java 生成验证码图片

图片对象

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class VImage extends HttpServlet {
    /**
     * serialVersionUID
     */
    private static final long serialVersionUID = 1L;
    
    private ByteArrayInputStream image;

    public ByteArrayInputStream getImage() {
        return image;
    }

    public void setImage(ByteArrayInputStream image) {
        this.image = image;
    }

    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);
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        // 设置页面不缓存

        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);

        // 在内存中创建图象
        int width = 100, height = 30;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);

        // 获取图形上下文

        Graphics g = image.getGraphics();

        // 生成随机类

        Random random = new Random();

        // 设定背景色

        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);

        // 设定字体
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

        // 画边框

        // g.setColor(new Color());
        // g.drawRect(0,0,width-1,height-1);

        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到

        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }

        // 取随机产生的认证码(4位数字)
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            String rand = String.valueOf(random.nextInt(10));
            sRand += rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20 + random.nextInt(110), 20 + random
                    .nextInt(110), 20 + random.nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成

            g.drawString(rand, 25 * i + 6, 22);    //验证码在图片中的显示位置
        }

        //将认证码存入SESSION
        request.getSession().setAttribute("rand", sRand);

        // 图象生效
        g.dispose();
        
        ByteArrayInputStream input = null;
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        try {
            ImageOutputStream imageOut = ImageIO.createImageOutputStream(output);
            // 输出图象到页面

            ImageIO.write(image, "JPEG", imageOut);
            imageOut.close();
            input = new ByteArrayInputStream(output.toByteArray());
        } catch (Exception e) {
            //not handle
        }

        this.image = input;
    }
}

相关action

import java.io.ByteArrayInputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import org.apache.log4j.Logger;
import org.apache.struts2.ServletActionContext;

import com.keertech.base.action.AbstractAction;
import com.keertech.util.VImage;


public class ImageAction extends AbstractAction {
    /**
     * serialVersionUID
     */
    private static final long serialVersionUID = 1L;
    
    /**
     * log
     */
    private Logger log = Logger.getLogger(this.getClass().getName());
    
    private ByteArrayInputStream inputStream;  

    public String getValCode(){
        VImage v=new VImage();
        try {
            v.doGet(ServletActionContext.getRequest(), ServletActionContext.getResponse());
            this.setInputStream(v.getImage());
        } catch (ServletException e) {
            log.info(e.getMessage());
        } catch (IOException e) {
            log.info(e.getMessage());
        }
        
        return SUCCESS;
    }
    
    public ByteArrayInputStream getInputStream() {
        return inputStream;
    }
    
    public void setInputStream(ByteArrayInputStream inputStream) {
        this.inputStream = inputStream;
    }
}

struts配置

<action name="rand" class="com.keertech.web.action.ImageAction"
            method="getValCode">
            <result type="stream">
                <param name="contentType">image/jpeg</param>
                <param name="inputName">inputStream</param>
            </result>
        </action>

js

function changeValidateCode(obj) {
            var myDate = new Date();
            obj.src = "webbase/rand.action?date=" + myDate;
        }

html

<img style="display: block;float: left;cursor:hand;" src="rand.action" id="valImg" onclick="changeValidateCode(this)" title="更换验证码" />