| 文件名：Image.java ================================================================== /* * Created on 2004-8-4 * * To change the template for this generated file go to * Window>Preferences>Java>Code Generation>Code and Comments */ package myclass.test; import java.awt.*; import java.awt.image.*; import java.util.*; /** * @author * * To change the template for this generated type comment go to * Window>Preferences>Java>Code Generation>Code and Comments */ public class Image { public String sRand=""; public 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); } public BufferedImage creatImage(){ // 在内存中创建图象 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)); //画边框 //g.setColor(new Color()); //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<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); } // 取随机产生的认证码(4位数字) //String rand = request.getParameter("rand"); //rand = rand.substring(0,rand.indexOf(".")); for (int i=0;i<4;i ){ String rand=String.valueOf(random.nextInt(10)); sRand =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); } // 图象生效 g.dispose(); return image; } } ====================================================================== image.jsp(对bean的引用) <%@ page contentType="image/jpeg" import="javax.imageio.*" %> <jsp:useBean id="image" scope="session" class="myclass.test.Image"/> <% //设置页面不缓存 response.setHeader("Pragma","No-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires", 0); // 将认证码存入SESSION session.setAttribute("rand",image.sRand); // 输出图象到页面 ImageIO.write(image.creatImage(), "JPEG", response.getOutputStream()); %> |
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