登录验证码插件

Cpacha.java:

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.util.Random;

public class CpachaUtil {
    /**
     * 验证码来源
     */
    final private char[] code = { '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i',
            'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F',
            'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
    /**
     * 字体
     */
    final private String[] fontNames = new String[] { "黑体", "宋体", "Courier", "Arial", "Verdana", "Times", "Tahoma",
            "Georgia" };
    /**
     * 字体样式
     */
    final private int[] fontStyles = new int[] { Font.BOLD, Font.ITALIC | Font.BOLD };

    /**
     * 验证码长度 默认4个字符
     */
    private int vcodeLen = 4;
    /**
     * 验证码图片字体大小 默认17
     */
    private int fontsize = 21;
    /**
     * 验证码图片宽度
     */
    private int width = (fontsize + 1) * vcodeLen + 10;
    /**
     * 验证码图片高度
     */
    private int height = fontsize + 12;
    /**
     * 干扰线条数 默认3条
     */
    private int disturbline = 3;

    public CpachaUtil() {
    }

    /**
     * 指定验证码长度
     * 
     * @param vcodeLen 验证码长度
     */
    public CpachaUtil(int vcodeLen) {
        this.vcodeLen = vcodeLen;
        this.width = (fontsize + 1) * vcodeLen + 10;
    }

    /**
     * 指定验证码长度、图片宽度、高度
     * 
     * @param vcodeLen
     * @param width
     * @param height
     */
    public CpachaUtil(int vcodeLen, int width, int height) {
        this.vcodeLen = vcodeLen;
        this.width = width;
        this.height = height;
    }

    /**
     * 生成验证码图片
     * 
     * @param vcode    要画的验证码
     * @param drawline 是否画干扰线
     * @return
     */
    public BufferedImage generatorVCodeImage(String vcode, boolean drawline) {
        // 创建验证码图片
        BufferedImage vcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics g = vcodeImage.getGraphics();
        // 填充背景色
        g.setColor(new Color(246, 240, 250));
        g.fillRect(0, 0, width, height);
        if (drawline) {
            drawDisturbLine(g);
        }
        // 用于生成伪随机数
        Random ran = new Random();
        // 在图片上画验证码
        for (int i = 0; i < vcode.length(); i++) {
            // 设置字体
            g.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)],
                    fontsize));
            // 随机生成颜色
            g.setColor(getRandomColor());
            // 画验证码
            g.drawString(vcode.charAt(i) + "", i * fontsize + 10, fontsize + 5);
        }
        // 释放此图形的上下文以及它使用的所有系统资源
        g.dispose();

        return vcodeImage;
    }

    /**
     * 获得旋转字体的验证码图片
     * 
     * @param vcode
     * @param drawline 是否画干扰线
     * @return
     */
    public BufferedImage generatorRotateVCodeImage(String vcode, boolean drawline) {
        // 创建验证码图片
        BufferedImage rotateVcodeImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2d = rotateVcodeImage.createGraphics();
        // 填充背景色
        g2d.setColor(new Color(246, 240, 250));
        g2d.fillRect(0, 0, width, height);
        if (drawline) {
            drawDisturbLine(g2d);
        }
        // 在图片上画验证码
        for (int i = 0; i < vcode.length(); i++) {
            BufferedImage rotateImage = getRotateImage(vcode.charAt(i));
            g2d.drawImage(rotateImage, null, (int) (this.height * 0.7) * i, 0);
        }
        g2d.dispose();
        return rotateVcodeImage;
    }

    /**
     * 生成验证码
     * 
     * @return 验证码
     */
    public String generatorVCode() {
        int len = code.length;
        Random ran = new Random();
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < vcodeLen; i++) {
            int index = ran.nextInt(len);
            sb.append(code[index]);
        }
        return sb.toString();
    }

    /**
     * 为验证码图片画一些干扰线
     * 
     * @param g
     */
    private void drawDisturbLine(Graphics g) {
        Random ran = new Random();
        for (int i = 0; i < disturbline; i++) {
            int x1 = ran.nextInt(width);
            int y1 = ran.nextInt(height);
            int x2 = ran.nextInt(width);
            int y2 = ran.nextInt(height);
            g.setColor(getRandomColor());
            // 画干扰线
            g.drawLine(x1, y1, x2, y2);
        }
    }

