Java代码生成图片验证码实现详解编程语言

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>