java 如何使用 multipart/form-data 发布 ajax 调用？
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How to post ajax call with multipart/form-data?
提问by JS11
I need to upload a file from extjs page, via AJAX call, to the server. I am able to do it with simple HTML page to servlet but using extjs (v4.0.7) i am not getting file in my servlet when i pars request. Servlet recognizes multipart page but nothing comes with the call. Can anyone tell me what I am doing wrong in my code?
我需要通过 AJAX 调用从 extjs 页面上传文件到服务器。我可以使用简单的 HTML 页面到 servlet 来做到这一点，但是使用 extjs (v4.0.7) 我在解析请求时没有在我的 servlet 中获取文件。Servlet 识别多部分页面，但调用没有任何内容。谁能告诉我我的代码做错了什么？
EXTJS code:
EXTJS代码：
var fileName = Ext.getCmp("fileName").getValue();
Ext.Ajax.request({
url : 'UploadServlet',
method: 'POST',
headers: {'Content-Type': 'multipart/form-data'},
params :{
'fileName': fileName.trim()
},
success: function ( result, request ) {
resultData = result.responseText;
},
failure: function ( result, request ) {
resultData = result.responseText;
}
});
Servlet code:
服务端代码：
protected void doPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException, IOException {
.......
// Check that we have a file upload request
isMultipart = ServletFileUpload.isMultipartContent(request);
response.setContentType("text/html");
java.io.PrintWriter out = response.getWriter( );
if( !isMultipart ){
// display no file attached error
return;
}
// Create a factory for disk-based file items
DiskFileItemFactory factory = new DiskFileItemFactory();
// maximum size that will be stored in memory
factory.setSizeThreshold(maxMemSize);
// Location to save data that is larger than maxMemSize.
factory.setRepository(new File(tempDir));
// Create a new file upload handler
ServletFileUpload upload = new ServletFileUpload(factory);
// maximum file size to be uploaded.
upload.setSizeMax( maxFileSize );
try{
// Parse the request to get file items.
////// fileItems is empty,
////nothing is comming from extjs page/////////
List<FileItem> fileItems = upload.parseRequest(request);
// Process the uploaded file items
Iterator<FileItem> i = fileItems.iterator();
while ( i.hasNext () ) {
FileItem fi = (FileItem)i.next();
if ( !fi.isFormField () ) {
// Get the uploaded file parameters
String fieldName = fi.getFieldName();
String fileName = fi.getName();
String contentType = fi.getContentType();
boolean isInMemory = fi.isInMemory();
long sizeInBytes = fi.getSize();
// check if file exists
File propFile = new File(tempDir, fileName.substring( fileName.lastIndexOf("\")));
if (!propFile.exists()) {
// Write the file
if( fileName.lastIndexOf("\") >= 0 ){
file = new File(tempDir +
fileName.substring( fileName.lastIndexOf("\"))) ;
}else{
file = new File( tempDir +
fileName.substring(fileName.lastIndexOf("\")+1)) ;
}
//InputStream uploadedStream = fi.getInputStream();
fi.write( file ) ;
out.println("Uploaded Filename: " + fileName + " is in " + filePath + "<br>");
}
.....
}
}
回答by rixo
You can't upload a file with AJAX.
您无法使用 AJAX 上传文件。
Ext's Ajaxcan emulate it though. See the doc of the requestmethod. You have to use the formand isUploadoptions.
不过，ExtAjax可以效仿它。请参阅该request方法的文档。您必须使用form和isUpload选项。
However, since you have to use a form anyway, you should look at Ext.form.field.Field(and, as suggested in the doc, to Ext.form.Basic.hasUpload; that will give you a better understanding of the file upload problematic).
但是，由于无论如何您都必须使用表单，因此您应该查看Ext.form.field.Field（并且，正如文档中所建议的， to Ext.form.Basic.hasUpload; 这将使您更好地了解文件上传问题）。
EDIT:In fact, HTML5 and XMLHttpRequest Level 2adds support for file upload. Doesn't change how you have to handle it in Ext, though.
编辑：事实上，HTML5 和 XMLHttpRequest Level 2添加了对文件上传的支持。但是，不会改变您必须在 Ext 中处理它的方式。
