java生成图片验证码的示例代码

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);
 
  }
}

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  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 > 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 > 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);
    }
  }
}

  AuthImage
  com.sunjs.controller.AuthImage


  AuthImage
  /authImage

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