给大家分享一款java生成验证码的源码，可设置随机字符串，去掉了几个容易混淆的字符，还可以设置验证码位数，比如4位，6位。当然也可以根据前台验证码的位置大小，设置验证码图片的大小。下边是源码分享，直接看吧，很简单！

创建servlet类

import java.io.IOException; import javax.servlet.Servlet;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession; import com.sunjs.utils.CaptchaUtils; public class AuthImage extends HttpServlet implements Servlet { static final long serialVersionUID = 1L; public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, 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 captcha = CaptchaUtils.generateCaptcha(4); //存入会话session HttpSession session = request.getSession(true); session.setAttribute("rand", captcha.toLowerCase()); //生成图片 int w = 200, h = 80; CaptchaUtils.outputImage(w, h, response.getOutputStream(), captcha); }}

创建工具类

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; /** * 验证码 * * @author sun * @date 2016年8月23日 上午10:12:10 */public class CaptchaUtils { // 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,L, o几个容易混淆的字符 public static final String CAPTCHA_CHARS = "23456789ABCDEFGHJKMNPQRSTUVWXYZ"; private static Random random = new Random(); /** * 使用系统默认字符源生成验证码 * * @param captchaSize * 验证码长度 * @return */ public static String generateCaptcha(int captchaSize) { return generateCaptcha(captchaSize, CAPTCHA_CHARS); } /** * 使用指定源生成验证码 * * @param captchaSize * 验证码长度 * @param sources * 验证码字符源 * @return */ public static String generateCaptcha(int captchaSize, String sources) { if (sources == null || sources.length() == 0) { sources = CAPTCHA_CHARS; } int codesLen = sources.length(); Random rand = new Random(DateUtils.getCurrentTimeMillis()); StringBuilder captcha = new StringBuilder(captchaSize); for (int i = 0; i < captchaSize; i++) { captcha.append(sources.charAt(rand.nextInt(codesLen - 1))); } return captcha.toString(); } /** * 生成随机验证码文件,并返回验证码值 * * @param w * @param h * @param outputFile * @param captchaSize * @return * @throws IOException */ public static String outputCaptchaImage(int w, int h, File outputFile, int captchaSize) throws IOException { String captcha = generateCaptcha(captchaSize); outputImage(w, h, outputFile, captcha); return captcha; } /** * 输出随机验证码图片流,并返回验证码值 * * @param w * @param h * @param os * @param captchaSize * @return * @throws IOException */ public static String outputCaptchaImage(int w, int h, OutputStream os, int captchaSize) throws IOException { String captcha = generateCaptcha(captchaSize); outputImage(w, h, os, captcha); return captcha; } /** * 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 captchaSize = 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, 250); 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(160, 200));// 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 < captchaSize; i++) { AffineTransform affine = new AffineTransform(); affine.setToRotation( Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / captchaSize) * i + fontSize / 2, h / 2); g2.setTransform(affine); g2.drawChars(chars, i, 1, ((w - 10) / captchaSize) * i + 5, h / 2 + fontSize / 2 - 10); } 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("D:/verifies"); File dir = new File("/Users/sun/Documents/captcha"); int w = 200, h = 80; for (int i = 0; i < 50; i++) { String captcha = generateCaptcha(4); File file = new File(dir, captcha + ".jpg"); outputImage(w, h, file, captcha); } }}

配置 web.xml

<!-- 图形验证码 --><servlet> <servlet-name>AuthImage</servlet-name> <servlet-class>com.sunjs.controller.AuthImage</servlet-class></servlet><servlet-mapping> <servlet-name>AuthImage</servlet-name> <url-pattern>/authImage</url-pattern></servlet-mapping>

当然也可以增加session的过期时间，不写的话，会有默认的失效时间

<session-config> <session-timeout>30</session-timeout></session-config>

配置完成，直接启动项目访问，访问路径你们懂！！！

以上就是java生成图片验证码的示例代码的详细内容，更多关于java生成图片验证码的资料请关注其它相关文章！