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

AuthImage

com.sunjs.controller.AuthImage

AuthImage

/authImage

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

30

配置完成，直接启动项目访问，访问路径你们懂！！！

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