随机验证码---支持大小写字母、数字、随机字体、文字大小(三)

    java随机产生验证码，可以随机生成数字、大写字母、小写字母。还可以随机生成文字字体、及大小。在图片上面可能字体都不不同、大小不等。

public class ValidCodeUtils {/** *  验证码生成工具类 *//********************************************************************* * 验证码宽度 */ public static int WIDTH = 60; /*** * 验证码高度 */ public static int HEIGHT = 20;  /********************************************************************** * 验证码背景颜色COLOR_FC_BG 应当小于COLOR_BC_BG */ public static int COLOR_FC_BG = 200; /*** * 验证码背景颜色COLOR_FC_BG 应当小于COLOR_BC_BG */ public static int COLOR_BC_BG = 250;  /********************************************************************** * 验证码背景干扰线颜色COLOR_FC_LINE 应当小于COLOR_BC_LINE */ public static int COLOR_FC_LINE = 160; /*** * 验证码背景干扰线颜色COLOR_FC_LINE 应当小于COLOR_BC_LINE */ public static int COLOR_BC_LINE = 200;  /*************************************************************************** * 验证码颜色COLOR_FC_CODE 应当小于COLOR_BC_CODE */ public static int COLOR_FC_CODE = 20; /*** * 验证码颜色COLOR_FC_CODE 应当小于COLOR_BC_CODE */ public static int COLOR_BC_CODE = 170;  /*************************************************************************** * 生成在指定范围内的颜色 * @param fc 范围fc color值 小于255 * @param bc 范围bc color值 小于255 * @return Color */ private static Color getRandColor(int fc, int bc) {     Random random = new Random();     if (fc < 0)     fc = 0;     if (bc < 0)     bc = 1;     if (fc > 255)     fc = 255;     if (bc > 255)     bc = 255;     if (bc == fc)      bc += 10;     int temp = 0;     if (bc < fc) {     temp = bc;     bc = fc;     fc = temp;     }     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); } /** * function:生成图片方法 * @param request HttpServletRequest * @param response HttpServletResponse * @return boolean * @throws Exception */ public static boolean getImage(HttpServletRequest request, HttpServletResponse response) throws Exception{     response.reset();     response.setContentType("image/jpeg");     // 设置页面不缓存     response.setHeader("Pragma", "No-cache");     response.setHeader("Cache-Control", "no-cache");     response.setDateHeader("Expires", 0);     // 在内存中创建图象          BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);     // 获取图形上下文     Graphics img = image.getGraphics();     // 生成随机类     Random random = new Random();     // 设定背景色     img.setColor(getRandColor(COLOR_FC_BG, COLOR_BC_BG));     img.fillRect(0, 0, WIDTH, HEIGHT);     // 设定字体     img.setFont(new Font("Times New Roman", Font.PLAIN, 18));     // 画边框     // g.setColor(new Color());     // g.drawRect(0,0,width-1,height-1);     // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到     img.setColor(getRandColor(COLOR_FC_LINE, COLOR_BC_LINE));     for (int i = 0; i < 155; i++) {  int x = random.nextInt(WIDTH);  int y = random.nextInt(HEIGHT);  int xl = random.nextInt(12);  int yl = random.nextInt(12);  img.drawLine(x, y, x + xl, y + yl);     }     // 取随机产生的认证码(4位数字)     String codeValue = "";     for (int i = 0; i < 4; i++) {  //String rand = String.valueOf(random.nextInt(10));  String rand = getRandomChar();  codeValue = codeValue.concat(rand);  img.setFont(getRandomFont());//随机字体  // 将认证码显示到图象中  img.setColor(getRandColor(COLOR_FC_CODE, COLOR_BC_CODE));  img.drawString(rand, 13 * i + 6, 16);     }     request.getSession().setAttribute("codeValue", codeValue);     // 图象生效     img.dispose();     // 输出图象到页面     return ImageIO.write(image, "JPEG", response.getOutputStream()); }  /** * 随机生成字符，含大写、小写、数字 * function: 功能 * @return */ public static String getRandomChar() {     int index = (int) Math.round(Math.random() * 2);     String randChar = "";     switch (index) {     case 0://大写字符     randChar = String.valueOf((char)Math.round(Math.random() * 25 + 65));     break;     case 1://小写字符     randChar = String.valueOf((char)Math.round(Math.random() * 25 + 97));     break;     default://数字     randChar = String.valueOf(Math.round(Math.random() * 9));     break;     }     return randChar; }  /** * function: 随机生成字体、文字大小 * @return */ public static Font getRandomFont() {     String[] fonts = {"Georgia", "Verdana", "Arial", "Tahoma", "Time News Roman", "Courier New", "Arial Black", "Quantzite"};     int fontIndex = (int)Math.round(Math.random() * (fonts.length - 1));     int fontSize = (int) Math.round(Math.random() * 4 + 16);     return new Font(fonts[fontIndex], Font.PLAIN, fontSize); } }