AJAX實現(xiàn)注冊驗證用戶名

更新時間：2021年03月07日 10:18:59 作者：朱懷昌

這篇文章主要為大家詳細(xì)介紹了AJAX實現(xiàn)注冊驗證用戶名，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文實例為大家分享了AJAX實現(xiàn)注冊驗證用戶名的具體代碼，供大家參考，具體內(nèi)容如下

功能說明

當(dāng)用戶在注冊頁面輸入用戶名并且鼠標(biāo)焦點離開輸入框時，到數(shù)據(jù)表中去驗證該用戶名是否已經(jīng)存在，如果存在提示不可用，否則，提示可用。

接口

public interface UserDao {
 public User findName(String name);
}

接口實現(xiàn)類

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class UserDaoImpl implements UserDao {

 @Override
 public User findName(String name) {
  User user =null;
  Connection conn = DBHelper.getConn();
  String sql = "select * from user where name=?";
  try {
   PreparedStatement ps = conn.prepareStatement(sql);
   ps.setString(1,name);
   ResultSet rs = ps.executeQuery();
   if (rs.next()){
    user = new User();
    user.setId(rs.getInt(1));
    user.setName(rs.getString(2));
    user.setPassword(rs.getString(3));
   }
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return user;
 }
}

servlet

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/findName")
public class FindNameServlet extends HttpServlet {
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  request.setCharacterEncoding("utf-8");
  response.setContentType("text/html;charset=utf-8");
  String name = request.getParameter("name");
  UserDao userDao = new UserDaoImpl();
  User name1 = userDao.findName(name);
  if (name1!=null){
   response.getWriter().write("1");
  }else {
   response.getWriter().write("2");
  }
 }

 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  this.doPost(request, response);
 }
}

JSP頁面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
 <head>
 <title>AJAX實際操作注冊驗證用戶名</title>
 <script src="js/jquery-1.8.3.js"></script>
 </head>
 <body>
 <form action="#" method="post">
 <script type="text/javascript">
  $(function () {
   $("[name=userName]").blur(function () {
    $.ajax({
     type:"get",
     url:"findName?name="+$("[name=userName]").val(),
     dataType:"text",
     success:function (data) {
      //alert(data);
      if (data=="1"){
       $("#show").html("用戶已存在！！！")
      }else {
       $("#show").html("用戶名可用")
      }
     }
    })
   })
  });
 </script>
 賬號<input type="text" name="userName"><span id="show"></span></br>
 密碼<input type="password" name="password"></br>
 <input type="submit" value="提交">
 </form>
 </body>
</html>

數(shù)據(jù)庫如下：