struts2验证码实现

话不多说直接上代码！

jsp中验证码源文件：

<a id="ptr" href="javascript:;"><img height="27px"  alt="换一张" src="<%=request.getContextPath() %>/getVerifyCode" id="prtImg"/></a>

 

struts配置文件：

<!-- 验证码 -->
<action name="getVerifyCode" class="verifyCodeAction" method="getVerifyCode" >
	<result type="stream">  
        	<param name="contentType">image/jpeg</param>  
        	<param name="inputName">inputStream</param>  
        </result>  
</action>

 

java代码：

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.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;

/**
 * 类描述：验证码生成
 * 
 * @author ming.li
 * @time 2011-4-21 上午11:30:45
 */
public class VerifyCodeAction extends ActionSupport {

	/** 版本号 */
	private static final long serialVersionUID = 5090480110300205197L;
	/** 文件输入流 */
	private ByteArrayInputStream inputStream;
	/** 随机数 */
	private static final Random random = new Random();
	/** MD5加密 */
	private static final MD5 md5 = new MD5();
	/** 文本类型 */
	private static final String CONTENT_TYPE = "image/jpeg";
	/** 画布宽度 */
	private static int imgWidth = 60;
	/** 画布高度 */
	private static int imgHeight = 20;
	/** 验证码位数 */
	private static int imgCount = 4;

	/**
	 * 
	 * 方法描述：获取验证码
	 * 
	 * @author ming.li
	 * @time 2011-4-25 下午01:56:19
	 * 
	 * @return
	 */
	public String getVerifyCode() {
		try {
			this.inputStream = generateImage();
		} catch (IOException e) {
			e.printStackTrace();
		}

		return SUCCESS;
	}

	/**
	 * 
	 * 方法描述：输出验证码图片
	 * 
	 * @author ming.li
	 * @time 2011-5-30 下午01:44:04
	 * 
	 * @return
	 */
	public ByteArrayInputStream getInputStream() {
		return inputStream;
	}

	/**
	 * 
	 * 方法描述：输入验证码文件到流中
	 * 
	 * @author ming.li
	 * @time 2011-4-25 下午01:56:29
	 * 
	 * @return
	 * @throws IOException
	 */
	private ByteArrayInputStream generateImage() throws IOException {

		HttpServletResponse response = ServletActionContext.getResponse();
		HttpServletRequest request = ServletActionContext.getRequest();

		response.setContentType(CONTENT_TYPE);
		response.setHeader("Pragma", "No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires", 0);
		// PrintWriter out = response.getWriter();
		int width = imgWidth, height = imgHeight;
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		// 获取图形上下文
		Graphics g = image.getGraphics();
		// 设定背景色
		g.setColor(getRandColor(200, 250));
		g.setColor(new Color(255, 255, 255));
		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(getRandColor(200, 250));
		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 < 10; i++) {
			int x = random.nextInt(width);
			int y = random.nextInt(height);
			int xl = random.nextInt(100);
			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)
		StringBuffer randSB = new StringBuffer();
		for (int i = 0; i < imgCount; i++) {
			String rand = String.valueOf(random.nextInt(10));
			randSB.append(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, 13 * i + 6, 16);
		}

		// 将认证码存入SESSION
		String randMD5 = md5.getMD5ofStr(randSB.toString());
		request.getSession().setAttribute(Constants.VERFIY_CODE, randMD5);
		// 图象生效
		g.dispose();
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		ImageIO.write(image, "JPEG", bos);
		byte[] buf = bos.toByteArray();

		return new ByteArrayInputStream(buf);
	}

	/**
	 * 
	 * 方法描述：给定范围获得随机颜色
	 * 
	 * @author ming.li
	 * @time 2011-4-25 下午01:56:55
	 * 
	 * @param fc
	 * @param bc
	 * @return
	 */
	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);
	}

}