ssm框架登录界面验证码功能

1、先创建一个工具类（用于验证码格式生成）

package com.jixi.utils;import javax.imageio.ImageIO;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.awt.*;import java.awt.image.BufferedImage;import java.util.Random;/** * 验证码生成类 * Created by zhm on 2017/9/30. */public class RandomValidateCode {    public static final String RANDOMCODEKEY= "RANDOMVALIDATECODEKEY";//放到session中的key    //private String randString = "0123456789";//随机产生只有数字的字符串 private String    private String randString = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生只有字母的字符串    //private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";//随机产生数字与字母组合的字符串    private int width = 95;// 图片宽    private int height = 25;// 图片高    private int lineSize = 40;// 干扰线数量    private int stringNum = 4;// 随机产生字符数量    private Random random = new Random();    /*     * 获得字体     */    private Font getFont() {        return new Font("Fixedsys", Font.CENTER_BASELINE, 18);    }    /*     * 获得颜色     */    private Color getRandColor(int fc, int bc) {        if (fc > 255)            fc = 255;        if (bc > 255)            bc = 255;        int r = fc + random.nextInt(bc - fc - 16);        int g = fc + random.nextInt(bc - fc - 14);        int b = fc + random.nextInt(bc - fc - 18);        return new Color(r, g, b);    }    /**     * 生成随机图片     */    public void getRandcode(HttpServletRequest request, HttpServletResponse response) {        HttpSession session = request.getSession();        // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);        Graphics g = image.getGraphics();// 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作        g.fillRect(0, 0, width, height);        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));        g.setColor(getRandColor(110, 133));        // 绘制干扰线        for (int i = 0; i <= lineSize; i++) {            drowLine(g);        }        // 绘制随机字符        String randomString = "";        for (int i = 1; i <= stringNum; i++) {            randomString = drowString(g, randomString, i);        }        //将生成的随机字符串保存到session中，而jsp界面通过session.getAttribute("RANDOMCODEKEY")，        //获得生成的验证码，然后跟用户输入的进行比较        session.removeAttribute(RANDOMCODEKEY);        session.setAttribute(RANDOMCODEKEY, randomString);        g.dispose();        try {            // 将内存中的图片通过流动形式输出到客户端            ImageIO.write(image, "JPEG", response.getOutputStream());        } catch (Exception e) {            e.printStackTrace();        }    }    /*     * 绘制字符串     */    private String drowString(Graphics g, String randomString, int i) {        g.setFont(getFont());        g.setColor(new Color(random.nextInt(101), random.nextInt(111), random                .nextInt(121)));        String rand = String.valueOf(getRandomString(random.nextInt(randString                .length())));        randomString += rand;        g.translate(random.nextInt(3), random.nextInt(3));        g.drawString(rand, 13 * i, 16);        return randomString;    }    /*     * 绘制干扰线     */    private void drowLine(Graphics g) {        int x = random.nextInt(width);        int y = random.nextInt(height);        int xl = random.nextInt(13);        int yl = random.nextInt(15);        g.drawLine(x, y, x + xl, y + yl);    }    /*     * 获取随机的字符     */    public String getRandomString(int num) {        return String.valueOf(randString.charAt(num));    }}

2、设计好jsp登陆界面

 
                
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                                        
                                            
                
                
                    
                                                 看不清，换一张                    
                
                
                    
                                                                                使我保持登录状态                    
                
                
                    
                                                                    
                
            
  

3、通过控制层与页面交互

 /**     * 登录页面生成验证码     */    @RequestMapping(value = "/getVerify")    public void getVerify(HttpServletRequest request, HttpServletResponse response){        response.setContentType("image/jpeg");//设置相应类型,告诉浏览器输出的内容为图片        response.setHeader("Pragma", "No-cache");//设置响应头信息，告诉浏览器不要缓存此内容        response.setHeader("Cache-Control", "no-cache");        response.setDateHeader("Expire", 0);        RandomValidateCode randomValidateCode = new RandomValidateCode();        try {            randomValidateCode.getRandcode(request, response);//输出验证码图片方法        } catch (Exception e) {            e.printStackTrace();        }    }    /**     * 验证登录     * @param model     * @param userName     * @param password     * @param inputStr     * @param session     * @return     */    @RequestMapping(value = "/login", method = RequestMethod.POST)    public String login(Model model, String userName, String password,String inputStr, HttpSession session) {        //从session中获取随机数        String random = (String) session.getAttribute("RANDOMVALIDATECODEKEY");        User user=userService.selectByUserName(userName);        Subject subject = SecurityUtils.getSubject() ;        UsernamePasswordToken token = new UsernamePasswordToken(userName,password);        try {            if(random.equals(inputStr)){                subject.login(token);                model.addAttribute("user", user);                return  "user/login" ;            }else {                model.addAttribute("error","验证码错误");                return "redirect:/";            }        } catch (AuthenticationException e) {            e.printStackTrace();            model.addAttribute("error","用户名或密码错误");            return "redirect:/";        }    }