myeclipse
新建一个servelet 名字叫ImageRandServlet
在doget方法中填写如下代码
ImageRandServlet 类的代码如下：import java.awt.Color;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;import java.util.Random;import java.awt.Font; import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class ImageRandServlet extends HttpServlet { private static final String CONTENT_TYPE = 'image/jpeg'; //Initialize global variables public void init() throws ServletException { } //Process the HTTP Get request public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { response.setHeader('Pragma', 'No-cache'); response.setHeader('Cache-Control', 'no-cache'); response.setDateHeader('Expires', 0); int width = 60, height = 20; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); OutputStream os = response.getOutputStream(); Graphics g = image.getGraphics(); Random random = new Random(); g.setColor(getRandColor(200, 250)); g.fillRect(0, 0, width, height); g.setFont(new Font('Arial', Font.PLAIN, 18)); 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); } String sRand = ''; for (int j = 0; j < 4; j++) { String rand = String.valueOf(random.nextInt(10)); sRand += rand; g.setColor(new Color(20 + random.nextInt(110), 20 + random .nextInt(110), 20 + random.nextInt(110))); g.drawString(rand, 13 * j + 6, 16); } request.getSession().setAttribute('rand', sRand); g.dispose(); ImageIO.write(image, 'JPEG', os); os.flush(); os.close(); os = null; response.flushBuffer(); // out.clear(); // out = pageContext.pushBody(); } catch (IllegalStateException e) { e.printStackTrace(); } } //Process the HTTP Post request public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } //Clean up resources public void destroy() { } public 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); }}
新建test.jsp页面，此页面是来现实验证码的界面
在
之间添加如下代码：jsp代码如下：<%@ page language='java' import='java.util.*' pageEncoding='utf-8'%><%String path = request.getContextPath();String basePath = request.getScheme()+'://'+request.getServerName()+':'+request.getServerPort()+path+'/';%>
在WEB-INF目录下找到web.xml 在
运行程序，结果如下