The basic setup of decorators is like this: InputStream fileStream = new FileInputStream(filename); InputStream gzipStream = new GZIPInputStream(fileStream); Reader decoder = new InputStreamReader(gzipStream, encoding); BufferedReader buffered = new BufferedReader(decoder); The key issue in this snippet is the value of encoding. This is the character encoding of the text in the file. Is it “US-ASCII”, “UTF-8”, … Read more
FileReader API is asynchronous so you should handle it with block calls. A for loop wouldn’t do the trick since it wouldn’t wait for each read to complete before reading the next chunk. Here’s a working approach. function parseFile(file, callback) { var fileSize = file.size; var chunkSize = 64 * 1024; // bytes var offset … Read more
Faced a similar problem and its true the ‘reader.result’ doesn’t end up as ‘byte[]’. So I have cast it to Uint8Array object. This too is not a perfect ‘byte[]’ ,so I had to create a ‘byte[]’ from it. Here is my solution to this problem and it worked well for me. var reader = new … Read more
I think the cleanest solution would be to change the base64 encoder to operate directly on a Uint8Array instead of a string. Important: You’ll need to set the binaryType of the web socket to “arraybuffer” for this. The onmessage method should look like this: socket.onmessage = function(msg) { var arrayBuffer = msg.data; var bytes = … Read more
The problem is you’re running the loop now but the callbacks you are setting are getting run later (when the events fire). By the time they run, the loop is over and remains at whatever the last value was. So it will always show “file2” in your case for the name. The solution is to … Read more
I would start with closing reader, and flushing writer: public class FileReplace { List<String> lines = new ArrayList<String>(); String line = null; public void doIt() { try { File f1 = new File(“d:/new folder/t1.htm”); FileReader fr = new FileReader(f1); BufferedReader br = new BufferedReader(fr); while ((line = br.readLine()) != null) { if (line.contains(“java”)) line = … Read more
It sounds like your code is I/O bound. This means that multiprocessing isn’t going to help—if you spend 90% of your time reading from disk, having an extra 7 processes waiting on the next read isn’t going to help anything. And, while using a CSV reading module (whether the stdlib’s csv or something like NumPy … Read more
My problem was that I assumed FileReader was sychronous. Here is the right way to do it. If you are on chrome, this code has to be running on a server (localhost or on a site). It won’t work with a local file. <!doctype html> <html> <script> function handle_files(files) { for (i = 0; i … Read more
We modified midos answer to get it to work the following: function readFile(file){ return new Promise((resolve, reject) => { var fr = new FileReader(); fr.onload = () => { resolve(fr.result ) }; fr.onerror = reject; fr.readAsText(file.blob); }); }
(Following is a late but complete answer) FileReader methods support FileReader.readAsBinaryString() is deprecated. Don’t use it! It’s no longer in the W3C File API working draft: void abort(); void readAsArrayBuffer(Blob blob); void readAsText(Blob blob, optional DOMString encoding); void readAsDataURL(Blob blob); NB: Note that File is a kind of extended Blob structure. Mozilla still implements readAsBinaryString() … Read more