后端验证码工具类

工具类:

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;

/**
 * 验证码工具类
 * 
 * @author hsh
 */
public class CodeUtil {
    // 图片的宽度
    private int width = 160;
    // 图片的高度
    private int height = 28;
    // 验证码字符个数
    private int codeCount = 4;
    // 验证码干扰线数
    private int lineCount = 150;
    // 验证码
    private String code = null;
    // 验证码图片Buffer
    private BufferedImage buffImg = null;

    // 验证码字符集 排除较难分辨的 I 1
    private char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '2', '3', '4', '5', '6', '7', '8', '9' };

    public CodeUtil() {
        this.creatCodeImage();
    }

    /**
     * 
     * @param width
     *            图片宽
     * @param height
     *            图片高
     */
    public CodeUtil(int width, int height) {
        this.width = width;
        this.height = height;
        this.creatCodeImage();
    }

    /**
     * 
     * @param width
     *            图片宽
     * @param height
     *            图片高
     * @param codeCount
     *            字符个数
     * @param lineCount
     *            干扰线条数
     */
    public CodeUtil(int width, int height, int codeCount, int lineCount) {
        this.width = width;
        this.height = height;
        this.codeCount = codeCount;
        this.lineCount = lineCount;
        this.creatCodeImage();
    }

    public void creatCodeImage() {
        int x = 0, fontHeight = 0, codeY = 0;
        int red = 0, green = 0, blue = 0;

        x = width / (codeCount + 2);// 每个字符的宽度
        fontHeight = height - 2;// 字体的高度
        codeY = height - 4;

        // 图像buffer
        /*
         * TYPE_INT_RGB:表示一个图像它具有合成整数像素的8位RGB颜色分量。
         */
        buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = buffImg.createGraphics();
        // 生成随机数
        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
        Font font = new Font("Fixedsys", Font.BOLD, fontHeight);
        g.setFont(font);
        // 干扰线
        for (int i = 0; i < lineCount; i++) {
            int xs = random.nextInt(width);
            int ys = random.nextInt(height);
            int xe = xs + random.nextInt(width / 4);
            int ye = ys + random.nextInt(height / 4);
            red = random.nextInt(255);
            green = random.nextInt(255);
            blue = random.nextInt(255);
            g.setColor(new Color(red, green, blue));
            g.drawLine(xs, ys, xe, ye);
            g.drawOval(xs, ys, xe - xs, (ye - ys) * 2);// 画椭圆
            g.fillOval(xs, ys, xe - xs, (ye - ys) * 2);// 填充
        }

        // randomCode记录随机产生的验证码
        StringBuffer randomCode = new StringBuffer();
        // 随机产生codeCount个字符的验证码。
        for (int i = 0; i < codeCount; i++) {
            String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);
            // 产生随机的颜色值，让输出的每个字符的颜色值都将不同。
            red = random.nextInt(255);
            green = random.nextInt(255);
            blue = random.nextInt(255);
            g.setColor(new Color(red, green, blue));
            g.drawString(strRand, (i + 1) * x, codeY);
            //设置字体旋转
            int zhuan = random.nextInt(20);
            int fzhuan = -random.nextInt(20);
            g.rotate(Math.toRadians(zhuan), 25 * (i - 1), 20); /// 坐标系顺时针转
            g.rotate(Math.toRadians(fzhuan), 25 * (i - 1), 20); /// 坐标系逆时针转
            // 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。
        code = randomCode.toString();

    }

    public void write(String path) throws IOException {
        OutputStream sos = new FileOutputStream(path);
        this.write(sos);
    }

    public void write(OutputStream sos) throws IOException {
        ImageIO.write(buffImg, "png", sos);
        sos.close();
    }

    public BufferedImage getBuffImg() {
        return buffImg;
    }

    public String getCode() {
        return code;
    }

controller类:

@Controller
public class CodeTestController {
    @RequestMapping("/getCode.do")
    public void getCode(HttpServletRequest reqeust, HttpServletResponse response) throws IOException {

        response.setContentType("image/jpeg");
        // 禁止图像缓存。
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        HttpSession session = reqeust.getSession();

        CodeUtil vCode = new CodeUtil(100, 28, 4, 100);
        session.setAttribute("code", vCode.getCode());
        vCode.write(response.getOutputStream());
    }
    
}

html页面:

　　　　　　　　　　　　　　　　 <div>
                                <img src="../getCode.do" id="CreateCheckCode" align="middle" title="点击刷新验证码" onclick="getCode()" style="cursor: pointer;"></img>
                                <input id="inputCode" type="text" value="请输入验证码"/>
                            </div>

 js:

function getCode() {
        $("#CreateCheckCode").attr('src',
                "../getCode.do?nocache=" + new Date().getTime());
    }

 效果: