Servlet 验证码
import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.OutputStream;import java.util.Random;import javax.imageio.ImageIO;import javax.imageio.stream.ImageOutputStream;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * 能动态产生图形，并且输出图形的Servlet ** @author WilliamRong * @version 1.0 **/public class GenerateImageServlet extends HttpServlet {private static final long serialVersionUID = 760480418450678827L;/** * 产生的图像的宽度，单位为像素。 */private final static int WIDTH = 260;/** * 产生的图像的高度，单位为像素。 */private final static int HEIGHT = 60;public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {// 设置输出的内容的类型为jpeg图像response.setContentType("image/jpeg");OutputStream os = response.getOutputStream();createImage(os);os.close();}/** * 绘制输出整个图形 */public void createImage(OutputStream os) throws IOException {// 创建一个BufferedIamge对象BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);// 获取的Graphics2D对象，通过这个对象完成绘图Graphics2D g = image.createGraphics();// 绘制背景图g.setColor(Color.white);g.fillRect(0, 0, WIDTH, HEIGHT);// 画边框g.setColor(Color.black);g.drawRect(0, 0, WIDTH - 1, HEIGHT - 1);// 设定字体g.setFont(new Font("Times New Roman", Font.PLAIN, 60));// 生成随机类Random random = new Random();// 取随机产生的6位数字for (int i = 0; i < 6; i++) {String rand = String.valueOf(random.nextInt(10));// 将随机产生的数字显示到图象中g.drawString(rand, 40 * i + 20, 50);}// 生成图像的输出流ImageOutputStream ios = ImageIO.createImageOutputStream(os);ImageIO.write(image, "jpeg", ios);ios.close();}}
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