struts2实现图片验证码

生成图片验证码的主要工具类方法为：

package com.yeting.fc.util;

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.util.Random;

import javax.imageio.ImageIO;
import javax.imageio.stream.ImageOutputStream;

public class ImageCodeUtil {
    /**
     * 生成随机验证码字符串
     * 
     * @return
     */
    public static String getImageCodeStr() {

        Random random = new Random();
        String code[] = { "A", "a", "B", "b", "C", "c", "D", "d", "E", "e",
                "F", "f", "G", "g", "H", "h", "I", "i", "J", "j", "K", "k",
                "L", "l", "M", "m", "N", "n", "O", "o", "P", "p", "Q", "q",
                "R", "r", "S", "s", "T", "t", "U", "u", "V", "v", "W", "w",
                "X", "x", "Y", "y", "Z", "z", "0", "1", "2", "3", "4", "5",
                "6", "7", "8", "9", "0", "1", "2", "3", "4", "5", "6", "7",
                "8", "9", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
                "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "1",
                "2", "3", "4", "5", "6", "7", "8", "9", "0", "1" };
        // 取随机产生的认证码(4位字符)
        StringBuffer codeStr = new StringBuffer("");
        for (int i = 0; i < 4; i++) {
            String cStr = code[random.nextInt(104)];
            codeStr.append(cStr);
        }
        return codeStr.toString();
    }

    /**
     * 生成带随机验证码的图片
     * 
     * @param codeStr
     * @return
     */
    public static BufferedImage createImage(String codeStr) {
        int width = 60, height = 20;
        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));
        // 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);
        }
        for (int i = 0; i < codeStr.length(); i++) {
            String cStr = codeStr.charAt(i) + "";
            g.setColor(new Color(random.nextInt(125), random.nextInt(125),
                    random.nextInt(125)));
            g.setFont(new Font("", Font.PLAIN, 20 + random.nextInt(5)));
            g.drawString(cStr, 15 * i + random.nextInt(5),
                    20 - random.nextInt(5));
        }
        g.dispose();
        return image;
    }

    /**
     * 返回验证码图片的流格式
     * 
     * @param codeStr
     * @return
     */
    public static ByteArrayInputStream getImageAsInputStream(String codeStr) {
        BufferedImage image = createImage(codeStr);
        return convertImageToStream(image);
    }
    
    private static ByteArrayInputStream convertImageToStream(BufferedImage image) {
        ByteArrayInputStream inputStream = null;
        ByteArrayOutputStream output = null;
        ImageOutputStream imageOut = null;
        try {
            output = new ByteArrayOutputStream();
            imageOut = ImageIO.createImageOutputStream(output);
            ImageIO.write(image, "JPEG", imageOut);
            inputStream = new ByteArrayInputStream(output.toByteArray());
        } catch (Exception e) {
            e.printStackTrace();
        } finally{
            try {
                if(imageOut!=null){
                    imageOut.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return inputStream;
    }

    /*
     * 给定范围获得随机颜色
     */
    private static Color getRandColor(int fc, int bc) {
        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);
    }

}

Action中主要代码为：

package com.yeting.fc.action;

import java.io.ByteArrayInputStream;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;
import com.yeting.fc.util.ImageCodeUtil;

public class ImageCodeAction extends ActionSupport{
    private static final long serialVersionUID = 1L;
    private ByteArrayInputStream inputStream;  
    public String getImageCode() throws Exception{
        //获取图片字符串
        String codeStr = ImageCodeUtil.getImageCodeStr();
        ActionContext.getContext().getSession().put("rand",codeStr);
        //System.out.println(codeStr);
        inputStream = ImageCodeUtil.getImageAsInputStream(codeStr);
        return SUCCESS;  
    }  
    
    public void setInputStream(ByteArrayInputStream inputStream) {  
        this.inputStream = inputStream;  
    }  
    public ByteArrayInputStream getInputStream() {  
        return inputStream;  
    }  
  
}

struts.xml文件中配置如下:

<!-- 验证码Action -->
   <action name="imageCode" class="imageCodeAction" method="getImageCode">
        <result type="stream">  
            <param name="contentType">image/jpeg</param>  
            <param name="inputName">inputStream</param>  
        </result> 
   </action>

登陆页面：主要代码。

<!--刷新请求，更换验证码内容。-->
<script type="text/javascript">
    function imageCode(){
        document.getElementById("imageCode").src="${pageContext.request.contextPath }/yeting/imageCode.action?st="+new Date();
    }
</script>



<!--验证码主要html文件-->

    验证码:<input style="50px;" type="text" name="imageCode"/>
          <a href="javascript:imageCode()">
                <img style="margin-top: 5px;" id="imageCode" src="${pageContext.request.contextPath }/yeting/imageCode.action"/>
          </a>
          <a href="javascript:imageCode()"><input style="35px;" type="button" value="更换"/></a>