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

<div>
    <div class="row cl">
        <label class="form-label col-xs-3"><i class="Hui-iconfont">用户名</i></label>
        <div class="formControls col-xs-8">
            <input id="userName" name="userName" type="text" class="input-text size-L" />
        </div>
    </div>
    <div class="row cl">
        <label class="form-label col-xs-3"><i class="Hui-iconfont">密码</i></label>
        <div class="formControls col-xs-8">
            <input id="password" name="password" type="password" class="input-text size-L" />
        </div>
     </div>
     <div class="row cl">
         <div class="formControls col-xs-8 col-xs-offset-3">
              <input id="checks" class="input-text size-L" type="text" value="验证码:" style="width:150px;" />
              <img id="imgVerify" src="" alt="点击更换验证码" /><a href="" rel="nofollow">看不清，换一张</a>
          </div>
     </div>
     <div class="row cl">
          <div class="formControls col-xs-8 col-xs-offset-3">
              <label><input type="checkbox" name="online" id="online" value="" />使我保持登录状态</label>
           </div>
     </div>
     <div class="row cl">
           <div class="formControls col-xs-8 col-xs-offset-3">
               <input name="" type="submit" class="btn btn-success radius size-L" value=" 登    录 " />
               <input name="" type="reset" class="btn btn-default radius size-L" value=" 取    消 " />
           </div>
      </div>
</div>             
<script type="text/javascript">
$(document.body).ready(function () {
        //首次获取验证码
        $("#imgVerify").attr("src","/user/getVerify?"+Math.random());
    });
    //获取验证码
    function getVerify(){
        var src1=document.getElementById('imgVerify')
        src1.src = "/user/getVerify?"+Math.random();
    }
    //校验验证码
    function checkSum(){
        var html1=document.getElementById('loginingForm');
        var inputStr = $("#checks").val();
        if(inputStr!=null && inputStr!="" && inputStr!="验证码:"){
            inputStr = inputStr.toUpperCase();//将输入的字母全部转换成大写
            html1.action="/user/login?inputStr="+inputStr;//提交表单
        }else{
            alert("验证码不能为空!")
        }
    }
    //登录验证
    function doLogin() {
        var userName=document.getElementById('userName').value;
        var password=document.getElementById('password').value;
        if(null==userName||null==password||""==userName||""==password){
            alert('用户名或密码不能为空!');
        }else {
            //校验验证码
            checkSum();
        }
    }
</script>

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:/";
        }
    }