HttpServletResponse?response)?throws?ServletException,?IOException?{
?
?response.setContentType("image/jpeg");
?response.setHeader("Pragma",?"No-cache");
?response.setHeader("Cache-Control",?"no-cache");
?response.setDateHeader("Expires",?0);
?HttpSession?session?=?request.getSession();
?
?int?width?=?60,?height?=?20;
?
?BufferedImage?image?=?new?BufferedImage(width,?height,
BufferedImage.TYPE_INT_RGB);
?
?//?獲取圖形上下文
?Graphics?g?=?image.getGraphics();
?
?//?生成隨機類
?Random?random?=?new?Random();
?
?//?設定背景色
?g.setColor(getRandColor(200,?250));
?g.fillRect(0,?0,?width,?height);
?
?//?設定字體
?g.setFont(new?Font("Times?New?Roman",?Font.PLAIN,?18));
?
?//?隨機產生155條幹擾線，使圖象中的認證碼不易被其它程序探測到
?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);
?}
?
?//?取隨機產生的認證碼(4位數字)
?String?sRand?=?"";
?for?(int?i?=?0;?i?<?4;?i++)?{
String?rand?=?String.valueOf(random.nextInt(10));
sRand?+=?rand;
//?將認證碼顯示到圖象中
g.setColor(new?Color(20?+?random.nextInt(110),?20?+?random
?.nextInt(110),?20?+?random.nextInt(110)));//?調用函數出來的顏色相同，可能是因為種子太接近，所以只能直接生成
g.drawString(rand,?13?*?i?+?6,?16);
?}
?
?//?將認證碼存入SESSION
?session.setAttribute("rand",?sRand);
?//?圖象生效
?g.dispose();
?ServletOutputStream?responseOutputStream?=?response.getOutputStream();
?//?輸出圖象到頁面
?ImageIO.write(image,?"JPEG",?responseOutputStream);
?
?//?以下關閉輸入流！
?responseOutputStream.flush();
?responseOutputStream.close();
?}
?
static ?Color?getRandColor(int?fc,?int?bc)?{
?//?給定範圍獲得隨機顏色
?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);
?}
?
?/**?
?*?Handles?the?HTTP?GET?method.?
?*
?*?@param?request?
?*servlet?request?
?*?@param?response?
?*servlet?response?
?*/?
?protected?void?doGet(HttpServletRequest?request,
HttpServletResponse?response)?throws?ServletException,?IOException?{
?processRequest(request,?response);
?}
這個是我web裏用的驗證碼，妳可以改改