Java数字型验证码生成

生成数字验证码

就是简单的html页面调用jsp页面实现的

jsp代码如下：randomNumber.jsp

<%@ page  import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>  
<%@ page import="java.io.OutputStream" %>  
<%!  
Color getRandColor(int fc,int bc){  
Random random = new Random();  
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);  
}  
%>  
<%  
try{  
response.setHeader("Pragma","No-cache");  
response.setHeader("Cache-Control","no-cache");  
response.setDateHeader("Expires", 0);  
int width=60, height=20;  
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);  
OutputStream os=response.getOutputStream();  
Graphics g = image.getGraphics();  
Random random = new Random();  
g.setColor(getRandColor(200,250));  
g.fillRect(0, 0, width, height);  
  
g.setFont(new Font("Times New Roman",Font.PLAIN,18));  
g.setColor(getRandColor(160,200));  
for (int i=0;i<155;i++)  
{  
int x = random.nextInt(width);  
int y = random.nextInt(height);  
int xl = random.nextInt(12);  
int yl = random.nextInt(12);  
g.drawLine(x,y,x+xl,y+yl);  
}  
String sRand="";  
for (int i=0;i<4;i++){  
String rand=String.valueOf(random.nextInt(10));  
sRand+=rand;  
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));  
g.drawString(rand,13*i+6,16);  
}  
session.setAttribute("rand",sRand);  
g.dispose();  
  
ImageIO.write(image, "JPEG",os);  
  
//注意看以下几句的使用  
os.flush();  
os.close();  
os=null;  
response.flushBuffer();  
out.clear();  
out = pageContext.pushBody();  
}  
catch(IllegalStateException e)  
{  
System.out.println(e.getMessage());  
e.printStackTrace();  
}%> 

html代码调用如下：test.html

    

    

        

            ![](randomNumber.jsp)