成图片不一致,即不让浏览器读缓存,所以需要加上时间戳
function chgUrl(url) {
var timestamp = (new Date()).valueOf();
url = url.substring(0, 20);
if ((url.indexOf("&") >= 0)) {
url = url + "×tamp=" + timestamp;
} else {
url = url + "?timestamp=" + timestamp;
}
return url;
}
</script>
</html>
总结
虽然只是一个小小的demo,但是实际上用到了许多知识,比如生成验证码的画图,传输验证码doget,验证验证码的dopost和ajax动态更换验证码,麻雀虽小五脏俱全啊。
参考网址: Java实现验证码的产生和验证
来源:https://blog.csdn.net/qq_39263280/article/details/81457299
标签:java,验证码
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