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="width: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="width:35px;" type="button" value="更换"/></a>