随机生成图形化验证码

package com.woniuxy.ajaxdemo.servlet;

import java.awt.*;

import java.awt.geom.*;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.util.Random;




import javax.imageio.ImageIO;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;


/**
 * 图片验证码生成
 * @author xumin
 *
 */

public class PictureCheckCodeServlet extends HttpServlet {




    // 获取随机颜色

    public Color getRandColor(int s, int e) {

        Random random = new Random();

        if (s > 255) s = 255;

        if (e > 255) e = 255;

        int r = s + random.nextInt(e - s); //随机生成RGB颜色中的r值

        int g = s + random.nextInt(e - s); //随机生成RGB颜色中的g值

        int b = s + random.nextInt(e - s); //随机生成RGB颜色中的b值

        return new Color(r, g, b);

    }




    public void service(HttpServletRequest request, HttpServletResponse response)

    throws ServletException, IOException {

        response.setHeader("Pragma", "No-cache");

        response.setHeader("Cache-Control", "No-cache");

        response.setDateHeader("Expires", 0);

        // 指定生成的响应是图片

        response.setContentType("image/jpeg");

        int width = 86;

        int height = 26;

        BufferedImage image = new BufferedImage(width, height,

                BufferedImage.TYPE_INT_RGB);

        Graphics g = image.getGraphics();

        Graphics2D g2d = (Graphics2D) g;

        Random random = new Random();

        Font mFont = new Font("黑体", Font.BOLD, 17);

        g.setColor(getRandColor(200, 250));

        g.fillRect(0, 0, width, height);

        g.setFont(mFont);

        g.setColor(getRandColor(180, 200));

        // 画随机的线条

        for (int i = 0; i < 100; i++) {

            int x = random.nextInt(width - 1);

            int y = random.nextInt(height - 1);

            int x1 = random.nextInt(6) + 1;

            int y1 = random.nextInt(12) + 1;

            BasicStroke bs = new BasicStroke(2f, BasicStroke.CAP_BUTT,

                    BasicStroke.JOIN_BEVEL);

            Line2D line = new Line2D.Double(x, y, x + x1, y + y1);

            g2d.setStroke(bs);

            g2d.draw(line);

        }

        String sRand = "";

        // 输出随机的验证文字

        String ctmp = "";

        int itmp = 0;

        for (int i = 0; i < 4; i++) {

            //random = new Random(new java.util.Date().getTime() + i);

            switch (random.nextInt(3)) {

            case 1:

                itmp = random.nextInt(26) + 65; // 生成A~Z的字母

                ctmp = String.valueOf((char) itmp);
                if (ctmp.equalsIgnoreCase("o")) {
                    ctmp = "A";
                }

                break;

            default:

                itmp = random.nextInt(10) + 48; // 生成0~9的数字

                ctmp = String.valueOf((char) itmp);
                if (ctmp.equalsIgnoreCase("0")) {
                    ctmp = "1";
                }

                break;

            }

            sRand += ctmp;

            Color color = new Color(20 + random.nextInt(110), 20 + random

                    .nextInt(110), 20 + random.nextInt(110));

            g.setColor(color);

            // 将文字旋转指定角度

            Graphics2D g2d_word = (Graphics2D) g;

            AffineTransform trans = new AffineTransform();

            trans.rotate(random.nextInt(45) * 3.14 / 180, 15 * i + 8, 7);

            // 缩放文字

            float scaleSize = random.nextFloat() +0.8f;

            if (scaleSize > 1f) scaleSize = 1f;

            trans.scale(scaleSize, scaleSize);

            g2d_word.setTransform(trans);

            g.drawString(ctmp, 15 * i + 18, 14);
        }

        // 将生成的验证码保存到Session中

        HttpSession session = request.getSession(true);

        session.setAttribute("randCheckCode", sRand);

        g.dispose();
        //System.out.println("randCheckCode:"+session.getAttribute("randCheckCode"));
        
        ImageIO.write(image, "JPEG", response.getOutputStream());

    }




}