[原创]分享我现在用的图形验证码Servlet源码 -- 风信Java论坛 -- Powered by JavaWind.Net

演示：

java代码

package org.javawind.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class SysCode extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
private static final long serialVersionUID = -5981700888850353189L;
public SysCode() {
super();
}
@SuppressWarnings("static-access")
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.setContentType("image/jpeg"); //必须设置ContentType为image/jpeg
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires",0);
//设置图片的长宽验证码长度
int width=60, height=20,len=4;
String base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
int length = base.length();
//创建内存图像
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//获取图形上下文
Graphics g = image.getGraphics();
//创建随机类的实例
Random random = new Random();
//设定图像背景色(因为是做背景，所以偏淡)
g.setColor(getRandColor(random,200,250));
g.fillRect(0, 0, width, height);
//备选字体
String[] fontTypes = {"tahoma","Atlantic Inline","fantasy","Times New Roman","Georgia","Arial", "Helvetica", "sans-serif","System"};
int fontTypesLength = fontTypes.length;
//在图片背景上增加噪点
g.setColor(getRandColor(random,160,200));
g.setFont(new Font("Times New Roman",Font.PLAIN,12));
for (int i=0;i<6;i++)
{
g.drawString("!@#$%^,.;'[javawind.net]/<&*()>:5277",0,5*(i+2));
}
String sRand="",pStr="";
for (int i=0;i<len;i++)
{
int start = random.nextInt(length);
String rand=base.substring(start,start+1);
sRand+=rand;
//设置字体的颜色
g.setColor(getRandColor(random,10,150));
//设置字体
g.setFont(new Font(fontTypes[random.nextInt(fontTypesLength)],Font.BOLD,16));
//将随机验证码画到图片上
//g.drawString(rand,15*i,18);
pStr = sRand.substring(i,i+1);
if(i==0){
g.drawString(pStr,2,14);
}
if(i==1){
g.drawString(pStr,15,16);
}
if(i==2){
g.drawString(pStr,30,15);
}
if(i==3){
g.drawString(pStr,45,13);
}
}
//将认证码存入session
request.getSession().setAttribute("SystemCode",sRand);
g.dispose();
//输出图象到页面
ImageIO.write(image,"JPEG",response.getOutputStream());
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
protected Color getRandColor(Random random,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);
}
}