介绍一个使用Java代码生成随机图片验证码的示例

可以直接配置成Servlet，在页面直接调用

Java代码随机生成图片验证码

import java.awt.Color;            import java.awt.Font;    import java.awt.Graphics2D;    import java.awt.image.BufferedImage;    import java.io.FileOutputStream;    import java.io.IOException;    import java.io.OutputStream;    import java.util.Random;            import javax.imageio.ImageIO;            /**    * 验证码生成器    */    public class ValidateCode {        // 图片的宽度。    private int width = 160;    // 图片的高度。    private int height = 40;    // 验证码字符个数    private int codeCount = 5;    // 验证码干扰线数    private int lineCount = 150;    // 验证码    private static String code = null;    // 验证码图片Buffer    private BufferedImage buffImg=null;            private char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J','K', 'L',     'M', 'N',  'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W','X', 'Y',     'Z',  '1', '2', '3', '4', '5', '6', '7', '8', '9' };            public  ValidateCode() {    this.createCode();    }            /**   *    * @param width 图片宽   * @param height 图片高   */    public  ValidateCode(int width,int height) {    this.width=width;    this.height=height;    this.createCode();    }        /**   *    * @param width 图片宽   * @param height 图片高   * @param codeCount 字符个数   * @param lineCount 干扰线条数   */    public  ValidateCode(int width,int height,int codeCount,int lineCount) {    this.width=width;    this.height=height;    this.codeCount=codeCount;    this.lineCount=lineCount;    this.createCode();    }        public void createCode() {    int x = 0,fontHeight=0,codeY=0;    int red = 0, green = 0, blue = 0;        x = width / (codeCount +2);//每个字符的宽度    fontHeight = height - 2;//字体的高度    codeY = height - 4;        // 图像buffer    buffImg = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);    Graphics2D g = buffImg.createGraphics();    // 生成随机数    Random random = new Random();    // 将图像填充为白色    g.setColor(Color.WHITE);    g.fillRect(0, 0, width, height);    // 创建字体    ImgFontByte imgFont=new ImgFontByte();    Font font =imgFont.getFont(fontHeight);    g.setFont(font);        for (int i = 0; i < lineCount; i++) {    int xs = random.nextInt(width);    int ys = random.nextInt(height);    int xe = xs+random.nextInt(width/8);    int ye = ys+random.nextInt(height/8);    red = random.nextInt(255);    green = random.nextInt(255);    blue = random.nextInt(255);    g.setColor(new Color(red, green, blue));    g.drawLine(xs, ys, xe, ye);    }        // randomCode记录随机产生的验证码    StringBuffer randomCode = new StringBuffer();    // 随机产生codeCount个字符的验证码。    for (int i = 0; i < codeCount; i++) {    String strRand = String.valueOf(codeSequence[random.nextInt(codeSequence.length)]);    // 产生随机的颜色值，让输出的每个字符的颜色值都将不同。    red = random.nextInt(255);    green = random.nextInt(255);    blue = random.nextInt(255);    g.setColor(new Color(red, green, blue));    g.drawString(strRand, (i + 1) * x, codeY);    // 将产生的四个随机数组合在一起。    randomCode.append(strRand);    }    // 将四位数字的验证码保存到Session中。    code = randomCode.toString();    }        public void write(String path) throws IOException {    OutputStream sos = new FileOutputStream(path);    this.write(sos);    }        public void write(OutputStream sos) throws IOException {    ImageIO.write(buffImg, "png", sos);    sos.close();    }        public BufferedImage getBuffImg() {    return buffImg;    }        public static String getCode() {    return code;    }        }  

在 servlet 中使用该类：

    import java.io.IOException;            import javax.servlet.ServletException;    import javax.servlet.http.HttpServlet;    import javax.servlet.http.HttpServletRequest;    import javax.servlet.http.HttpServletResponse;    import javax.servlet.http.HttpSession;            public class ValidateCodeServlet extends HttpServlet {        private static final long serialVersionUID = 1L;            protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {    response.setContentType("image/jpeg");    response.setHeader("Pragma", "no-cache");    response.setHeader("Cache-Control", "no-cache");    response.setDateHeader("Expires", 0);    ValidateCode vCode = new ValidateCode(100,30,4,100);    HttpSession session = request.getSession();    session.removeAttribute("validateCode");    vCode.write(response.getOutputStream());    session.setAttribute("validateCode", vCode.getCode());    vCode.write(response.getOutputStream());    }        }  

在 web.xml配置Servlet访问路径：

    <servlet>        <servlet-name>validateCodeServlet</servlet-name>        <servlet-class>com.rchm.util.images.ValidateCodeServlet</servlet-class>        </servlet>         <servlet-mapping>        <servlet-name>validateCodeServlet</servlet-name>        <url-pattern>code.images</url-pattern>