jsf实现验证码功能

http://stenlylee.iteye.com/blog/317179 学习这位朋友的这篇文章，我在详细写下实现步骤。

 

首先我的例子环境是hibernate+spring+jsf。

 

再次，backbean上的代码稍微修改一下，如下

public class ImageData implements Serializable {

	private static final long serialVersionUID = -8161565799237268271L;
	private BufferedImage image;
	Integer width = 60;
	Integer height = 20;
	Color bankgroud = new Color(0xFFFFFF);
	Color drawColor = new Color(0x000000);
	Font textFont = new Font("Comic Sans ms", Font.PLAIN, 18);
	String str = "0,a,2,x,e,5,j,7,l,9,1,b,c,d,4,f,g,h,i,6,k,8,m,n,o,p,q,r,s,t,u,v,w,3,y,z";
	Random random = new Random();

	public void paint(OutputStream out, Object data) throws IOException {
		if (data instanceof ImageData) {
			// create the image
			image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
			Graphics graphics = image.getGraphics();
			graphics.setColor(bankgroud);
			graphics.fillRect(0, 0, width, height);
			graphics.setColor(drawColor);
			graphics.drawRect(0, 0, width - 1, height - 1);
			graphics.setFont(textFont);
			// 绘制干扰线
			for (int i = 0; i < 160; i++) {
				int x = random.nextInt(width);
				int y = random.nextInt(height);
				int xl = random.nextInt(12);
				int yl = random.nextInt(12);
				graphics.setColor(getRandColor(100, 250));
				graphics.drawLine(x, y, x + xl, y + yl);
			}
			// 绘制验证码
			graphics.setColor(drawColor);
			String code = "";
			String[] array = str.split(",");
			for (int i = 0; i < 4; i++) {
				String rand = array[random.nextInt(36)];
				code += rand;
				graphics.drawString(rand, 13 * i + 6, 16);
			}
			/**
			 * 这里和上面那位朋友用的有点不一样，我没有自己去写facesUtil这个类，
			 * 我这里直接把随机生成的代码保存session
			 */
			FacesContext facesContext = FacesContext.getCurrentInstance();
			try {
				HttpSession session = (HttpSession) facesContext
						.getExternalContext().getSession(true);
				session.setAttribute("code", code);
			} catch (Exception e) {
				e.printStackTrace();
			}

			// FacesUtil.getSession().setAttribute("code", code);
			graphics.dispose();
		}
		ImageIO.write(image, "JPEG", out);
	}

	private 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);
	}

}

  然后，这bean要写进jsf的配置文件里面

 

<managed-bean>      
		<managed-bean-name>validateCodeImageData</managed-bean-name>  
   	<managed-bean-class>  
       com.express.bb.ImageData   
   	</managed-bean-class>  
   		<managed-bean-scope>request</managed-bean-scope>  
	</managed-bean> 

 

然后要把生成的随机码显示到jsf页面 这里需要用到richfaces的标签显示，可以去http://www.jboss.org/jbossrichfaces/downloads/这里下包(我用的3.1版本的)，当把包导进工程之后，

在web.xml文件中添加以下代码

<!--                 配置richfaces              -->
	<context-param>
	<param-name>org.richfaces.SKIN</param-name>
	<param-value>blueSky</param-value>
	</context-param>
	<filter>
	<display-name>RichFaces Filter</display-name>
	<filter-name>richfaces</filter-name>
	<filter-class>org.ajax4jsf.Filter</filter-class>
	</filter>
	<filter-mapping>
	<filter-name>richfaces</filter-name>
	<servlet-name>Faces Servlet</servlet-name>
	<dispatcher>REQUEST</dispatcher>
	<dispatcher>FORWARD</dispatcher>
	<dispatcher>INCLUDE</dispatcher>
	</filter-mapping>

 最后，就可以在你要显示 的页面加上

<%@ taglib uri="http://richfaces.org/a4j" prefix="a4j"%>
<%@ taglib uri="http://richfaces.org/rich" prefix="rich"%>


<a4j:mediaOutput element="img" cacheable="flase" session="false"
				rendered="true" createContent="#{validateCodeImageData.paint}"
				value="#{validateCodeImageData}" mimeType="image/jpeg" />

 

到这里就可以运行一下工程看效果了。

good luck ！！