login.jsp代码
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>oa自动化办公系统</title>
<link rel="stylesheet" href="/soa/css/login.css" />
<script type="text/javascript" src="/soa/js/jquery-3.0.0.js" ></script>
<script type="text/javascript">
$(function() {
$("#verifyimg").click(function() {
$.get("/soa/identCodeServlet.do", function(data) {
//此处是刷新的关键
$("#verifyimg").attr("src", "/soa/identCodeServlet.do");
});
});
});
</script>
</head>
<body>
<div id="login">
<div>
<form action="" method="post">
<table>
<tr><td colspan="3"><h2>oa自动办公系统</h2><span id="s_1">登陆</span></td></tr>
<tr><td class="f1">用户名：</td><td colspan="2"><input class="in1" type="text" name="lname" /></td></tr>
<tr><td class="f1">密 码：</td><td colspan="2"><input class="in1" type="password" name="lpwd" /></td></tr>
<tr><td class="f1">验证码：</td><td><input class="in1" id="v1" maxlength="4" type="text" name="verify " /></td><td><img id="verifyimg" src="/soa/identCodeServlet.do"></td></tr>
<tr><td colspan="3"><input id="submit" type="submit" value="登陆" /></td></tr>
</table>
</form>
</div>
</div>
</body>
</html>IdentCodeServlet.java 代码
package com.eduask.oa.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.p_w_picpath.BufferedImage;
import java.io.IOException;
import javax.p_w_picpathio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.eduask.oa.util.CreateRandomCode;
/**
* 将生成的验证码作为图片输出
* @author Maibenben
*
*/
public class IdentCodeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 禁止浏览器缓存随机图片
response.setDateHeader("Expires", -1);
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
//2.通知服务器以图片的方式发送数据
response.setHeader("Content-Type", "p_w_picpath/jpeg");
//3.在内存创建一张图片
BufferedImage p_w_picpath = new BufferedImage(150, 50, BufferedImage.TYPE_INT_BGR);
//4.向图片上写数据
Graphics g = p_w_picpath.getGraphics();
//5.设置背景色
g.setColor(Color.gray);
g.fillRect(0, 0, 150, 50);
//6. 设置写入数据的颜色和字体
g.setColor(Color.red);
g.setFont(new Font(null, Font.BOLD, 50));
// 7.想图片上写数据
String randomNum = new CreateRandomCode().createRandomCode();
request.getSession().setAttribute("checkRandomCode", randomNum);
g.drawString(randomNum, 20, 40);
System.out.println(randomNum);
// 8.把写好的图片输出到浏览器
ImageIO.write(p_w_picpath, "jpg", response.getOutputStream());
}
}生成4位随机验证码代码 CreateRandomCode.java
package com.eduask.oa.util;
/**
* 随机产生4位 数字或字母混合
* @author Maibenben
*
*/
public class CreateRandomCode {
private char[] code = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i',
'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
/**
* 生成4位验证码
* @return
*/
public String createRandomCode() {
char[] codeRandom = new char[4];
//循环取得其中随机字符
for(int i=0; i< codeRandom.length; i++) {
int random = (int)(Math.random()*code.length);
codeRandom[i] = code[random];
}
//将字符数组转为String
StringBuffer sb = new StringBuffer();
for(int i=0; i<codeRandom.length; i++) {
sb.append(codeRandom[i]);
}
return sb.toString();
}
}这只是简单的验证码图片刷新，希望可以帮到正在寻找答案的你