apache HttpClient, upload a file via form: use StringBody instead of FileBody
A web server expects a file to be uploaded via an html form.
This is the way how i construct the MultipartEntity, that already works:
FileBody filePart = new FileBody(new File("emptyFile.txt"), "text/plain");
FormBodyPart fbp = new FormBodyPart("UploadService", filePart);
MultipartEntity mpe = new MultipartEntity();
mpe.addPart(fbp);
The fact is that i have my data in memory, so i don't like the idea of saving it to disk, and so I've tried to replace
FileBody filePart = new FileBody(new File("emptyFile.txt"), "text/plain");
with
StringBody filePart = new StringBody("");
But the second way doesn't work, the server returns a HTTP 500 exception; logging the data on the wire, i noticed that the only difference is as follows:
HTTP POST trace when FileBody has been used:
...
Content-Disposition: form-data; name="UploadService"; filename="emptyFile.txt"
...
HTTP POST trace when StringBody has been used:
...
Content-Disposition: form-data; name="UploadService"
...
That is, in the FileBody upload, it is specified a "filename" that is not specified in the StringBody upload. How can i fix this?
With a StringBody you won't be able to set a filename. But you can extend StringBody and override getFilename() to not return null .
According to the sources for FormBodyPart , this should be enough to have the desired filename-parm parameter:
protected void generateContentDisp(final ContentBody body) {
StringBuilder buffer = new StringBuilder();
buffer.append("form-data; name="");
buffer.append(getName());
buffer.append(""");
if (body.getFilename() != null) {
buffer.append("; filename="");
buffer.append(body.getFilename());
buffer.append(""");
}
addField(MIME.CONTENT_DISPOSITION, buffer.toString());
}
只是放弃这一点，因为我有这个问题，并继续在我的搜索到这里...类似于上面的方法，但我想它更简单。
public class StringFileBody extends FileBody {
private String data;
public StringFileBody( String input, ContentType contentType ) {
super( new File( "." ), contentType );
data = input;
}
public StringFileBody( String input, ContentType contentType, String fileName ) {
super( new File( "." ), contentType, fileName );
data = input;
}
@Override
public void writeTo( OutputStream out ) throws IOException {
out.write( data.getBytes( ) );
}
@Override
public long getContentLength( ) {
return data.getBytes( ).length;
}
}