[英]JSP + Ajax not working
目標:如果我鍵入電子郵件ID,則必須以html格式將請求發送到jsp,在該處執行邏輯,並且必須打印(以html格式)是否有電子郵件可用。 我有以下代碼。 請幫我做錯哪一部分。
CreateAccount.html
<!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=ISO-8859-1">
<script type="text/javascript" src="emailStore.js"></script>
</head>
<body onload="process()">
<form name="login">
<table align="center">
<tr>
<td>Email*</td>
<td><input type="text" name="userinput" id="userinput"/></td>
<td><div id = "underInput"></div></td>
</tr>
<tr>
<td>Password*</td>
<td><input type="password" name="pswrd" /></td>
</tr>
<tr>
<td>Repeat Password*</td>
<td><input type="password" name="pswrd1" /></td>
</tr>
<tr>
<td>First Name*</td>
<td><input type="text" name="userid" /></td>
</tr>
<tr>
<td>Last Name*</td>
<td><input type="text" name="userid" /></td>
</tr>
<tr>
<td>Phone Number</td>
<td><input type="text" name="userid" /></td>
</tr>
</table>
<div style="text-align: center">
<input type="submit" value="Create Account"/>
</div>
</form>
</body>
</html>
javascript文件中的ajax部分。 emailStore.js
var xmlHttp = createXmlHttpRequestObject();
function createXmlHttpRequest()
{
var xmlHttp;
if(window.ActiveXObject)
{
try
{
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
catch(e)
{
xmlHttp = false;
}
}
else
{
try
{
xmlHttp = new ActiveXObject();
}
catch(e)
{
xmlHttp = false;
}
}
if(!xmlHttp)
{
alert("can't create that object");
}
else
{
return xmlHttp;
}
}
function process()
{
if(xmlHttp.readyState==0 || xmlHttp.readyState==4)
{
email = encodeURIComponent(document.getElementById("userinput").value);
xmlHttp.open("GET", "emailStore.jsp?email=" + email, true);
xml.onreadystatechange = handle.ServerResponse;
xmlHttp.send(null);
}
else
{
setTimeout('process()', 1000);
}
}
function handleServerResponse()
{
if(xmlHttp.readyState==4)
{
if(xmlHttp.status==200)
{
xmlResponse = xmlHttp.responseXML;
xmlDocumentElement = xmlResponse.documentElement;
message = xmlDocumentElement.firstChild.data;
document.getElementById("underInput").innerHTML = '<span style = "color:blue">' + message + '</span>';
setTimeout('process()',1000);
}
else
{
alert('Something went Wrong');
}
}
}
以及jsp文件中的邏輯部分-emailStore.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.util.ArrayList"%>
<!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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
String email = request.getParameter("userinput");
ArrayList<String> emails = new ArrayList<String>();
emails.add("something@gmail.com");
if (emails.contains(email)) {
out.println("Email already taken!");
} else {
out.println("Email available");
}
%>
</body>
</html>
我建議您注意以下幾點:
- 使用庫JQuery ;
- 使用Servlet代替JSP;
- 在會話中保留一個列表;
- 不要使用表格布局 。 相反,請使用div和層疊樣式表。
這是一個簡單的示例,前端部分是..
<head>
...
<script>
$(document).ready(function() {
$('#submit').click(function(event) {
var input=$('#userinput').val();
$.get('ActionServlet',{userinput:input},function(responseText) {
$('#underInput').text(responseText);
});
});
});
</script>
...
</head>
<body>
...
<form id="form1">
...
Email
<input type="text" id="userinput"/>
<input type="button" id="submit" value="Submit"/>
<br/>
<div id="underInput">
</div>
...
</form>
...
</body>
</html>
..和服務器端-
...
public class ActionServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public ActionServlet() {
// TODO Auto-generated constructor stub
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String answer = "Something went Wrong";
String userinput = request.getParameter("userinput").toString();
HttpSession httpSession = request.getSession(true);
if(httpSession.isNew()) {
httpSession.setAttribute("sessionVar", new ArrayList<String>());
}
List<String> arrayList = (ArrayList<String>)httpSession.getAttribute("sessionVar");
if(userinput != null && !userinput.equals("")) {
if(arrayList.contains(userinput)) {
answer = "Email already taken!";
} else {
arrayList.add(userinput);
answer = "Email available";
}
}
response.setContentType("text/plain");
response.setCharacterEncoding("UTF-8");
response.getWriter().write(answer);
}
...
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