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 javax.servlet.http.HttpSession; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; public class ImageServlet extends HttpServlet { private String number; private BufferedImage image; private void image() { image = new BufferedImage(60, 20, BufferedImage.TYPE_INT_RGB); Random r = new Random(); Graphics g = image.getGraphics(); g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255))); g.fillRect(0, 0, 60, 20); g.setColor(new Color(0, 0, 0)); number = String.valueOf(r.nextInt(99999)); g.drawString(number, 5, 15); } @Override public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { HttpSession session = request.getSession(); response.setContentType("image/jpeg"); image(); session.setAttribute("number", number); OutputStream os = response.getOutputStream(); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os); encoder.encode(image); } }