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If you're happy with the defaults, there is no need to put any of the properties in struts.properties.
| Code Block |
|---|
| language | text |
|---|
| title | struts.properties |
|---|
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# put the uploaded files in /tmp. My application will move them to their
# final destination
struts.multipart.saveDir=/tmp
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Note, while you can set these properties to new values at runtime the MultiPartRequestWrapper is created and the file handled before your Action code is called. So if you want to change values you must do so before this Action.
Sample Form
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<%@ taglib uri="action2" prefix="s" %>
<html>
<head>
<title>File Upload Test</title>
</head>
<body>
<h1>File Upload</h1>
<form action="FileUpload.action" method="POST" enctype="multipart/form-data">
<center>
<table width="350" border="0" cellpadding="3" cellspacing="0">
<tr>
<td colspan="2"><input type="file" name="FileName" value="Browse..." size="50"/></td>
</tr>
<tr>
<td colspan="2" align="center">
<input type="submit" value="Submit">
</td>
</tr>
</table>
</center>
</form>
</body>
</html>
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Before the Action method is called the dispatcher will upload the file. Then we can get access to information about the file from MultiPartRequestWrapper.
| Code Block |
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| language | java |
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| title | FileUploadAction.java |
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MultiPartRequestWrapper multiWrapper =
(MultiPartRequestWrapper) ServletActionContext.getRequest();
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The first thing you should always do is check for errors. If there were any, there's no point in continuing, most methods will return null. Unfortunately, currently there is no easy way to distinguish what error occured making it more difficult to route to different error pages.
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if (multiWrapper.hasErrors()) {
Collection errors = multiWrapper.getErrors();
Iterator i = errors.iterator();
while (i.hasNext()) {
addActionError((String) i.next());
}
return ERROR;
}
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Now get the input tag name for the uploaded file and use that to get information on the transfer. Since you can upload multiple files (just add multiple input tags) at a time getFileNames returns an Enumeration of the names.
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Enumeration e = multiWrapper.getFileNames();
while (e.hasMoreElements()) {
// get the value of this input tag
String inputValue = (String) e.nextElement();
// get the content type
String contentType = multiWrapper.getContentType(inputValue);
// get the name of the file from the input tag
String fileName = multiWrapper.getFilesystemName(inputValue);
// Get a File object for the uploaded File
File file = multiWrapper.getFile(inputValue);
// If it's null the upload failed
if (file == null) {
addActionError("Error uploading: " + multiWrapper.getFilesystemName(inputValue));
}
// Do additional processing/logging...
}
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...
