实现AJAX+JAVA用户登陆注册验证的代码

Java|java教程

AJAX,JAVA,用户登陆注册

Java-java教程

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需求

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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：

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 = "用户名已经存在！";}else { document.getElementById("alert").innerHTML = "用户名可以使用！";} } } 请输入用户名：

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：

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：

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：

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：

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); }}