package cn.response; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; import javax.imageio.ImageIO; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @SuppressWarnings("serial") public class validatePicture extends HttpServlet {  public void doGet(HttpServletRequest request, HttpServletResponse response)    throws ServletException, IOException {   try {    validateimage(request, response);   } catch (Exception e) {    e.printStackTrace();   }  }  public void doPost(HttpServletRequest request, HttpServletResponse response)    throws ServletException, IOException {   doGet(request, response);  }  public static final int WIDTH = 120;  public static final int HEIGHT = 25;  public void validateimage(HttpServletRequest request,    HttpServletResponse response) throws Exception {   BufferedImage bi = new BufferedImage(WIDTH, HEIGHT,     BufferedImage.TYPE_INT_RGB);// 在内存中构建一幅图象   Graphics g = bi.getGraphics();   setBackGround(g);// 设置背景色   setBorder(g);// 设置边框   drawRandomLine(g);// 画干扰线   String random = drawRandomNum((Graphics2D) g);// 写随机数   request.getSession().setAttribute("random", random);   //request.getSession(false);   response.setContentType("image/jpeg");   // 设置不要缓存   response.setDateHeader("expries", -1);   response.setHeader("Cache-Control", "no-cache");   ImageIO.write(bi, "jpg", response.getOutputStream());  }  private String drawRandomNum(Graphics2D g) {   g.setColor(Color.RED);   g.setFont(new Font("宋体", Font.BOLD, 20));   // [\u4e00-\u9fa5]中文数字区间   String base = "\u4e00\u4f00\u5e00\u4e50\u4e89\u4f10\u4e09";   StringBuffer sb = new StringBuffer();   int x = 5;   for (int i = 0; i < 4; i++) {    int degree = new Random().nextInt() % 30;    String ch = base.charAt(new Random().nextInt(base.length())) + "";    sb.append(ch);    g.rotate(degree * Math.PI / 180, x, 20);    g.drawString(ch, x, 20);    g.rotate(-degree * Math.PI / 180, x, 20);    x = x + 30;   }   System.out.println(sb.toString());   return sb.toString();  }  private void drawRandomLine(Graphics g) {   g.setColor(Color.GREEN);   for (int i = 0; i < 3; i++) {    int x1 = new Random().nextInt(WIDTH);    int y1 = new Random().nextInt(HEIGHT);    int x2 = new Random().nextInt(WIDTH);    int y2 = new Random().nextInt(HEIGHT);    g.drawLine(x1, y1, x2, y2);   }  }  private void setBorder(Graphics g) {   g.setColor(Color.BLUE);   g.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);  }  private void setBackGround(Graphics g) {   g.setColor(Color.WHITE);   g.fillRect(0, 0, WIDTH, HEIGHT);  } }