JSP中驗(yàn)證碼的使用

1、JSP中驗(yàn)證碼的使用 import javax.servlet.*;import javax.servlet.http.*;import java.io.*;import java.util.*;import java.awt.image.*;import java.awt.*;import com.sun.image.codec.jpeg.*;/* 在Web.xml中布署： CodePicServlet com.liuxu.servlet.CodePicServlet CodePicServlet /verifycode * 在JSP中寫上：* 驗(yàn)證碼 src=/模塊名/verifycode

2、 /* 在調(diào)用時，運(yùn)行String random = (String session.getAttribute(verifyCode;* 得到產(chǎn)生的驗(yàn)證碼*/public class CodePicServlet extends HttpServlet /改成Servlet，就重寫service方法就不會出現(xiàn)IllegalStateException異常了，不要寫在JSP中 protected void service(HttpServletRequest request, HttpServletResponse response throws ServletException, IOExce

3、ption String chose = 0123456789; /abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ Random rand = new Random(; HttpSession session = request.getSession(true; / 設(shè)置顯示內(nèi)容 response.setContentType(image/jpeg; /設(shè)置頁面不緩存 response.addHeader(pragma, NO-cache; response.addHeader(Cache-Control, no-cache; resp

4、onse.addDateHeader(Expries, 0; / 在內(nèi)存中創(chuàng)建圖象 int width = 65, height = 20; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB; / 獲取圖形上下文 Graphics g = image.getGraphics(; /以下填充背景顏色 g.setColor(new Color(51, 102, 255; g.fillRect(0, 0, width, height; /畫邊框 / g.setColor(Color.BL

5、ACK; / g.drawRect(0, 0, width - 1, height - 1; / 隨機(jī)產(chǎn)生很多條干擾線，使圖象中的認(rèn)證碼不易被其它程序探測到 for (int i = 0; i 30; i+ g.setColor(getRandColor(100, 150; int x = rand.nextInt(width; int y = rand.nextInt(height; int xl = rand.nextInt(10; int yl = rand.nextInt(10; g.drawLine(x, y, x + xl, y + yl; /設(shè)置字體 g.setFont(new Font(Times New Roman, Font.BOLD + Font.ITALIC, 16; /設(shè)置字體顏色 g.setColor(Color.WHITE; / 取隨機(jī)產(chǎn)生的認(rèn)證碼(4位數(shù)字 String sRand = ; for (int i = 0; i 255 beginColor = 255; if (endColor 255 endColor = 255; int r = beginColor + random.nextInt(endColor - beginColor; int g = beginColor + random.nextInt(endColor - beg