[JSP] JSP随机验证图片如何制作

package icewee.image;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Line2D;
import java.awt.image.BufferedImage;
import java.util.Random;
public class TokenUtil {
  private static final String base = "23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefhijklmnpqrstuvwxyz";
  private static final int length = base.length();
  public static BufferedImage createTokenImage(int width, int height,
    String randomCode) {
  BufferedImage image = new BufferedImage(width, height,
    BufferedImage.TYPE_INT_RGB);
  Graphics2D g = image.createGraphics();
  Random random = new Random();
  g.setColor(new Color(230, 230, 250)); // 设置背景色
  g.fillRect(0, 0, width, height); // 填充背景
  g.setColor(Color.BLACK);
  // 绘制边缘
  g.drawRect(-1, -1, width + 1, height + 1);
  g.setColor(Color.GRAY);
  // 设置字体,随机选择字体,暂设置8种字体
  Font font = new Font((new String[] { "Arial", "Arial Black",
    "Arial Italic", "Courier New", "Courier New Bold Italic",
    "Courier New Italic", "Franklin Gothic Medium",
    "Franklin Gothic Medium Italic" })[random.nextInt(8)],
    Font.PLAIN, 30);
  // g.setStroke(new BasicStroke((float)(Math.random()),
  // BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL));
  g.setFont(font);
  // 定义字体颜色范围
  int red = random.nextInt(160), green = random.nextInt(50), blue = random
    .nextInt(50);
  // 定义一个无干扰线区间和一个起始位置
  int nor = random.nextInt(50), rsta = random.nextInt(131);
  // 绘制干扰正弦曲线 M:曲线平折度, D:Y轴常量 V:X轴焦距
  int M = random.nextInt(15) + 5, D = random.nextInt(23) + 15, V = random
    .nextInt(5) + 1;
  double x = 0.0;
  double y = M * Math.sin(Math.toRadians(V * x)) + D;
  double px, py;
  for (int i = 0; i < 131; i++) {
    px = x + 1;
    py = M * Math.sin(Math.toRadians(V * px)) + D;
    if (rsta < i && i < (rsta + nor))
    g.setColor(new Color(230, 230, 250));
    else
    g.setColor(new Color(red, green, blue));
    // 随机设置像素点宽带(线宽)
    g.setStroke(new BasicStroke((float) (Math.random() + 1.5f)));
    g.draw(new Line2D.Double(x, y, px, py));
    x = px;
    y = py;
  }
  char[] codes = randomCode.toCharArray();
  for (int i = 0; i < codes.length; i++) {
    // 旋转图形
    int degree = (random.nextInt(20) - 10) % 360;
    double ang = degree * 0.0174532925; // 将角度转为弧度
    g.rotate(ang, width / 2, height / 2);
    g.setColor(new Color(red, green, blue));
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
      RenderingHints.VALUE_ANTIALIAS_ON);
    int gr = random.nextInt(8);
    g.drawString(String.valueOf(codes[i]), 24 * i + 10 + gr, 38);
  }
  g.dispose();
  return image;
  }
  public static String createRandomCode(int size, int width, int height) {
  StringBuffer randomCode = new StringBuffer();
  for (int i = 0; i < size; i++) {
    Random random = new Random();
    int start = random.nextInt(length);
    String strRand = base.substring(start, start + 1);
    randomCode.append(strRand);
  }
  return randomCode.toString();
  }
}

<%@ page contentType="image/jpeg" pageEncoding="GBK"%>
<%@ page import="java.awt.image.BufferedImage" %>
<%@page import="javax.imageio.ImageIO" %>
<%@ page import="com.icesoft.image.TokenUtil" %>
<%
  //设置页面不缓存
  response.setHeader("Pragma", "No-cache");
  response.setHeader("Cache-Control", "no-cache");
  response.setDateHeader("Expires", 0);
  int width = 120, height = 50;
  String randomCode = TokenUtil.createRandomCode(4, width, height);
  System.out.println("生成的随机码：" + randomCode);
  BufferedImage image = TokenUtil.createTokenImage(width, height, randomCode);
  ImageIO.write(image, "JPEG", response.getOutputStream());
  response.flushBuffer();
  out.clear();
  out = pageContext.pushBody();
%>