AJAX自学练习 无刷新从数据库后台取数据显示
编程学习 2021-07-05 11:23www.dzhlxh.cn编程入门
AJAX自学练习 无刷新从数据库后台获取数据并显示的代码，大家可以参考下。
请求页面request.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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>
<script language="javascript"><!--
function GetXmlHttpObject(){
var xmlHttp = null;
try{
xmlHttp = new XMLHttpRequest();
}catch(e){
try{
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
}
return xmlHttp;
}
function showMsg(str){
xmlHttp = GetXmlHttpObject();
if(xmlHttp == null){
alert ("you browser don't support the ajax");
return;
}
var url = "response.jsp";
url = url + "?q="+ str;
url = url + "&sid ="+ Math.random();
xmlHttp.onreadystatechange = stateChanged;
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
function stateChanged()
{
if(xmlHttp.readyState==4)
{
document.getElementById("showHint").innerHTML = xmlHttp.responseText;
}
}
// --></script>
</head>
<body>
<form name="form1" action="" method="post">
<p>RocarsId:</p>
<select name="select1" onchange="showMsg(document.form1.select1.options[document.form1.select1.selectedIndex].value)" >
<option value="140">140</option>
<option value="150">150</option>
</select>
<div id="showHint">Show rocars ccrn messages.</div>
</form>
</body>
</html>
response.jsp
<%@ page language="java" contentType="text/plain; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="com.lwf.eus.util.*,java.util.*,com.lwf.eus.entity.*,com.lwf.eus.bean.*" %>
<html>
<head>
<title>response the ccrn</title>
</head>
<body>
<%
String q = request.getParameter("q");
System.out.println("message:" + q);
RocarsBean rocars = RocarsEntity.getRocarsListById(q);
%>
<table>
<tr>
<td>RocarsId</td>
<td>RocarsCcrn</td></tr>
<tr>
<td><%=rocars.getRocarsId() %></td>
<td><%=rocars.getCcrn() %></td>
</tr>
</table>
</body>
</html>
注意这里与自学练习一不同的是，request.jsp页面用一个div来显示信息，response.jsp从数据库里面查询出来的内容放在table标签里，其它的html标签不会在div里面显示。
代码如下:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!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>
<script language="javascript"><!--
function GetXmlHttpObject(){
var xmlHttp = null;
try{
xmlHttp = new XMLHttpRequest();
}catch(e){
try{
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
}
return xmlHttp;
}
function showMsg(str){
xmlHttp = GetXmlHttpObject();
if(xmlHttp == null){
alert ("you browser don't support the ajax");
return;
}
var url = "response.jsp";
url = url + "?q="+ str;
url = url + "&sid ="+ Math.random();
xmlHttp.onreadystatechange = stateChanged;
xmlHttp.open("GET", url, true);
xmlHttp.send(null);
}
function stateChanged()
{
if(xmlHttp.readyState==4)
{
document.getElementById("showHint").innerHTML = xmlHttp.responseText;
}
}
// --></script>
</head>
<body>
<form name="form1" action="" method="post">
<p>RocarsId:</p>
<select name="select1" onchange="showMsg(document.form1.select1.options[document.form1.select1.selectedIndex].value)" >
<option value="140">140</option>
<option value="150">150</option>
</select>
<div id="showHint">Show rocars ccrn messages.</div>
</form>
</body>
</html>
response.jsp
代码如下:
<%@ page language="java" contentType="text/plain; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="com.lwf.eus.util.*,java.util.*,com.lwf.eus.entity.*,com.lwf.eus.bean.*" %>
<html>
<head>
<title>response the ccrn</title>
</head>
<body>
<%
String q = request.getParameter("q");
System.out.println("message:" + q);
RocarsBean rocars = RocarsEntity.getRocarsListById(q);
%>
<table>
<tr>
<td>RocarsId</td>
<td>RocarsCcrn</td></tr>
<tr>
<td><%=rocars.getRocarsId() %></td>
<td><%=rocars.getCcrn() %></td>
</tr>
</table>
</body>
</html>
注意这里与自学练习一不同的是，request.jsp页面用一个div来显示信息，response.jsp从数据库里面查询出来的内容放在table标签里，其它的html标签不会在div里面显示。
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