AJAX实现注册验证用户名

本文实例为大家分享了ajax实现注册验证用户名的具体代码，供大家参考，具体内容如下

功能说明

当用户在注册页面输入用户名并且鼠标焦点离开输入框时，到数据表中去验证该用户名是否已经存在，如果存在提示不可用，否则，提示可用。

接口

public interface userdao {
 public user findname(string name);
}

接口实现类

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页面

<%@ page contenttype="text/html;charset=utf-8" language="java" %>
<html>
 <head>
 <title>ajax实际操作注册验证用户名</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("用户已存在！！！")
      }else {
       $("#show").html("用户名可用")
      }
     }
    })
   })
  });
 </script>
 账号<input type="text" name="username"><span id="show"></span></br>
 密码<input type="password" name="password"></br>
 <input type="submit" value="提交">
 </form>
 </body>
</html>

数据库如下：

运行结果如下：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。