图片验证的工具类和配置文件。

src/main/java/com/ekexiu/portal/util/PictureVC.java

@@ -0,0 +1,42 @@
package com.ekexiu.portal.util;
import java.io.IOException;  
import javax.servlet.Servlet;
import javax.servlet.ServletException;  
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
public class PictureVC extends HttpServlet implements Servlet {  
  
	private static final long serialVersionUID = 2459158903781864570L;
	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 verifyCode = VerifyCodeUtils.generateVerifyCode(4);
        //获取上次请求发送的rand的cookie 设置生命为0.
        Cookie[] cookies = request.getCookies();
        for (Cookie cookie : cookies) {
			if("rand".equalsIgnoreCase(cookie.getName())){
				cookie.setMaxAge(0);
			}
		}
        //为随机数创建cookie
        Cookie rand = new Cookie("rand", verifyCode.toLowerCase());
        //设置cookie中随机数的过期时间为1小时
        rand.setMaxAge(60 * 60);
        //在响应头中添加cookie
        response.addCookie(rand);
        //生成图片  
        int w = 100, h = 40;  
        VerifyCodeUtils.outputImage(w, h, response.getOutputStream(), verifyCode);  
  
    }  
} 

src/main/java/com/ekexiu/portal/util/VerifyCodeUtils.java

@@ -0,0 +1,268 @@
package com.ekexiu.portal.util;
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, 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 < 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.drawChars(chars, i, 1, ((w-10) / verifySize) * 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);  
            }  
  
        }  
  
    }
    
//    //测试main函数，输出验证图片到指定路径
//    public static void main(String[] args) throws IOException{  
//        File dir = new File("F:/verifies");  
//        int w = 200, h = 80;  
//        String verifyCode = generateVerifyCode(4);  
//        File file = new File(dir, verifyCode + ".jpg");  
//        outputImage(w, h, file, verifyCode);  
//    }  
}  

src/main/webapp/WEB-INF/web.xml

@@ -36,6 +36,11 @@
  	<servlet-class>com.ekexiu.portal.util.FileDownload</servlet-class>
  	<load-on-startup>4</load-on-startup>
  </servlet>
  <servlet>
  	<servlet-name>PictureVC</servlet-name>
  	<servlet-class>com.ekexiu.portal.util.PictureVC</servlet-class>
  	<load-on-startup>5</load-on-startup>
  </servlet>
  
  <servlet-mapping>
    <servlet-name>ajax</servlet-name>
@@ -53,4 +58,8 @@
    <servlet-name>FileDownload</servlet-name>
    <url-pattern>/ajax/FileDownload</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>PictureVC</servlet-name>
    <url-pattern>/ajax/PictureVC</url-pattern>
  </servlet-mapping>
</web-app>