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服务器之家 - 编程语言 - Java教程 - AJAX+JAVA用户登陆注册验证的实现代码

AJAX+JAVA用户登陆注册验证的实现代码

2021-05-07 11:12haostarlilac Java教程

这篇文章主要介绍了AJAX+JAVA用户登陆注册验证的实现代码,通过ajax异步刷新页面验证用户输入的账号密码是否在数据库中存在。非常具有实用价值,需要的朋友可以参考下

需求

通过ajax异步刷新页面验证用户输入的账号密码是否在数据库中存在。

技术栈

jsp+servlet+oracle

具体代码

jsp部分:

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<%@ page language="java" contenttype="text/html; charset=utf-8"
  pageencoding="utf-8"%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>insert title here</title>
</head>
<script>
  function createxmlhttprequest() {
    try {
      xmlhttp = new xmlhttprequest();//除了ie之外的其他浏览器使用ajax
    } catch (tryms) {
      try {
        xmlhttp = new activexobject("msxml2.xmlhttp");//ie浏览器适配
      } catch (otherms) {
        try {
          xmlhttp = new activexobject("microsoft.xmlhttp");//ie浏览器适配
        } catch (failed) {
          xmlhttp = null;
        }
      }
    }
    return xmlhttp;
  }
  //提交请求
  var xmlhttp;
  function checkuserexists() {
    var u = document.getelementbyid("uname");
    var username = u.value;
    if (username == "") {
      alert("请输入用户名");
      u.focus();
      return false;
    }
    //访问字符串
    var url = "loginservlet";
    //创建核心xmlhttprequest组件
    xmlhttp = createxmlhttprequest();
    //设置回调函数
    xmlhttp.onreadystatechange = proessrequest;
    //初始化核心组件
    xmlhttp.open("post", url, true);
    //设置请求头
    xmlhttp.setrequestheader("content-type","application/x-www-form-urlencoded;");
    //发送请求
    xmlhttp.send("uname="+username);
  }
  //回调函数
  function proessrequest() {
    if (xmlhttp.status==200 && xmlhttp.readystate == 4) {
      var b = xmlhttp.responsetext;//得到服务端的输出结果
      if (b=="true") {
        document.getelementbyid("alert").innerhtml = "<font color='red'>用户名已经存在!</font>";
      }else {
        document.getelementbyid("alert").innerhtml = "<font color='blue'>用户名可以使用!</font>";
      }
    }
  }
</script>
<body>
  请输入用户名:
  <input id="uname" name="uname" type="text" onblur="checkuserexists()" /><div id="alert" style="display:inline"></div>
</body>
</html>

这里没有用dao层,直接用servlet和service层进行验证。

下面是service下jdbc查询的代码:

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import java.sql.connection;
import java.sql.resultset;
import java.sql.sqlexception;
import java.sql.statement;
 
import com.stx.service.user;
import com.stx.service.connectionmanager;
 
public class ajaxservice {
  public boolean searchuser (string uname) {
  //jdbc查询用户名是否存在
    boolean isfalse = false;
    connection connection = null;
    statement stmt = null;
    resultset rs = null;
    connection = connectionmanager.getconnection();
    try {
      stmt = connection.createstatement();
      string sql = "select * from user_b where uname='"+uname+"'";//sql语句
      rs = stmt.executequery(sql);
      isfalse=rs.next();
 
    } catch (sqlexception e) {
      e.printstacktrace();
    } finally {
      connectionmanager.closeresultset(rs);
      connectionmanager.closestatement(stmt);
      connectionmanager.closeconnection(connection);
    }
    return isfalse;
  }
}

jdbc连接代码:

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import java.sql.connection;
import java.sql.drivermanager;
import java.sql.resultset;
import java.sql.sqlexception;
import java.sql.statement;
 
 
public class connectionmanager {
  private final static string driver_class = "oracle.jdbc.oracledriver";
  private final static string url = "jdbc:oracle:thin:@localhost:1521:orcl";
  private final static string dbname = "ibook";
  private final static string password = "qwer";
 
  public static connection getconnection() {
    connection connection = null;
    try {
      class.forname(driver_class);
      connection = drivermanager.getconnection(url, dbname, password);
    } catch (classnotfoundexception e) {
      e.printstacktrace();
    } catch (sqlexception e) {
      e.printstacktrace();
    }
    return connection;
  }
 
  public static void closeresultset(resultset rs) {
    try {
      if (rs != null)
        rs.close();
    } catch (sqlexception e) {
      e.printstacktrace();
    }
  }
 
  public static void closeconnection(connection connection) {
    try {
      if (connection != null && !connection.isclosed())
        connection.close();
    } catch (sqlexception e) {
      e.printstacktrace();
    }
  }
 
  public static void closestatement(statement stmt) {
    try {
      if (stmt != null)
        stmt.close();
    } catch (sqlexception e) {
      e.printstacktrace();
    }
  }
}

关于user类:

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public class user {
   private string uname;
   public user() {
     super();
   }
   public user(string uname) {
     super();
     this.uname = uname;
 
   }
 
   public string getuname() {
     return uname;
   }
   public void setuname(string uname) {
     this.uname = uname;
   }

关于控制层servlet:

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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 com.stx.service.ajaxservice;
 
/**
 * servlet implementation class loginservlet
 */
public class loginservlet extends httpservlet {
  private static final long serialversionuid = 1l;
  private ajaxservice ajaxservice = new ajaxservice();
 
  /**
   * @see httpservlet#httpservlet()
   */
  public loginservlet() {
    super();
    // todo auto-generated constructor stub
  }
 
  /**
   * @see httpservlet#doget(httpservletrequest request, httpservletresponse response)
   */
  protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
    request.setcharacterencoding("utf-8");
    string uname = request.getparameter("uname");//获取到输入的用户名
    boolean isuname = ajaxservice.searchuser(uname);//调用service中的查询方法
    response.setcharacterencoding("utf-8");//设置字符编码
    printwriter out = response.getwriter();
    out.print(isuname);
    out.flush();
    out.close();//关闭资源
  }
 
  /**
   * @see httpservlet#dopost(httpservletrequest request, httpservletresponse response)
   */
  protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
    // todo auto-generated method stub
    doget(request, response);
  }
}

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服务器之家。

原文链接:https://segmentfault.com/a/1190000015150083

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