最近做验证码，参考网上案例，发现有不少问题，特意进行了修改和完善。

验证码生成器：

import javax.imageio.ImageIO;  
import java.awt.*;  
import java.awt.image.BufferedImage;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.io.OutputStream;  
import java.util.Date;  
import java.util.Random;  
/**

• 验证码生成器

• @author
  */
  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 String code = null;
  // 验证码图片Buffer
  private BufferedImage buffImg = null;

  // 验证码范围,去掉0(数字)和O(拼音)容易混淆的(小写的1和L也可以去掉,大写不用了)
  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\’};

  /**

  • 默认构造函数,设置默认参数
    */
    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(左右各空出一个字符)  
   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,可以修改为其它的  
   Font font = new Font("Fixedsys", Font.PLAIN, fontHeight);  
  

// Font font = new Font(“Times New Roman”, Font.ROMAN_BASELINE, fontHeight);
g.setFont(font);

    for (int i = 0; i < lineCount; i++) {  
        // 设置随机开始和结束坐标  
        int xs = random.nextInt(width);//x坐标开始  
        int ys = random.nextInt(height);//y坐标开始  
        int xe = xs + random.nextInt(width / 8);//x坐标结束  
        int ye = ys + random.nextInt(height / 8);//y坐标结束  

        // 产生随机的颜色值，让输出的每个干扰线的颜色值都将不同。  
        red = random.nextInt(255);  
        green = random.nextInt(255);  
        blue = random.nextInt(255);  
        g.setColor(new Color(red, green, blue));  
        g.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 String getCode() {  
    return code;  
}  

/** 
 * 测试函数,默认生成到d盘 
 * @param args 
 */  
public static void main(String[] args) {  
    ValidateCode vCode = new ValidateCode(160,40,5,150);  
    try {  
        String path="D:/"+new Date().getTime()+".png";  
        System.out.println(vCode.getCode()+" >"+path);  
        vCode.write(path);  
    } catch (IOException e) {  
        e.printStackTrace();  
    }  
}  

}

下面是页面JS调用验证码

 // 刷新图片

function changeImg() {

var imgSrc = $("#imgObj");

var url = imgSrc.attr("src");

imgSrc.attr("src", changeUrl(url));

}

//为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳

function changeUrl(url) {

var timestamp = (new Date()).valueOf();

var index = url.indexOf("?");

console.log(index);

if (index > 0) {

url = url.substring(0, url.indexOf("?"));

}

console.log(url);

if ((url.indexOf("&") > 0)) {

url = url + "×tamp=" + timestamp;

console.log(url);

} else {

url = url + "?timestamp=" + timestamp;

console.log(url);

}

return url;

}

下面是controller层输出验证码

/

• 响应验证码页面

• @return
  */
  @RequestMapping(value=”/validateCode”)
  public String validateCode(HttpServletRequest request,HttpServletResponse response) throws Exception{
  // 设置响应的类型格式为图片格式
  response.setContentType(“image/jpeg”);
  //禁止图像缓存。
  response.setHeader(“Pragma”, “no-cache”);
  response.setHeader(“Cache-Control”, “no-cache”);
  response.setDateHeader(“Expires”, 0);

  HttpSession session = request.getSession();

  ValidateCode vCode = new ValidateCode(120,40,5,100);
  session.setAttribute(“code”, vCode.getCode());
  vCode.write(response.getOutputStream());
  return null;
  }

下面是controller层验证验证码输入是否正确

String code = request.getParameter("code");

HttpSession session = request.getSession();

String sessionCode = (String) session.getAttribute("code");

if (!StringUtils.equalsIgnoreCase(code, sessionCode)) {  //忽略验证码大小写

throw new RuntimeException("验证码对应不上code=" + code + "  sessionCode=" + sessionCode);

}