java - How to get BufferedInputStream from Multipart? -

i'm trying bufferedinputstream uploaded cvs file.

i'm working multipart derived cvs file.

when first multipart, it's bufferedinputstream, buffer null.

but if deeper down, there's buffer in coyoteinputstream , has data.

how can @ second buffer? code below.

and of course it's throwing null exception when gets

while ((multipartdatapos = stream.read(buffer)) >= 0)

what doing wrong? mistaken coyoteinputstream data want?

public byte[] handleuploadedfile(multipart multipart) throws eofexception {

    multipart multipartdata = null;     bufferedinputstream stream = null;      int basicbuffersize = 0x2000;      byte[] buffer = new byte[basicbuffersize];      int bufferpos = 0;      try {          while (multipart.hasnext()) {              int multipartdatapos = bufferpos;              multipartdata = (multipart) multipart.next();              stream = new bufferedinputstream(multipartdata.getinputstream());              while ((multipartdatapos = stream.read(buffer)) >= 0) {                  int len = stream.read(buffer, multipartdatapos, buffer.length - multipartdatapos);                 multipartdatapos += len;             }              bufferpos = bufferpos + multipartdatapos;         }      } ... 

your code doesn't make sense.

while ((multipartdatapos = stream.read(buffer)) >= 0) { 

at point have read multipartdatapos bytes buffer, buffer[0..multipartdatapos-1] contains data read.

    int len = stream.read(buffer, multipartdatapos, buffer.length - multipartdatapos); 

at point doing read, return -1, otherwise add data multipartpos multipartdatapos+len-.

    multipartdatapos += len; 

this step valid if len > 0.

and doing nothing buffer; , next time around loop clobber whatever read.

the correct way read stream in java follows:

while ((count = in.read(buffer)) > 0) {     // use buffer[9..count-1], example out.write(buffer, 0, count); } 

i don't understand why think access underlying stream required or it's going give you don't have.