SpringMVC实现验证码功能

package com.zwk.common;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Component;

import com.zwk.constant.Constants;

@Component
public class RandomValidateCode {

    /**
     * 生成代码
     * 
     * @return
     */
    public static String createValidateCode(int size) {
        String seed = "1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM";
        int len = seed.length();
        char[] p = new char[size];
        for (int i = 0; i ) {
            p[i] = seed.charAt((int) Math.floor(Math.random() * len));
        }
        return new String(p);
    }

    private final Random random = new Random();

    private final String randString = "123456789ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";// 随机产生的字符串
    private final int width = 135;// 图片宽
    private final int height = 40;// 图片高
    private final int lineSize = 50;// 干扰线数量
    private final int stringNum = 4;// 随机产生字符数量

    private final int fontSize = 30;// 随机产生字符数量

    /**
     * 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(this.width, this.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, this.width, this.height);
        g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, this.fontSize));
        g.setColor(this.getRandColor(110, 133));
        // 绘制干扰线
        for (int i = 0; i this.lineSize; i++) {
            this.drawLine(g);
        }
        // 绘制随机字符
        String randomString = "";
        for (int i = 1; i this.stringNum; i++) {
            randomString = this.drawString(g, randomString, i);
        }
　　　　 // 将获取得到的randomString存入定义在Constants类的常量，用于接下来校验时获取
        session.removeAttribute(Constants.RANDOM_CODE_KEY);
        session.setAttribute(Constants.RANDOM_CODE_KEY, randomString);
        // System.out.println(randomString);
        g.dispose();
        try {
            // 禁止图像缓存。
            response.setHeader("Pragma", "no-cache");
            response.setHeader("Cache-Control", "no-cache");
            response.setDateHeader("Expires", 0);
            // 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();
        }
    }

    /**
     * 获取随机的字符
     */
    public String getRandomString(int num) {
        return String.valueOf(this.randString.charAt(num));
    }

    /**
     * 绘制干扰线
     */
    private void drawLine(Graphics g) {
        int x = this.random.nextInt(this.width);
        int y = this.random.nextInt(this.height);
        int xl = this.random.nextInt(13);
        int yl = this.random.nextInt(15);
        g.drawLine(x, y, x + xl, y + yl);
    }

    /**
     * 绘制字符串
     */
    private String drawString(Graphics g, String randomString, int i) {
        g.setFont(this.getFont());
        g.setColor(new Color(this.random.nextInt(155), this.random.nextInt(123), this.random.nextInt(176)));
        String rand = String.valueOf(this.getRandomString(this.random.nextInt(this.randString.length())));
        randomString += rand;
        g.translate(this.random.nextInt(3), this.random.nextInt(3));
        g.drawString(rand, (this.width / this.stringNum - 14) * i, this.height - 7);
        return randomString;
    }

    /**
     * 获得字体
     */
    private Font getFont() {
        return new Font("Times New Roman", Font.CENTER_BASELINE, this.fontSize);
    }

    /**
     * 获得颜色
     */
    private Color getRandColor(int fc, int bc) {
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + this.random.nextInt(bc - fc - 16);
        int g = fc + this.random.nextInt(bc - fc - 14);
        int b = fc + this.random.nextInt(bc - fc - 18);
        return new Color(r, g, b);
    }
}

package com.zwk.constant;

public class Constants {

    public static final String RANDOM_CODE_KEY = "RANDOM_CODE_KEY";
　　

}

package com.zwk.controller;

import javax.annotation.Resource;
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.RequestParam;

import com.zwk.common.RandomValidateCode;
import com.zwk.constant.Constants;

@Controller
public class ToolController {
    @Resource
    RandomValidateCode code;
    @RequestMapping("/vcode")
    public void vcode(HttpServletRequest request,HttpServletResponse response) {
        code.getRandcode(request, response);
        System.out.println("进入获取随机生成的验证码");
    }
    @RequestMapping("doLogin")
    public String doLogin(HttpServletRequest request,HttpServletResponse response,@RequestParam String vcode) {
        //获取session中的code
        String sessionCode=(String)request.getSession().getAttribute(Constants.RANDOM_CODE_KEY);
        System.out.println("随机生成："+sessionCode);
        System.out.println("用户输入："+vcode);
        //将随机生成的验证码和用户输入的验证码统一转化成大写或者小写
        vcode=vcode.toLowerCase();
        sessionCode=sessionCode.toLowerCase();
        if(vcode.equals(sessionCode)) {
            request.setAttribute("error", "验证码输入正确");
            return "i18n"; 
        }else {
            request.setAttribute("error", "验证码输入错误");
            return "login";
        }
    }
}

body>

    script type="text/javascript">
    function changecode(){
        document.getElementById(‘vcode‘).src="vcode.html?c="+Math.random();
    }
    script>

    div style="margin: 0 auto;margin-top: 100px; ">
    
        form action="doLogin.html" method="post">
        用户名：input type="text" name="user">br/>
        验证码：    input type="text" name="vcode">
        img id="vcode" alt="换一张" src="vcode.html" onclick="changecode()"/>
        input type="submit">
        form>
        
        br/>span style="color:red">${error }span>
        
    div>

body>