用tapestry4.0.x生成验证码

用tapestry4.0.x生成验证码 首先写一个从IEngineService派生的类，用来产生需要的验证图片 代码 package org.itrun.cnbrn.view.pageclass.system; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.IOException; import java.io.OutputStream; import java.util.Random; import javax.servlet.ServletContext; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.tapestry.IRequestCycle; import org.apache.tapestry.engine.IEngineService; import org.apache.tapestry.engine.ILink; import org.apache.tapestry.web.WebSession; import org.itrun.cnbrn.ConstantVar; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; public class ValidatorImageService implements IEngineService { Log logger=LogFactory.getLog(this.getClass()); private HttpServletResponse response; private ServletContext context; private String TYPE="jpeg"; public void setResponse(HttpServletResponse response){ this.response = response; } public void setContext(ServletContext context){ this.context=context; } public ILink getLink(boolean arg0, Object arg1) { return null; } public String getName() { return "validatorImage"; } public void service(IRequestCycle cycle) throws IOException { Random random = new Random(); StringBuffer sb=new StringBuffer(); for(int i=0;i<4;i++){ int x=random.nextInt(25); x+=65; sb.append(String.valueOf((char)x)); //sb.append(" "); } String validateString=sb.toString(); WebSession sess=cycle.getInfrastructure().getRequest().getSession(true); sess.setAttribute(ConstantVar.VALIDATOR_SESSION_KEY, validateString); //画布大小 int width = 60, height = 20; BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); // 以下填充背景颜色 g.setColor(Color.decode("#FFFFFF")); g.fillRect(0, 0, width, height); //随机产生其他元素，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 < 300; 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); } //字的颜色 g.setColor(Color.decode("#01556B")); //写的字的大小 g.setFont(new Font(null, Font.BOLD, 18)); //在画布上写字 g.drawString(validateString, 2, 16); g.dispose(); OutputStream os = response.getOutputStream(); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os); encoder.encode(image); os.close(); } private 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); } } ============================== hivemodule.xml文件增加以下内容 代码 <service-point id="ValidatorImageService" interface="org.apache.tapestry.engine.IEngineService"> invoke-factory> <construct class="org.itrun.cnbrn.view.pageclass.system.ValidatorImageService"/> /invoke-factory> </service-point> <contribution configuration-id="tapestry.services.ApplicationServices"> <service name="validatorImage" object="service:ValidatorImageService"/> </contribution> ============================ 在页面上调用 代码 <img jwcid="@Any" src="ognl:cnbrnContextPath+'/app?service=validatorImage'" />