验证码代码

<%@ page contentType="image/jpeg; charset=utf-8" %>
<%@ page import="javax.imageio.ImageIO"%>
<%@ page import="java.awt.image.BufferedImage"%>
<%@ page import="java.awt.*"%>
<%@ page import="java.util.*"%>
<%@ page import="java.io.*"%>
<%!
  private static final String RANDOM_CHAR = "012345789";
  private Color getRandomColor(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);
  }
%>
<%
  response.setHeader("Pragma","No-cache");
  response.setHeader("Cache-Control","no-cache");
  response.setDateHeader("Expires", 0);

  int width = 60;
  int height = 20;
  BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
 
  Graphics g = image.getGraphics();
  g.setColor(getRandomColor(200,250));
  g.fillRect(0, 0, width, height);
  g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
  g.drawRect(0, 0, width-1, height-1);
 
  g.setColor(getRandomColor(160, 250));
  Random random = new Random();
  for(int i = 0; i < 155; i++){
    int x = random.nextInt(width);
    int y = random.nextInt(height);
    int x1 = random.nextInt(12);
    int y1 = random.nextInt(12);
    g.drawLine(x, y, x+x1, y+y1);
  }
 
  String randomStr="";
  for(int i=0;i<4;i++){
    int randomNum = random.nextInt(9);
    String rand = RANDOM_CHAR.substring(randomNum, randomNum + 1);
    randomStr += rand;
    g.setColor(new Color(20 + random.nextInt(110),
                 20 + random.nextInt(110),
                 20 + random.nextInt(110)));
    g.drawString(rand, 13 * i + 6, 16);
  }
  g.dispose();
  ServletOutputStream output = response.getOutputStream();
  session.setAttribute("ValidCode",randomStr);
  ImageIO.write(image, "JPEG", output);
  out.clear();
  out = pageContext.pushBody();
%>