单击按钮时，JSP从数据库填充下拉列表 [英] JSP populate dropdown list from database on button click
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问题描述
这是我的代码
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql" %>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<sql:setDataSource var="db"
driver="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/dbase"
user="root"
password="1asulxayev" />
<sql:query var="select" dataSource="${db}">
select * from dtable
</sql:query>
<select name="lst">
<c:forEach var="result" items="${select.rows}">
<option>${result.name}</option>
</c:forEach>
</select>
<input type="submit" value="Fill" name="btn">
</body>
</html>
这是页面加载下拉列表填充的时间.但是我想当按钮单击时填充下拉列表
This time when page load dropdown list populate. but i want when button click populate dropdown list
推荐答案
以下是使用AJAX的示例代码.有关更多信息，请阅读嵌入式注释.
Here is the sample code using AJAX. For more info read inline comments.
Servlet:
使用doGet()方法从数据库中获取数据，然后简单地将逗号分隔的字符串写入HTTP响应并将其刷新到客户端.
Fetch the data from the database in doGet() method and simply write a comma separated string the HTTP response and flush it to the client.
HTML:
<head>
<script type="text/javascript">
$(document).ready(
function() { // When the HTML DOM is ready loading, then execute the following function...
$('.btn-click').click(
function() { // Locate HTML DOM element with ID "somebutton" and assign the following function to its "click" event...
$.get('myServletURL', function(responseJson) { // Execute Ajax GET request on URL of "someservlet" and execute the following function with Ajax response JSON...
//alert(responseJson);
var $select = $('#maindiv'); // Locate HTML DOM element with ID "someselect".
$select.find('option').remove(); // Find all child elements with tag name "option" and remove them (just to prevent duplicate options when button is pressed again).
var items = responseJson.split(',');
for ( var i = 0; i < items.length; i++) {
$('<option>').val(items[i]).text(items[i])
.appendTo($select); // Create HTML <option> element, set its value with currently iterated key and its text content with currently iterated item and finally append it to the <select>.
}
});
});
});
</script>
</head>
<body>
<select id="maindiv" style="width: 300px;"></select>
<input type="button" class="btn-click" id="best" value="check" />
</body>
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