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jquery的ajax登录/注册验证用户名是否被占用

2017-07-20 00:00 531 查看

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>用户注册</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<style type="text/css">
.error{
color: red;
}
</style>
<script type="text/javascript"
src="${pageContext.request.contextPath }/js/jquery-2.1.4.js"></script>
</head>
<body>
<form method="post" action="">
<table>
<tr>
<td>用户名</td>
<td><input type="text" name="username" id="username"></td>
<td><span id="username_msg"></span></td>
</tr>
<tr>
<td>密码</td>
<td><input type="password" name="username"></td>
<td><span id="pwd_msg"></span></td>
</tr>
<tr>
<td colspan="3"><input type="submit" id="sub"></td>
</tr>
</table>
</form>
</body>
<script type="text/javascript">
//加载
$(function(){
//派发失去焦点事件
$("#username").blur(function(){
//获取输入的值
var $username = $(this).val();
//alert($username);
if ($username.trim() == "") {
$("#username_msg").addClass("error");
$("#username_msg").html("不能为空");
}else {
var url="${pageContext.request.contextPath}/registerServlet";
var param={"username":$username}
$.post(url,param,function(data){
if ( data == 0) {
$("#username_msg").removeClass("error");
$("#username_msg").html("可以使用");
}else {
$("#username_msg").addClass("error");
$("#username_msg").html("已被占用");
}
},"json")
}
});
});
</script>
</html>

public class RegisterServlet extends HttpServlet {
private static final long serialVersionUID = 1829647009178241100L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws UnsupportedEncodingException {
//设置编码
//获取用户名
request.setCharacterEncoding("utf-8");
String username = request.getParameter("username");
System.out.println(username);
User user = null;
try {
//调用业务层
user = new UserService().checkUsername4Ajax(username);
System.out.println(user);
if (user != null) {
response.getWriter().println("1");
} else {
response.getWriter().println("0");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

public class UserService {

//调用持久层，查询用户名是否被占用
public static User checkUsername4Ajax(String username) throws SQLException {
return  new UserDao().checkUsername4Ajax(username);
}
}

public class UserDao {

public static User checkUsername4Ajax(String username) throws SQLException {
//System.out.println(username);
QueryRunner qr = new QueryRunner(DataSourceUtils.getDataSource());
String sql = "select * from t_user where username= ? limit 1";
return qr.query(sql, new BeanHandler<User>(User.class),username);
}
}

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