<servlet> <servlet-name>image</servlet-name> <servlet-class>org.test.web.AuthImage</servlet-class> </servlet> <servlet-mapping> <servlet-name>image</servlet-name> <url-pattern>/authImage</url-pattern> </servlet-mapping>
其servlet源代码:
public class AuthImage extends HttpServlet { private static final String CONTENT_TYPE = "text/html; charset=gb2312"; //设置字母的大小,大小 private Font mFont = new Font("Times New Roman", Font.PLAIN, 17); public void init() throws ServletException { super.init(); } 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); } public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setHeader("Pragma","No-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires", 0); //表明生成的响应是图片 response.setContentType("image/jpeg"); int width=100, height=18; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics g = image.getGraphics(); Random random = new Random(); g.setColor(getRandColor(200,250)); g.fillRect(1, 1, width-1, height-1); g.setColor(new Color(102,102,102)); g.drawRect(0, 0, width-1, height-1); g.setFont(mFont); g.setColor(getRandColor(160,200)); //画随机线 for (int i=0;i<155;i++) { int x = random.nextInt(width - 1); int y = random.nextInt(height - 1); int xl = random.nextInt(6) + 1; int yl = random.nextInt(12) + 1; g.drawLine(x,y,x + xl,y + yl); } //从另一方向画随机线 for (int i = 0;i < 70;i++) { int x = random.nextInt(width - 1); int y = random.nextInt(height - 1); int xl = random.nextInt(12) + 1; int yl = random.nextInt(6) + 1; g.drawLine(x,y,x - xl,y - yl); } //生成随机数,并将随机数字转换为字母 String sRand=""; for (int i=0;i<6;i++) { int itmp = random.nextInt(26) + 65; char ctmp = (char)itmp; sRand += String.valueOf(ctmp); g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110))); g.drawString(String.valueOf(ctmp),15*i+10,16); } HttpSession session = request.getSession(true); session.setAttribute("rand",sRand); g.dispose(); ImageIO.write(image, "JPEG", response.getOutputStream()); } public void destroy() { } }
怎样用:
在页面显示随机图片,可在JSP页面中增加如下代码即可:
<img src="authImage">
转至:http://menjoy.iteye.com