package com.ws.frame.utils; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; import javax.imageio.ImageIO; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; /** * 随机验证码生成规则,用于页面防暴力破解 * @author YINGFU */ public class Captcha { public static final String SESSION_KEY = "CAPTCHA"; // session的属性名 private static final int WIDTH = 80; // 图片宽度 private static final int HEIGHT = 26; // 图片高度 private static final int LINESIZE = 8; // 图片干扰线数量 private static final int NUMBER = 4; // 产生字符数量 private static final int FONTSIZE = 18; // 图片文字大小 private static final int R = 255; private static final int G = 255; private static final int B = 255; private static final int DEFAULT_FONT_STYLE = Font.CENTER_BASELINE; //默认样式 private static final String DEFAULT_FONT_FAMILY = Font.SANS_SERIF; //默认字体 /** * 随机数产生池 */ private static final char[] CHARSPOOL = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' }; private Random random = new Random(); /** * 生成随机字符 * @return string */ private char randomCode(){ int length = CHARSPOOL.length; int num = random.nextInt(length); return CHARSPOOL[num]; } /** * 设置随机颜色的样式 * @return color */ private Color colorStyle(){ int r = random.nextInt(R); int g = random.nextInt(G); int b = random.nextInt(B); return new Color(r, g, b); } /** * 设置字体的基本样式 * @return font */ private Font fontStyle(){ //为linux服务器使用 System.setProperty("java.awt.headless", "true"); return new Font(DEFAULT_FONT_FAMILY, DEFAULT_FONT_STYLE, FONTSIZE); } /** * 设置文字的颜色 * @return */ private Color fontColorStyle(){ int r = random.nextInt(100); int g = random.nextInt(100); int b = random.nextInt(100); return new Color(r, g, b); } /** * 绘制随机数 * @param g * @param i * @return char */ private char drawRandomCode(Graphics g, int i){ g.setFont(fontStyle()); // g.setColor(colorStyle()); g.setColor(fontColorStyle()); char randomCode = randomCode(); g.translate(random.nextInt(3) , random.nextInt(3)); g.drawString(String.valueOf(randomCode), 13 * i, 16); return randomCode; } /** * 绘制干扰线 * @param g */ private void drawLine(Graphics g){ int x = random.nextInt(WIDTH); int y = random.nextInt(HEIGHT); int x2 = random.nextInt(WIDTH/2); int y2 = random.nextInt(HEIGHT/2); g.drawLine(x, y, x2, y2); } /** * 生成验证码 * @param session * @param response */ public void buildCaptcha(HttpSession session, HttpServletResponse response){ BufferedImage image = new BufferedImage(WIDTH, HEIGHT,BufferedImage.TYPE_INT_BGR); Graphics g = image.getGraphics(); g.fillRect(0, 0, WIDTH, HEIGHT); g.setFont(fontStyle()); g.setColor(colorStyle()); for(int i=0;i<LINESIZE;i++){ drawLine(g); } StringBuilder code = new StringBuilder(); for(int i=1; i<= NUMBER; i++){ code.append(drawRandomCode(g, i)); } session.removeAttribute(SESSION_KEY); session.setAttribute(SESSION_KEY, code.toString()); g.dispose(); try { ImageIO.write(image, "JPEG", response.getOutputStream()); } catch (IOException e) { e.printStackTrace(); } } }
图片中 字体 和 绘制图线的颜色随机生成。