下面给大家介绍一些生成图片验证码的工具方法：
一、生成随机字符串
public static void main(String args[]) { //产生随机字符串 System.out.println(TestImage.getCharArray(4)); } private static final char[] randChars = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'P', 'Q', 'M', 'N', 'Y', 'W' }; /** * 产生随机字符串 * * @param charSize * @return */ public static char[] getCharArray(int charSize) { char[] chars = new char[charSize]; Random ran = new Random(); for (int i = 0; i < charSize; i++) { chars[i] = randChars[ran.nextInt(randChars.length)]; } return chars; }
二、生成一张空白的图片
public static void main(String args[]) { BufferedImage img = createBlankVerifImage(4); File outputfile = new File("D:/blank.png"); try { ImageIO.write(img, "png", outputfile); }catch (Exception e) { e.printStackTrace(); } } /** * 产生一张空白的图片验证码 * * @param charCount 字符数 * @return */ public static BufferedImage createBlankVerifImage(int charCount) { return createBlankVerifImage(20 * charCount, 40); } /** * 产生一张空白的图片验证码 * * @param width 图片宽度 * @param height 图片高度 * @return */ public static BufferedImage createBlankVerifImage(int width, int height) { BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics graphic = image.getGraphics(); graphic.setColor(new Color(231, 231, 231));// Color.LIGHT_GRAY graphic.fillRect(0, 0, width, height); return image; }
三、生成有验证码的图片
public static void main(String args[]) { char[] chars = ImageTool.getCharArray(4); BufferedImage img = ImageTool.createRandVerifImage(chars);; File outputfile = new File("D:/save.png"); try { ImageIO.write(img, "png", outputfile); }catch (Exception e) { e.printStackTrace(); } } private static final char[] randChars = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'P', 'Q', 'M', 'N', 'Y', 'W' }; /** * 产生随机字符串 * * @param charSize * @return */ public static char[] getCharArray(int charSize) { char[] chars = new char[charSize]; Random ran = new Random(); for (int i = 0; i < charSize; i++) { chars[i] = randChars[ran.nextInt(randChars.length)]; } return chars; } /** * 产生一张图片验证码 * * @param chars 字符 * @return */ public static BufferedImage createRandVerifImage(char[] chars) { return createRandVerifImage(chars, 20 * chars.length, 40, 5, 30); } /** * 产生一张图片验证码 * * @param chars 字符 * @param width 图片宽度 * @param height 图片高度 * @param lineCount 干扰线数量 * @param fontSize 字体大小 * @return */ public static BufferedImage createRandVerifImage(char[] chars, int width, int height, int lineCount, int fontSize) { BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics graphic = image.getGraphics(); graphic.setColor(new Color(231, 231, 231));// Color.LIGHT_GRAY graphic.fillRect(0, 0, width, height); Random ran = new Random(); // 画随机字符 for (int i = 0; i < chars.length; i++) { graphic.setColor(new Color(ran.nextInt(156), ran.nextInt(156), ran.nextInt(156))); graphic.setFont(new Font(null, Font.BOLD + Font.ITALIC, fontSize)); graphic.drawString(chars[i] + "", (i * width - 10) / chars.length, (height - fontSize) / 2 + fontSize - 5); } // 画干扰线 for (int i = 0; i < lineCount; i++) { graphic.setColor(new Color(ran.nextInt(156), ran.nextInt(156), ran.nextInt(156))); graphic.drawLine(ran.nextInt(width), ran.nextInt(height), ran.nextInt(width), ran.nextInt(height)); } return image; }
四、生成电子签章
public static void main(String args[]) { try { BufferedImage img = TestImage.createSignImage("daishoucheng 代守诚"); File outputfile = new File("D:/save.png"); ImageIO.write(img, "png", outputfile); }catch (Exception e) { e.printStackTrace(); } } /** * 产生电子签名图片 * @param str * @return * @throws Exception */ public static BufferedImage createSignImage(String str) throws Exception { Font font=new Font("华文行楷", Font.BOLD, 100); int can=font.canDisplayUpTo(str); if (can>=0){ System.out.println("字符串【"+str+"】包含无法显示的文字，使用宋体"); font=new Font("宋体", Font.BOLD, 100); can=font.canDisplayUpTo(str); if (can>=0) { System.out.println("使用宋体后字符串【" + str + "】任然无法正常显示"); } } return createTextImage(str,font,Color.BLACK,str.length()*127,str.length()*127); } /** * 生成无背景的文字图片 * @param str 文字 * @param font 文字字体 * @param color 文字颜色 * @param width 图片宽度 * @param height 图片高度 * @return * @throws Exception */ public static BufferedImage createTextImage(String str, Font font,Color color,Integer width, Integer height) throws Exception { BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics2D g = image.createGraphics(); // g.setColor(Color.WHITE); // g.fillRect(0, 0, width, height); /** 增加下面的代码使得背景透明*/ image = g.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT); g.dispose(); g = image.createGraphics(); /** 背景透明代码结束*/ g.setColor(color); g.setFont(font); /** 用于获得垂直居中y */ g.setClip(0, 0, width, height); Rectangle clip = g.getClipBounds(); FontMetrics fm = g.getFontMetrics(font); int ascent = fm.getAscent(); int descent = fm.getDescent(); int y = (clip.height - (ascent + descent)) / 2 + ascent; /** 用于获得水平居中x */ int textWidth=fm.stringWidth(str); int x = (clip.width - textWidth )/ 2; g.drawString(str, x, y);// 画出字符串 g.dispose(); return image; }