在jsp页面里怎么样刷新用Servlet产生的验证码？急!!

在jsp页面里怎么样刷新用Servlet产生的验证码？

<input type="text" name="Rand" maxlength="4" size="4" /> <img border="0" src="validatecodeservlet" alt=""/>

请高手赐教

第2楼. 由 ruanjiantaotao 于 2007-5-26 20:54:14 发表

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.*;

import java.util.*;

import com.sun.image.codec.jpeg.*;

import java.awt.*;

import com.sun.image.codec.jpeg.*;

import java.awt.image.BufferedImage;

import java.awt.image.DataBuffer;

import java.awt.geom.GeneralPath;

import javax.swing.*;

import java.math.*;

public class Servlet1

extends HttpServlet {

//Process the HTTP Get request

public void doGet(HttpServletRequest request, HttpServletResponse response) throws

ServletException, IOException {

response.setContentType(request.getContentType());