关于把AJAX加入到注册登录demo中去

2018年3月10日 19:21:23
第一次来SUBWAY真切地打代码. 这次的西红柿汤还是挺好喝的.

index.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>ajax测试</title>
<script src="js/jquery-3.3.1.min.js"></script>
<script>
$(function () {
$("#loginName").bind("blur", function () {
var v_loginName = $(this).val()
$.ajax({
type: "POST", //类型
url: "checkName", //传送地址
data: "loginName=" + v_loginName, //数据
dataType: "json", //数据类型
success: function (data) { //成功回调,当响应一切正常时.
if (!data) {
$("#message").text("对不起,此账号已使用");
$("#message").attr("color","red");
} else {
$("#message").text("恭喜你,本账号可以使用");
$("#message").attr("color","green");
}
},
error: function(){ //当程序出错错误时执行error的回调方法
$("#message").text("对不起,服务器内部错误!请稍候再试!");
$("#message").attr("color","red");
}
})
})
})
</script>
</head>
<body>账号: <input type="text" name="loginName" id="loginName"><span ><font id="message"></font></span></body>
</html>

CheckNameServlet:

package com.ykmimi.login;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(name = "CheckName")
public class CheckNameServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//设置请求编码
request.setCharacterEncoding("UTF-8");
//获取请求数据
String loginName = request.getParameter("loginName");
//简单判定
if ("admin".equals(loginName)) {
request.setAttribute("data",false);
request.getRequestDispatcher("data.jsp").forward(request,response);
return;
}
request.setAttribute("data", true);
request.getRequestDispatcher("data.jsp").forward(request, response);}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
super.doPost(request, response);}
}

根据之上已经实现了Ajax的查询,并已经改为了从数据库直接查询:

package com.ykmimi.login;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;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class CheckNameServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {// 设置请求编码
request.setCharacterEncoding("UTF-8");
// 获取请求数据
String userName = request.getParameter("userName");//
String driverName = "org.mariadb.jdbc.Driver";
String DBUrl = "jdbc:mariadb://**.**.**.**:3306/*****";
String DBUser = "******";
String DBPassword = "************";
PrintWriter pw = response.getWriter();try {
Class.forName(driverName);
Connection conn = DriverManager.getConnection(DBUrl, DBUser, DBPassword);String sql = "SELECT * FROM user WHERE username = '" + userName + "'";
Statement stmt1 = conn.createStatement();
ResultSet name = stmt1.executeQuery(sql);if (name.next()) {
request.setAttribute("data", false);
request.getRequestDispatcher("data.jsp").forward(request, response);
return;
}
request.setAttribute("data", true);
request.getRequestDispatcher("data.jsp").forward(request, response);} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}}protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
super.doPost(request, response);}
}