页面上输入验证码是比较常见的一个功能,实现起来也很简单.给大家写一个简单的生成验证码的示例程序,需要的朋友可以借鉴一下.
闲话少续,直接上代码.代码中的注释很详细.
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package com.SM_test.utils; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.util.Arrays; import java.util.Random; import javax.imageio.ImageIO; public class VerifyCodeUtils{ //使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符 public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ"; private static Random random = new Random(); /** * 使用系统默认字符源生成验证码 * @param verifySize 验证码长度 * @return */ public static String generateVerifyCode(int verifySize){ return generateVerifyCode(verifySize, VERIFY_CODES); } /** * 使用指定源生成验证码 * @param verifySize 验证码长度 * @param sources 验证码字符源 * @return */ public static String generateVerifyCode(int verifySize, String sources){ if(sources == null || sources.length() == 0){ sources = VERIFY_CODES; } int codesLen = sources.length(); Random rand = new Random(System.currentTimeMillis()); StringBuilder verifyCode = new StringBuilder(verifySize); for(int i = 0; i < verifySize; i++){ verifyCode.append(sources.charAt(rand.nextInt(codesLen-1))); } return verifyCode.toString(); } /** * 生成随机验证码文件,并返回验证码值 * @param w * @param h * @param outputFile * @param verifySize * @return * @throws IOException */ public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException{ String verifyCode = generateVerifyCode(verifySize); outputImage(w, h, outputFile, verifyCode); return verifyCode; } /** * 输出随机验证码图片流,并返回验证码值 * @param w * @param h * @param os * @param verifySize * @return * @throws IOException */ public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException{ String verifyCode = generateVerifyCode(verifySize); outputImage(w, h, os, verifyCode); return verifyCode; } /** * 生成指定验证码图像文件 * @param w * @param h * @param outputFile * @param code * @throws IOException */ public static void outputImage(int w, int h, File outputFile, String code) throws IOException{ if(outputFile == null){ return; } File dir = outputFile.getParentFile(); if(!dir.exists()){ dir.mkdirs(); } try{ outputFile.createNewFile(); FileOutputStream fos = new FileOutputStream(outputFile); outputImage(w, h, fos, code); fos.close(); } catch(IOException e){ throw e; } } /** * 输出指定验证码图片流 * @param w * @param h * @param os * @param code * @throws IOException */ public static void outputImage(int w, int h, OutputStream os, String code) throws IOException{ int verifySize = code.length(); BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Random rand = new Random(); Graphics2D g2 = image.createGraphics(); g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON); Color[] colors = new Color[5]; Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN, Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE, Color.PINK, Color.YELLOW }; float[] fractions = new float[colors.length]; for(int i = 0; i < colors.length; i++){ colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)]; fractions[i] = rand.nextFloat(); } Arrays.sort(fractions); g2.setColor(Color.GRAY);// 设置边框色 g2.fillRect(0, 0, w, h); Color c = getRandColor(200, 255); g2.setColor(c);// 设置背景色 g2.fillRect(0, 2, w, h-4); //绘制干扰线 Random random = new Random(); g2.setColor(getRandColor(50, 255));// 设置线条的颜色 for (int i = 0; i < 20; i++) { int x = random.nextInt(w - 1); int y = random.nextInt(h - 1); int xl = random.nextInt(6) + 1; int yl = random.nextInt(12) + 1; g2.drawLine(x, y, x + xl + 40, y + yl + 20); } // 添加噪点 float yawpRate = 0.05f;// 噪声率 int area = (int) (yawpRate * w * h); for (int i = 0; i < area; i++) { int x = random.nextInt(w); int y = random.nextInt(h); int rgb = getRandomIntColor(); image.setRGB(x, y, rgb); } shear(g2, w, h, c);// 使图片扭曲 // g2.setColor(getRandColor(100, 160)); int fontSize = h-4; Font font = new Font("Algerian", Font.ITALIC, fontSize); g2.setFont(font); char[] chars = code.toCharArray(); for(int i = 0; i < verifySize; i++){ AffineTransform affine = new AffineTransform(); affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2); g2.setTransform(affine); g2.setColor(getRandColor(100, 160)); g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h-(h - (int)(fontSize*0.75))/2); } g2.dispose(); ImageIO.write(image, "jpg", os); } private static Color getRandColor(int fc, int bc) { 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); } private static int getRandomIntColor() { int[] rgb = getRandomRgb(); int color = 0; for (int c : rgb) { color = color << 8; color = color | c; } return color; } private static int[] getRandomRgb() { int[] rgb = new int[3]; for (int i = 0; i < 3; i++) { rgb[i] = random.nextInt(255); } return rgb; } private static void shear(Graphics g, int w1, int h1, Color color) { shearX(g, w1, h1, color); shearY(g, w1, h1, color); } private static void shearX(Graphics g, int w1, int h1, Color color) { int period = random.nextInt(2); boolean borderGap = true; int frames = 1; int phase = random.nextInt(2); for (int i = 0; i < h1; i++) { double d = (double) (period >> 1) * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames); g.copyArea(0, i, w1, 1, (int) d, 0); if (borderGap) { g.setColor(color); g.drawLine((int) d, i, 0, i); g.drawLine((int) d + w1, i, w1, i); } } } private static void shearY(Graphics g, int w1, int h1, Color color) { int period = random.nextInt(40) + 10; // 50; boolean borderGap = true; int frames = 20; int phase = 7; for (int i = 0; i < w1; i++) { double d = (double) (period >> 1) * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames); g.copyArea(i, 0, 1, h1, 0, (int) d); if (borderGap) { g.setColor(color); g.drawLine(i, (int) d, i, 0); g.drawLine(i, (int) d + h1, i, h1); } } } public static void main(String[] args) throws IOException{ File dir = new File("e:/abc"); int w = 200, h = 80; for(int i = 0; i < 50; i++){ String verifyCode = generateVerifyCode(4); File file = new File(dir, verifyCode + ".jpg"); outputImage(w, h, file, verifyCode); } } } |
上面这段代码就能生成一个验证码,略微修改就能生成各种各样的形式,main方法可以测试.
下面为大家写一下如何返回到页面
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package com.SM_test.saomiao.constroller; import java.io.IOException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import com.SM_test.utils.VerifyCodeUtils; @Controllerpublic class IndexConstroller { @RequestMapping(value = "/index") public void index(HttpServletRequest request,HttpServletResponse response) throws IOException{ response.setHeader("Pragma", "No-cache"); response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expires", 0); response.setContentType("image/jpeg"); //生成随机字串 String verifyCode = VerifyCodeUtils.generateVerifyCode(4); //存入会话session HttpSession session = request.getSession(true); session.setAttribute("rand", verifyCode.toLowerCase()); //生成图片 int w = 200, h = 80; VerifyCodeUtils.outputImage(w, h, response.getOutputStream(), verifyCode); } } |
很简单,用HttpServletResponse 就OK了.
需要显示验证码的地方可以直接用img标签,地址就是该Controller的URL就OK了
以上所述是小编给大家介绍的Java生成验证码功能实例代码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！
原文链接：http://blog.csdn.net/rongbaojian/article/details/72724261
