只是简单的仿某度注册的用户名输入离焦后检验
目录结构
没有涉及到数据库
html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>校验用户名是否存在</title>
<script src="js/jquery-3.3.1.min.js"></script>
<script>
//页面加载完成后
$(function () {
//给用户名输入框定义一个离焦事件
$("#username").blur(function () {
//获取文本输入框的值
var username=$(this).val();
/* 期望服务器端响应回来的数据格式是这样的（json）:
{"userExit":true,"msg":"此用户太受欢迎，请换一个"}
{"userExit":false,"msg":"用户名可用"}
*/
$.get("findUsernameServlet",{username:username},function (data) {
alert(data.msg);
var span = $("#s_username")
//判断响应回来的数据的键userExit是否为true
if (data.usernameExsit){
//true 用户名存在
span.css("color","red");
span.html(data.msg);
} else {
//false 用户名不存在
span.css("color","green");
span.html(data.msg);
}
},"json");
});
});
</script>
</head>
<body>
<form action="" method="get">
<input type="text" id="username" name="username" placeholder="请输入用户名">
<span id="s_username"></span><br>
<input type="password" name="password" placeholder="请输入密码"><br>
<input type="submit" value="注册">
</form>
</body>
</html>
java servlet
@WebServlet("/findUsernameServlet")
public class FindUsernameServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String username = request.getParameter("username");
response.setContentType("application/json;charset=utf-8");
Map<String,Object> map=new HashMap<>();
/*判断浏览器客户端传过来的数据 username
true {"userExit":true,"msg":"此用户太受欢迎，请换一个"}
false {"userExit":false,"msg":"用户名可用"}
*/
if ("tom".equals(username)){
map.put("usernameExsit",true);
map.put("msg","此用户太受欢迎，请换一个");
}else {
map.put("usernameExsit",false);
map.put("msg","用户名可用");
}
//java:map-->json
ObjectMapper mapper=new ObjectMapper();
mapper.writeValue(response.getWriter(),map);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
原文地址：https://www.cnblogs.com/shiguanzui/p/11833917.html
时间： 2024-10-16 22:50:19