java登录验证码实现代码

川长思鸟来 2022-07-16 01:10 239阅读 0赞

VerifyCodeServlet.java类：

复制代码 代码如下:

package com.spring.controller;  
import java.awt.Color;          
import java.awt.Font;          
import java.awt.Graphics2D;          
import java.awt.image.BufferedImage;          
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 org.springframework.stereotype.Controller;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RequestMethod;  
@Controller  
public class VerifyCodeServlet extends HttpServlet \{  
  // 验证码图片的宽度。          
    private int width = 60;          
    // 验证码图片的高度。          
    private int height = 20;          
    // 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' \};          
    /\*\*        
     \* 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 ="80";          
        // 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="xuan/verifyCode",method=RequestMethod.GET)  
    public void service(HttpServletRequest req, HttpServletResponse resp)          
            throws ServletException, java.io.IOException \{  
        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(Color.WHITE);          
        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.PLAIN, 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(12);          
            int yl = random.nextInt(12);          
            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 = 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。          
            g.setColor(new Color(red, green, blue));          
            g.drawString(strRand, (i + 1) \* 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", 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();          
    \}          
\}

ResultServlet.java:

复制代码 代码如下:

package com.spring.controller;  
import java.io.IOException;          
import java.io.PrintWriter;          
import javax.servlet.ServletException;                 
import javax.servlet.http.HttpServletRequest;          
import javax.servlet.http.HttpServletResponse;  
import org.springframework.stereotype.Controller;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RequestMethod;  
@Controller  
public class ResultServlet \{  
     @RequestMapping(value="resultServlet/validateCode",method=RequestMethod.POST)  
     public void doPost(HttpServletRequest request, HttpServletResponse response)          
             throws ServletException, IOException \{          
         response.setContentType("text/html;charset=utf-8");          
         String validateC = (String) request.getSession().getAttribute("validateCode");          
         String veryCode = request.getParameter("c");          
         PrintWriter out = response.getWriter();          
         if(veryCode==null||"".equals(veryCode))\{          
             out.println("验证码为空");          
         \}else\{          
             if(validateC.equals(veryCode))\{          
                 out.println("验证码正确");          
             \}else\{          
                 out.println("验证码错误");          
             \}          
         \}          
         out.flush();          
         out.close();          
     \}          
\}

jsp页面：

复制代码 代码如下:

<%@ page language="java" contentType="text/html; charset=UTF-8"        
    pageEncoding="UTF-8"%>        
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">        
<html>        
    <head>        
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
        <title>test verify code</title>   
    </head>   
    <body>        
        <input id="veryCode" name="veryCode" type="text"/>        
        <img id="imgObj"  alt="" src="xuan/verifyCode"/>        
        <a href="\#" οnclick="changeImg()">换一张</a>        
        <input type="button" value="验证" οnclick="isRightCode()"/>        
        <div id="info"></div>        
    </body>        
</html>  
<script type="text/javascript">  
 function changeImg()\{      
    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();      
    urlurl = url.substring(0,17);      
    if((url.indexOf("&")>=0))\{      
        urlurl = url + "×tamp=" + timestamp;      
    \}else\{      
        urlurl = url + "?timestamp=" + timestamp;      
    \}      
    return url;      
\}      
function isRightCode()\{      
    var code = $("\#veryCode").attr("value");      
    code = "c=" + code;      
    $.ajax(\{      
        type:"POST",      
        url:"resultServlet/validateCode",      
        data:code,      
        success:callback      
    \});      
\}      
function callback(data)\{      
    $("\#info").html(data);      
\}   
</script>