How to download data from url?

Question

I can download data via HttpUrlConnection and InputStream but I need to download raw-data. So, i want to create a DownloadManager via raw-data, then using raw-data I convert this data to binary or image format. According to my research, I see "download file from url" but I can't download file in mac? Always, I get FileNotFoundException. Please help me. How I can download data from url?

public class DownloadData extends AsyncTask<Void,Void,Void> {
@Override
protected Void doInBackground(Void... params) {

    try {
        downloadData("https://blablalabla/get");
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}

public void downloadData(String myurl) throws IOException {
    URL u = new URL(myurl);
    InputStream is = u.openStream();

    DataInputStream dis = new DataInputStream(is);

    byte[] buffer = new byte[1024];
    int length;

    OutputStream fos = new FileOutputStream(new File(Environment.getExternalStorageDirectory() + "/Users/ilknurpc/Desktop/text.docx"));
    while ((length = dis.read(buffer))>0) {
        fos.write(buffer, 0, length);
    }


}
}

Please show at least the relevant excerpts of your code. – Fang Jun 17 '16 at 07:22 — Fang, Jun 17 '16 at 07:22

score 0 · Answer 1 · answered Jun 17 '16 at 07:36

If you want to construct a workable download manager, I would suggest that you take a look at the Tomcat Default Servlet Implementation .

There a few number of HTTP headers that you need to understand such as E-Tags and Http Range Headers for a proper implementation.

Thankfully the Tomcat Default Servlet handles the prerequisites for you.

You can adapt this servlet in your code with minor changes (package declaration etc).

How to download data from url?

1 Answers1