jsp页面怎么调用servlet中生成的验证码
生成验证码的java类:
//用于获取四位随机数 private char mapTable[] = {'0','1','2','3','4','5','6','7','8','9'}; //生成验证码,并返回随机生成的数字 public String getEnsure(int width, int height, OutputStream os){ if (width <= 0) width = 60; if (height <= 0) height = 20; BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB); // 获取图形上下文 Graphics g = image.getGraphics(); // 设定背景色 g.setColor(new Color(0xDCCCCC)); g.fillRect(0, 0, width, height); // 画边框 g.setColor(Color.black); g.drawRect(0, 0, width - 1, height - 1); // 取随机产生的认证码 String strEnsure = ""; // 4代表4位验证码 for (int i = 0; i < 4; ++i){ strEnsure += mapTable[(int) (mapTable.length * Math.random())]; } // 将认证码显示到图象中 g.setColor(Color.red); g.setFont(new Font("Atlantic Inline", Font.PLAIN, 14)); // 画的具体坐标 String str = strEnsure.substring(0, 1); g.drawString(str, 8, 14); str = strEnsure.substring(1, 2); g.drawString(str, 20, 15); str = strEnsure.substring(2, 3); g.drawString(str, 35, 18); str = strEnsure.substring(3, 4); g.drawString(str, 45, 15); // 释放图形上下文 g.dispose(); try{ // 输出图象到页面 ImageIO.write(image, "JPEG", os); } catch (IOException e){ return ""; } return strEnsure; }public class CheckServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //禁用缓存，每次访问此页面，都重新生成 response.setHeader("Pragma","No-cache"); response.setHeader("Cache-Control","no-cache"); response.setDateHeader("Expires", 0); //生成验证码的实例对象 CheckCode ie = new CheckCode(); //调用里面的方法，返回的是生成的验证码中的字符串 String str = ie.getEnsure(0,0,response.getOutputStream()); //获得session，并把字符串保存在session中，为后面的对比做基础 HttpSession session = request.getSession(); session.setAttribute("strEnsure", str); }}
int b=fc+random.nextInt(bc-fc);
return new Color(r,g,b);
}
%>
<%
//设置页面不缓存
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
// 在内存中创建图象
int width=60, height=20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
//生成随机类
Random random = new Random();
// 设定背景色
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height);
//设定字体
g.setFont(new Font("Times New Roman",Font.PLAIN,18));
//画边框
//g.setColor(new Color());
//g.drawRect(0,0,width-1,height-1);
// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
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);
}
// 取随机产生的认证码(4位数字)
String sRand="";
for (int i=0;i<4;i++){
// String rand=String.valueOf(random.nextInt(10));
String rand=String.valueOf(codeTable[(int) (codeTable.length * Math.random())]);
sRand+=rand;
// 将认证码显示到图象中
g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
g.drawString(rand,13*i+6,16);
}
// 将认证码存入session
session.setAttribute("rand",sRand);
// 图象生效
g.dispose();
// 输出图象到页面
try{
ImageIO.write(image, "JPEG", response.getOutputStream());
out.clear();
out = pageContext.pushBody();
}catch(Exception e){
e.getMessage();
}
%>
楼主的这种方法 期待高人指点 呵呵学习了
[解决办法]
这种路径问题可以在浏览器地址栏输入全路径测试
假如servlet是下面这样配置的
<servlet> <display-name>CheckServlet</display-name> <servlet-name>CheckServlet</servlet-name> <servlet-class>com.wangxf.servlet.CheckServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>CheckServlet</servlet-name> <url-pattern>/servlet/CheckServlet</url-pattern> </servlet-mapping>