java生成图片验证码的示例代码
作者：技术客
这篇文章主要介绍了java生成图片验证码的示例代码，帮助大家更好的理解和使用Java，感兴趣的朋友可以了解下
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！！！
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