java JSP AJAX 文件上传
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/5700172/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
JSP AJAX file uploading
提问by Scicare
I tried to upload a file and display content of the file back to the browser with ajax and jsp. However, it doesn't seem to work very well for me.
我尝试使用ajax和jsp上传文件并将文件内容显示回浏览器。但是，它似乎对我来说效果不佳。
Apparently, in JSP page Upload.jsp, when I try to getContentType() from request, request.getcontentType() == null.
显然，在 JSP 页面 Upload.jsp 中，当我尝试从请求中获取 getContentType() 时，request.getcontentType() == null.
Does anyone have experience with this? Thank you much.
有人对此有经验吗？非常感谢。
Form
形式
<form id="uploadform" name="uploadform" enctype="multipart/form-data" action="Upload.jsp" method="post">
<input type="file" name="file" id="listfile" onChange="upload(this.value)"/>
</form>
This is the Javascript function upload(ifile)
这是 Javascript 函数 upload(ifile)
function upload(ifile){
if (window.XMLHttpRequest){
//IE7 + and other browsers
xmlhttp = new XMLHttpRequest();
}else{
//IE 6, 5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
if(xmlhttp == null){
alert("File Uploading is not available because your browser does not support AJAX");
return;
}
//Function to process response form upload.jsp
xmlhttp.onreadystatechange = function(){
if(xmlhttp.readyState == 4 && xmlhttp.status == 200){
var response = xmlhttp.responseText;
alert(response);
}
}
xmlhttp.open("POST", "Upload.jsp?file="+ifile, true);
xmlhttp.send(null);
}
And this is the JSP page Upload.jsp
这是 JSP 页面 Upload.jsp
<%@page import="java.util.StringTokenizer"%>
<%@page import="java.io.*" %>
<%
response.setContentType("text/html");
response.setHeader("Cache-control", "no-cache");
String contentType = request.getContentType();
if ((contentType != null) && (contentType.indexOf("multipart/form-data") >= 0)) {
DataInputStream in = new DataInputStream(request.getInputStream());
//get length of Content type data
int formDataLength = request.getContentLength();
byte dataBytes[] = new byte[formDataLength];
int byteRead = 0;
int totalBytesRead = 0;
//convert the uploaded file into byte code
while (totalBytesRead < formDataLength) {
byteRead = in.read(dataBytes, totalBytesRead,formDataLength);
totalBytesRead += byteRead;
}
//decode byte array using default charset
String file = new String(dataBytes);
//Using StringTokenizer to extract genes list
StringTokenizer st = new StringTokenizer(file, " ");
int numtoken = st.countTokens();
for(int i = 0; i < numtoken-1; i++){
st.nextToken();
}
String a = st.nextToken();
st = new StringTokenizer(a, " \n");
numtoken = st.countTokens();
String postlink = "";
st.nextToken();
st.nextToken();
for(int i = 1; i < numtoken-3; i++){
String temp = st.nextToken();
char[] c = temp.toCharArray();
temp = new String(c, 0, c.length-1);
if(!" ".equalsIgnoreCase(temp)){
postlink = postlink + temp + ",";
}
}
String temp = st.nextToken();
postlink = postlink + temp;
out.println(postlink);
out.flush();
out.close();
}else if (contentType == null){
out.println("Not a valid file");
out.flush();
}
%>
回答by Sangeet Menon
Try the following code...
试试下面的代码...
HTML:
HTML：
<form id="uploadform" name="uploadform" enctype="multipart/form-data" action="Upload.jsp" method="post">
<input type="file" name="file" id="listfile" onChange="upload()"/>
</form>
<iframe id="target-iframe" name="target-iframe">
<div id="status">Uploading....</div>
Javascript:
Javascript：
function upload(){
document.getElementById('uploadform').target = 'target_iframe';
document.getElementById('status').style.display="block";
document.getElementById("uploadform").submit();
}
The above Javascriptcode will redirect the submit to the iframe(Hidden) rather than to the main page itself
上面的Javascript代码会将提交重定向到 iframe(Hidden) 而不是主页本身
JSP:
JSP：
///do the proccessing in the JSP and in the end output your file content on the some message like follows....
out.println("<script type='text/javascript'>");
out.println("parent.document.getElementById('status').innerHTML=\"<center>SUCCESSFULLY UPLOADED</center>\"; alert('SUCCESSFULLY UPLOADED')");
out.println("</script>");
Hope this helps...
希望这可以帮助...