    /**
     * 获取一张旋转的图片
     * 
     * @param c 要画的字符
     * @return
     */
    private BufferedImage getRotateImage(char c) {
        BufferedImage rotateImage = new BufferedImage(height, height, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d = rotateImage.createGraphics();
        // 设置透明度为0
        g2d.setColor(new Color(255, 255, 255, 0));
        g2d.fillRect(0, 0, height, height);
        Random ran = new Random();
        g2d.setFont(new Font(fontNames[ran.nextInt(fontNames.length)], fontStyles[ran.nextInt(fontStyles.length)],
                fontsize));
        g2d.setColor(getRandomColor());
        double theta = getTheta();
        // 旋转图片
        g2d.rotate(theta, height / 2, height / 2);
        g2d.drawString(Character.toString(c), (height - fontsize) / 2, fontsize + 5);
        g2d.dispose();

        return rotateImage;
    }

    /**
     * @return 返回一个随机颜色
     */
    private Color getRandomColor() {
        Random ran = new Random();
        return new Color(ran.nextInt(220), ran.nextInt(220), ran.nextInt(220));
    }

    /**
     * @return 角度
     */
    private double getTheta() {
        return ((int) (Math.random() * 1000) % 2 == 0 ? -1 : 1) * Math.random();
    }

    /**
     * @return 验证码字符个数
     */
    public int getVcodeLen() {
        return vcodeLen;
    }

    /**
     * 设置验证码字符个数
     * 
     * @param vcodeLen
     */
    public void setVcodeLen(int vcodeLen) {
        this.width = (fontsize + 3) * vcodeLen + 10;
        this.vcodeLen = vcodeLen;
    }

    /**
     * @return 字体大小
     */
    public int getFontsize() {
        return fontsize;
    }

    /**
     * 设置字体大小
     * 
     * @param fontsize
     */
    public void setFontsize(int fontsize) {
        this.width = (fontsize + 3) * vcodeLen + 10;
        this.height = fontsize + 15;
        this.fontsize = fontsize;
    }

    /**
     * @return 图片宽度
     */
    public int getWidth() {
        return width;
    }

    /**
     * 设置图片宽度
     * 
     * @param width
     */
    public void setWidth(int width) {
        this.width = width;
    }

    /**
     * @return 图片高度
     */
    public int getHeight() {
        return height;
    }

    /**
     * 设置图片高度
     * 
     * @param height
     */
    public void setHeight(int height) {
        this.height = height;
    }

    /**
     * @return 干扰线条数
     */
    public int getDisturbline() {
        return disturbline;
    }

    /**
     * 设置干扰线条数
     * 
     * @param disturbline
     */
    public void setDisturbline(int disturbline) {
        this.disturbline = disturbline;
    }
}

controller.java：

@RequestMapping(value = "/get_cpacha", method = RequestMethod.GET)
    public void getCpacha(HttpServletRequest request,
            @RequestParam(value = "vl", defaultValue = "4", required = false) Integer vl,
            @RequestParam(value = "w", defaultValue = "98", required = false) Integer w,
            @RequestParam(value = "h", defaultValue = "33", required = false) Integer h, HttpServletResponse response) {
        // System.out.println("获取验证码");
        CpachaUtil cpachautil = new CpachaUtil(vl, w, h);
        String code = cpachautil.generatorVCode();
        request.getSession().setAttribute("loginCpacha", code);
        BufferedImage generatorVCodeImage = cpachautil.generatorVCodeImage(code, true);
        try {
            ImageIO.write(generatorVCodeImage, "gif", response.getOutputStream());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

前端：

<input class="input-text size-L" name="vcode" type="text" placeholder="请输入验证码" style="width: 200px;">
<img title="点击图片切换验证码" id="vcodeImg" src="get_cpacha?vl=4&w=110&h=40"></div>
</div>

<script type="text/javascript">
$(function(){
//点击图片切换验证码
$("#vcodeImg").click(function(){
this.src="get_cpacha?vl=4&w=152&h=40&t="+new Date().getTime();
});