验证码代码详解

验证码代码如下

package com.tshn.checkwork.controller.system;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
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.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/checkCodeAction/")
public class CheckCodeController  {

    @RequestMapping("service")
    public void service(HttpSession session, HttpServletResponse response) throws IOException {
        // 禁止缓存
        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 fontSize = 25;
        //int width = 100;
        int width = fontSize*4+10;
        int height = 41;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 创建BufferedImage类的对象
        Graphics g = image.getGraphics(); // 创建Graphics类的对象
        Graphics2D g2d = (Graphics2D) g; // 通过Graphics类的对象创建一个Graphics2D类的对象
        Random random = new Random(); // 实例化一个Random对象
        Font mFont = new Font("华文宋体", Font.BOLD, fontSize); // 通过Font构造字体
        //g.setColor(Color.WHITE); // 改变图形的当前颜色为随机生成的颜色
        g.setColor(getRandColor(200,250));
        g.fillRect(0, 0, width, height); // 绘制一个填色矩形

        // 画一条折线
        BasicStroke bs = new BasicStroke(1f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL); // 创建一个供画笔选择线条粗细的对象
        g2d.setStroke(bs); // 改变线条的粗细
        g.setColor(Color.DARK_GRAY); // 设置当前颜色为预定义颜色中的深灰色
        int[] xPoints = new int[3];
        int[] yPoints = new int[3];
        for (int j = 0; j < 3; j++) {
            xPoints[j] = random.nextInt(width - 1);
            yPoints[j] = random.nextInt(height - 1);
        }
        g.drawPolyline(xPoints, yPoints, 3);
        // 生成并输出随机的验证文字
        g.setFont(mFont);
        char[] chs = { '1', 'l', '0', 'O', 'o', 'L' };
        String sRand = "";
        int itmp = 0;
        for (int i = 0; i < 4; i++) {
            if (random.nextInt(2) == 1) {
                itmp = random.nextInt(26) + 65; // 生成A~Z的字母
            } else {
                itmp = random.nextInt(10) + 48; // 生成0~9的数字
            }
            boolean canAdd = true;
            for (char c : chs) {
                if (c == itmp) {
                    i = i - 1;
                    canAdd = false;
                }
            }
            if (canAdd == true) {
                char ctmp = (char) itmp;
                sRand += String.valueOf(ctmp);
                Color color = new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110));
                g.setColor(color);
                /**** 随机缩放文字并将文字旋转指定角度 **/
                // 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, 20 * i + fontSize/2, fontSize/2+1);
                // 缩放文字
                float scaleSize = random.nextFloat() + 0.8f;
                if (scaleSize >= 1.1f)
                    scaleSize = 1f;
                trans.scale(scaleSize, scaleSize);
                g2d_word.setTransform(trans);
                /************************/
                g.drawString(String.valueOf(ctmp), fontSize * i + 10, (height-fontSize)/2+10);
                //g.drawString(String.valueOf(ctmp), fontSize * i + 10, 10);
            }
        }
        
        // 将生成的验证码保存到Session中
        session.setAttribute("randCheckCode", sRand);
        g.dispose();
        ImageIO.write(image, "JPEG", response.getOutputStream());
    }
    
    /**
     * 论坛的回复帖验证码
     * @author zhanglei
     * @param session
     * @param response
     * @throws IOException
     */
    @RequestMapping("imgService")
    public void imgService(HttpSession session, HttpServletResponse response) throws IOException {
        // 禁止缓存
        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 fontSize = 25;
        //int width = 100;
        int width = fontSize*4;
        int height = 25;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 创建BufferedImage类的对象
        Graphics g = image.getGraphics(); // 创建Graphics类的对象
        Graphics2D g2d = (Graphics2D) g; // 通过Graphics类的对象创建一个Graphics2D类的对象
        Random random = new Random(); // 实例化一个Random对象
        Font mFont = new Font("华文宋体", Font.BOLD, fontSize); // 通过Font构造字体
        //g.setColor(Color.WHITE); // 改变图形的当前颜色为随机生成的颜色
        g.setColor(getRandColor(200,250));
        g.fillRect(0, 0, width, height); // 绘制一个填色矩形

        // 画一条折线
        BasicStroke bs = new BasicStroke(1f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL); // 创建一个供画笔选择线条粗细的对象
        g2d.setStroke(bs); // 改变线条的粗细
        g.setColor(Color.DARK_GRAY); // 设置当前颜色为预定义颜色中的深灰色
        int[] xPoints = new int[3];
        int[] yPoints = new int[3];
        for (int j = 0; j < 3; j++) {
            xPoints[j] = random.nextInt(width - 1);
            yPoints[j] = random.nextInt(height - 1);
        }
        g.drawPolyline(xPoints, yPoints, 3);
        // 生成并输出随机的验证文字
        g.setFont(mFont);
        char[] chs = { '1', 'l', '0', 'O', 'o', 'L' };
        String sRand = "";
        int itmp = 0;
        for (int i = 0; i < 4; i++) {
            if (random.nextInt(2) == 1) {
                itmp = random.nextInt(26) + 65; // 生成A~Z的字母
            } else {
                itmp = random.nextInt(10) + 48; // 生成0~9的数字
            }
            boolean canAdd = true;
            for (char c : chs) {
                if (c == itmp) {
                    i = i - 1;
                    canAdd = false;
                }
            }
            if (canAdd == true) {
                char ctmp = (char) itmp;
                sRand += String.valueOf(ctmp);
                Color color = new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110));
                g.setColor(color);
                /**** 随机缩放文字并将文字旋转指定角度 **/
                // 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, 20 * i + fontSize/2, fontSize/2+1);
                // 缩放文字
                float scaleSize = random.nextFloat() + 0.8f;
                if (scaleSize >= 1.1f)
                    scaleSize = 1f;
                trans.scale(scaleSize, scaleSize);
                g2d_word.setTransform(trans);
                /************************/
                g.drawString(String.valueOf(ctmp), fontSize * i + 10, (height-fontSize)/2+10);
                //g.drawString(String.valueOf(ctmp), fontSize * i + 10, 10);
            }
        }
        
        // 将生成的验证码保存到Session中 论坛回帖的验证码
        session.setAttribute("forumCheckCode", sRand);
        g.dispose();
        ImageIO.write(image, "JPEG", response.getOutputStream());
    }
    
    //设置背景颜色 add by yanght@2012-07-09
    public Color getRandColor(int fc,int bc){//给定范围获得随机颜色
       Random random = new Random();
       if(fc>255) fc=255;
       if(bc>255) bc=255;
       int r=fc+random.nextInt(bc-fc);
       int g=fc+random.nextInt(bc-fc);
       int b=fc+random.nextInt(bc-fc);
       return new Color(r,g,b);
    }

    @RequestMapping("service1.do")
    public String serv() {
        return "/check.jsp";
    }
}

js：

//验证码
            $("#fresh").click(function(){
                $("#img").attr("src","checkCodeAction/imgService.do?time="+new Date());
                /* $.ajax({
                    url:"checkCodeAction/service1.do",
                    type:"post",
                    datatype:"html",
                    success : function(data) {
                        $("#img_div").html('').append(data);
                    },
                    error : function() {
                        alert("ajax请求出错");
                    }
                }); */
            });

html：

<!-- 验证码 -->
                <span style="float: left; margin-left: 15px; margin-top: 8px;">验证码：
                    <input style=" 100px; height: 22px;"/>
                    <span id="img_div" ><img src="checkCodeAction/imgService.do" id="img" style=" 100px; height: 25px;"/></span>
                    <a id="fresh" href="javascript:void(0);">换一个</a>
                </span>