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ajax连接jsp或servlet,获取MySql为数据

發(fā)布時(shí)間：2023/12/18 编程问答 34 豆豆

生活随笔收集整理的這篇文章主要介紹了 ajax连接jsp或servlet,获取MySql为数据小編覺(jué)得挺不錯(cuò)的,現(xiàn)在分享給大家,幫大家做個(gè)參考.

?當(dāng)然代碼并沒(méi)有嚴(yán)格按規(guī)范寫(xiě)。。。數(shù)據(jù)庫(kù)連接和操作的代碼應(yīng)該單獨(dú)寫(xiě)出來(lái)。。。 html 頁(yè)面中的JS代碼也應(yīng)該單獨(dú)寫(xiě)一個(gè)JS文件，然后引入頁(yè)面即可。其次，jsp中的代碼寫(xiě)到servlet中效果是一樣的。。。

1.html代碼：

Java代碼??

<!DOCTYPE?HTML?PUBLIC?"-//W3C//DTD?HTML?4.01?Transitional//EN">??

<html>??

????<head>??

var?xmlHttp;??

//創(chuàng)建xmlHttpRequest對(duì)象??

function?createXmlHttpObject()???

{??

????if(window.XMLHttpRequest)???

????{???

????????xmlHttp?=?new?XMLHttpRequest();???

????}else?if(window.ActiveXObject)???

????{???

????????xmlHttp?=?new?ActiveXObject("Microsoft.XMLHTTP");???

????}???

????return?xmlHttp;??

}??

function?send()??

{??

????xmlHttp?=?createXmlHttpObject();??

??????

????var?url?=?"refreshAjax.jsp?time="+Math.random();?//加一個(gè)隨機(jī)數(shù)，解決瀏覽器緩存問(wèn)題??????

???????????

????if(xmlHttp)??

????{??

????????xmlHttp.onreadystatechange?=callback;???//注冊(cè)回調(diào)函數(shù)名,只需要函數(shù)名，不要加括號(hào)??

????????//設(shè)置連接信息：??

????????//第一個(gè)參數(shù)：表示http的請(qǐng)求方式，主要使用get和post??

????????//第二個(gè)參數(shù)：表示請(qǐng)求的URL地址，get方式的請(qǐng)求參數(shù)也在URL中??

????????//第三個(gè)參數(shù)：表示采用同步還是異步方式進(jìn)行交互，true表示異步交互??

????????xmlHttp.open("GET",?url,?true);???

??????????

????????//發(fā)送數(shù)據(jù)，開(kāi)始和服務(wù)器端進(jìn)行交互??

????????//同步方式下，send語(yǔ)句會(huì)在服務(wù)器端返回?cái)?shù)據(jù)后才執(zhí)行??

????????//異步方式下，send語(yǔ)句會(huì)立即執(zhí)行??

????????xmlHttp.send(null);???????

????}else{??

????????alert("your?browser?does?not?support?ajax");??

????????return;??

????}??????

}??

//回調(diào)函數(shù)??

function?callback()???

{???

????//判斷對(duì)象的狀態(tài)是交互完成??

????if(xmlHttp.readyState?==?4)???

????{??

????????//判斷http的交互是否成功??

????????if(xmlHttp.status==200)??

????????{??

????????????//獲取服務(wù)器端返回的數(shù)據(jù)??

????????????var?xmlDoc?=?xmlHttp.responseXML;???

??????????????

????????????document.getElementById("name").innerHTML?=?xmlDoc.getElementsByTagName("name")[0].childNodes[0].nodeValue;??????????

????????????document.getElementById("tel").innerHTML?=?xmlDoc.getElementsByTagName("tel")[0].childNodes[0].nodeValue;??

????????????document.getElementById("city").innerHTML?=?xmlDoc.getElementsByTagName("city")[0].childNodes[0].nodeValue;??????????

????????}else{??

????????????alert(xmlHttp.statusText);??

????????}??

????}??

}????????

function?refresh()??

{??

????window.setInterval("send()",1000);?//定時(shí)刷新??

}????

</script>??

????</head>??

????<body?οnlοad="refresh()">??

????????<form?action="">???

????????????選擇用戶(hù)：???

????????????<select?name="employees"?οnchange="send(this.value);">??

????????????????<option?value="Tom">Tom</option>??

????????????????<option?value="Jom">Jom</option>??

????????????????<option?value="Sun">Sun</option>??

????????????</select>??

????????</form>??

????????用戶(hù)名稱(chēng)：??

????????<span?id="name"></span>??

????????<br>??

????????電話：??

????????<span?id="tel"></span>??

????????<br>??

????????城市：??

????????<span?id="city"></span>??

????????<br>??

??????

????</body>??

</html>??

2。Jsp代碼：

???? 連接的是MySql數(shù)據(jù)庫(kù)。。。

Java代碼??

<%@?page?language="java"?import="java.sql.*"?pageEncoding="gb2312"%>??

<%???

????//這句至關(guān)重要，一定注意??

????response.setContentType("text/xml;charset=gb2312");??????

??????

????StringBuffer?str=new?StringBuffer();??

??????

????????try?{??

????????????Class.forName("com.mysql.jdbc.Driver");??

??????????

????????????String?url="jdbc:mysql://localhost:3306/devimonitor?";??

????????????String?userName="root";??

????????????String?password="root";??

????????????Connection?con=DriverManager.getConnection(url,userName,password);??

??????????

????????????Statement?stmt=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);??

??????????????

????????????String?sql="select?*?from?position?order?by?id";??

????????????ResultSet?rs=stmt.executeQuery(sql);??

??????????????

????????????if(rs.last())???

????????????{??

????????????????str.append("<information>");??

????????????????str.append("<name>");str.append(rs.getString(1).trim());str.append("</name>");??

????????????????str.append("<tel>");str.append(rs.getString(2).trim());str.append("</tel>");??

????????????????str.append("<city>");str.append(rs.getString(3).trim());str.append("</city>");??

????????????????str.append("</information>");??

????????????}??

????????????stmt.close();??

????????????con.close();??

????????????rs.close();??

????????}?catch?(Exception?e)???

????????{??

????????????e.printStackTrace();??

????????}??

????

????out.print(str.toString());??

%> ?

轉(zhuǎn)載于:https://www.cnblogs.com/-ksz/p/3322688.html

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编程问答

ajax连接jsp或servlet,获取MySql为数据

總結(jié)