如何将inputstream记录到android中的文件然后解析

Question

I am receiving an InputStream from HttpUrlConnection (connection.getInputStream()), and I am parsing the input stream using DocumentBuilder (documenbtBuilder.parse(inputStream)). Before parsing, I want to write the received data to log file. When I do that, I get org.xml.sax.SAXParseException: Unexpected end of document Exception in the parse method. My code works fine if I don't write to file, but I need to log the data received.

Please find the code that writes to file below :

  final InputStream input = connection.getInputStream();

    writeLogInfo(input);

    Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(input);

    //Method that writes tito log file.

    private void writeLogInfo(InputStream input){

     OutputStream os = new FileOutputStream("mylogfile.txt");

     byte[] buffer = new byte[1024];

     int byteRead;

     while((byteRead = input.read(buffer)) != -1){
        os.write(buffer,0,byteRead);
     }

     os.flush();

     os.close();

   }

I suspect it is because of multiple use of InputStream, since the code works when I don't invode writeLogInfo(). I am not closing the inputstream anywhere in my code. What am I doing wrong here ?

Answer 1

When you are writing the content to a file, you are reaching the end of the inputstream.

So after that, when you are trying to parse, you get the exception.

You need to use mark and reset methods on the inputstream before passing it to documentbuilder.

Also, first you need to check if the input stream supports mark.

Here is the javadoc, for your reference

http://docs.oracle.com/javase/7/docs/api/java/io/InputStream.html

Answer 2

Are you sure the size of the file is under 1024 bytes. If not why don't you put your "inputstream" to BufferredInputstream, and create the byte array..

BufferedInputStream bin= new BufferedInputStream(new DataInputStream(input));
byte[] buffer= new byte[bin.available()];
bin.read(buffer);
os.write(buffer);
......
......
bin.close();
......