Ajax检测用户名是否已经注册
程序员文章站
2022-07-13 16:54:45
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程序功能
当用户名输入完成（即用户名输入框失去焦点），把数据传递给MySQL数据库，利用Ajax检测用户名是否已经注册！
服务器：tomcat 数据库：MySQL
HTML部分
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- uName uPwd传到后台 -->
username:<input type="text" id="uName"/><br/>
pwd:<input type="password" id="uPwd" /><br/>
<button id="loginBtn">点击登录</button><span id="loginMsg"></span>
<script type="text/javascript" src="js/jquery/jquery-1.7.2.min.js"></script>
<script type="text/javascript">
$("#loginBtn").click(function(){
var uName=$("#uName").html()
var uPwd=$("#uPwd").html()
$.ajax({
type: "POST",
url: "login",
data: "uName="+uName+"&uPwd="+uPwd,
success: function(data){
var str =$.parseJSON(data);
if(data=='3'){
$("#loginMsg").text("账户/密码错误 请重试")
alert("3");
}else if(data=='0'){
$("#loginMsg").text("账户被禁用，请联系管理员")
}
else if(data=='1'){
window.location.href='main.html'
}
}
});
})
</script>
</body>
</html>
XML配置部分
<!-- login配置文件 -->
<servlet>
<servlet-name>loginServlet</servlet-name>
<servlet-class>com.gezhi.controller.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>loginServlet</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
Dao部分
package com.gezhi.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.List;
import com.gezhi.pojo.User;
import com.gezhi.pojo.UserInfo;
import com.gezhi.util.JDBCUtil;
public class LoginDao {
public User getUser(String uName ,String uPwd) throws Exception{
Connection conn = JDBCUtil.getCon();
StringBuilder sb = new StringBuilder();
sb.append("select user_name, user_pwd, user_id ,user_type from users ");
sb.append(" WHERE user_name=? AND user_pwd=? ");
PreparedStatement ptmt = conn.prepareStatement(sb.toString());
ptmt.setString(1, uName);
ptmt.setString(2, uPwd);
User users = new User();
ResultSet rs= ptmt.executeQuery();
if(rs.next()){
int userId=rs.getInt("user_id");
String userName=rs.getString("user_name");
String userPwd = rs.getString("user_pwd");
int userType=rs.getInt("user_type");
users.setUserName(userName);
users.setUserPwd(userPwd);
users.setUserType(userType);
System.out.println("找到了");
}
else {
System.out.println("没找到");
}
JDBCUtil.closeAll(rs, ptmt, conn);
return users;
}
}
servlet部分
package com.gezhi.controller;
/**
* @功能 登录程序
*/
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.gezhi.dao.LoginDao;
import com.gezhi.pojo.User;
public class LoginServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
PrintWriter out = resp.getWriter();
String name =req.getParameter("uName");
String pwd = req.getParameter("uPwd");
String type = req.getParameter("type");
//调用Dao层的 loginDao 类中的 方法 拿到它的返回值
LoginDao dao = new LoginDao();
try {
// System.out.println(1); // flag
User user = dao.getUser(name, pwd);
// System.out.println(2); // flag
//对返回值进行判断 如果不是空 就说明找到了 就像前端发送 1
if (user!=null&&user.getUserType()!=null) {
if(user.getUserType()==0){
//禁止登录
out.print("0");
}else if(user.getUserType()==1){
//登录成功
out.print("1");
//保存用户状态
HttpSession session=req.getSession();
//session.setMaxInactiveInterval(2*60*60);
session.setAttribute("user", user);
System.out.println(session.getMaxInactiveInterval());
}
}
//否则就是账号或者密码有问题
else if(user==null){
//帐户名/密码错误
out.print("3");
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
out.print("3");
}
}
}
JDBC工具类
package com.gezhi.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* 工具层
* @author Administrator
*
*/
public class JDBCUtil {
public static final String URL = "jdbc:mysql://localhost:3306/tb40";
public static final String USER = "root";
public static final String PASSWORD = "123456";
static {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 创建数据库连接
*/
public static Connection getCon() {
Connection conn = null;
try {
conn = DriverManager.getConnection(URL,USER,PASSWORD);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
/**
* 关闭结果集，关闭预处理平台，关闭数据库连接
* @param rs
* @param prepare
* @param conn
*/
public static void closeAll(ResultSet rs,PreparedStatement prepare,Connection conn){
if(rs != null) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(prepare != null) {
try {
prepare.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(conn != null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
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