servlet随机验证码

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 javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; public class ImageServlet extends HttpServlet { public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("image/jpeg"); BufferedImage image = getImage(60, 20, BufferedImage.TYPE_INT_BGR); image(image); JPEGImageEncoder encoder = encoder(response.getOutputStream()); encoder.encode(image); } private BufferedImage getImage(int... is) { return new BufferedImage(is[0], is[1], is[2]); } private JPEGImageEncoder encoder(OutputStream stream) { return JPEGCodec.createJPEGEncoder(stream); } private void image(BufferedImage image) { Graphics graphics = image.getGraphics(); Random r = new Random(); graphics.setColor(new Color(r.nextInt(255), r.nextInt(255), r .nextInt(255))); graphics.fillRect(0, 0, 60, 20); graphics.setColor(new Color(0, 0, 0)); String number = String.valueOf(r.nextInt(99999)); graphics.drawString(number, 5, 15); } }
<?xml version="1.0" encoding="GB18030"?> <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <servlet> <servlet-name>ImageServlet</servlet-name> <servlet-class>ImageServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ImageServlet</servlet-name> <url-pattern>/image</url-pattern> </servlet-mapping> </web-app>