网页验证码源代码

package random; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import java.util.*; import java.awt.image.*; import java.awt.*; import javax.imageio.ImageIO; public class RandomCodeServlet extends HttpServlet { private static final String CONTENT_TYPE = "text/html; charset=GB2312"; private int width=60; private int height=20; //Initialize global variables public void init() throws ServletException { } //Process the HTTP Get request public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { BufferedImage buffimg= new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); Graphics2D g=buffimg.createGraphics(); //创建随机数 Random random=new Random(); g.setColor(Color.WHITE); g.fillRect(0,0,width,height); Font font=new Font("Times New Roman",Font.PLAIN,18); g.setFont(font); g.setColor(Color.PINK); g.drawRect(0,0,width-1,height-1); g.setColor(Color.LIGHT_GRAY); for(int i=0;i<100;i++){ int x=random.nextInt(width); int y=random.nextInt(height); int x1=random.nextInt(12); int y1=random.nextInt(12); g.drawLine(x,y,x+x1,y+y1); } //randomcoad用于保存随机产生的验证吗，以便用于登陆后进行验证 StringBuffer randomCode=new StringBuffer(); int red=0,green=0,blue=0; //随即产生4为数子验证码 for(int i=0;i<4;i++){ //得到随机产生的验证数字 String strRand=String.valueOf(random.nextInt(10)); //产生随机的颜色分量来构造颜色，这样输出的每位颜色的不同 red=random.nextInt(110); green=random.nextInt(50); blue=random.nextInt(50); randomCode.append(strRand); //用随即产生的颜色将验证码绘制到图象中 g.setColor(new Color(red,green,blue)); g.drawString(strRand,13*i+6,16); //将产生的四个随机数字组合在一起 } //将四位数字保存在session 中 HttpSession session=request.getSession(); session.setAttribute("randomCode",randomCode.toString()); //禁止图象缓冲 response.setHeader("pargma","no-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires",0); response.setContentType("image/jpeg"); ServletOutputStream sos=response.getOutputStream(); ImageIO.write(buffimg,"jpeg",sos); sos.close(); } //Clean up resources public void destroy() { } }