错误
这个是前台
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<%-- <base href="<%=basePath%>"/> --%>
<meta charset="utf-8">
<title>验证码</title>
<script type="text/javascript" src="js/jquery-3.4.1.js"></script>
<script type="text/javascript" src="js/jquery.min.js"></script>
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript">
function reloadCheckImg(){
/* 强制刷新:除了禁止缓存以外,还需要给服务端传递一个唯一的参数值,
参数一般是随机数或者时间,这个参数没有什么实际的意义 */
$("img").attr("src","img.jsp?t="+(new Date().getTime()));//<img src="">
}
$(document).ready(function(){
$("#checkcodeId").blur(function(){
var $checkcode = $("#checkcodeId").val();
//校验:文本框中输入值发送到服务端
//服务端:获取文本框输入的值，和真实验证码图片中的值对比，并返回验证结果
$.post(
"CheckCodeServlet",//发送请求地址
{checkcode:$checkcode},//待发送 Key/value参数
function(result){//发送成功时回调函数
var resulthtml = $("<p>"+result+"</p>");
$("#tip").html(resulthtml);
alert("resulthtml");
});
});
});
</script>
</head>
<body>
验证码:
<input type="text" name="checkcode" id="checkcodeId" size="4">
<!-- 验证码: -->
<a href="javascript:reloadCheckImg();"><img src="img.jsp"></a>
<span id="tip"></span>
</body>
</html>
##这个是后台
package my;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/CheckCodeServlet")
public class CheckCodeServlet extends HttpServlet {
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("111");
String resultTip = "验证码错误";
//获取用户输入的验证码
String checkcodeClient = req.getParameter("checkcode");
//真实的验证码值
String checkcodeServer = (String) req.getSession().getAttribute("CHECKCODE");
if(checkcodeServer.equals(checkcodeClient)) {
resultTip = "g";
}
resp.setContentType("text/html;charset=utf-8");
PrintWriter writer = resp.getWriter();//输出流
writer.write(resultTip);
writer.flush();
writer.close();
}
}
