Save binary file from URL : URL « Network « Java Tutorial

1. Java Tutorial
2. Network
3. URL

import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;

public class MainClass {

  public static void main(String args[]) throws Exception {

    URL u = new URL("http://www.java2s.com/binary.dat");
    URLConnection uc = u.openConnection();
    String contentType = uc.getContentType();
    int contentLength = uc.getContentLength();
    if (contentType.startsWith("text/") || contentLength == -1) {
      throw new IOException("This is not a binary file.");
    }
    InputStream raw = uc.getInputStream();
    InputStream in = new BufferedInputStream(raw);
    byte[] data = new byte[contentLength];
    int bytesRead = 0;
    int offset = 0;
    while (offset < contentLength) {
      bytesRead = in.read(data, offset, data.length - offset);
      if (bytesRead == -1)
        break;
      offset += bytesRead;
    }
    in.close();

    if (offset != contentLength) {
      throw new IOException("Only read " + offset + " bytes; Expected " + contentLength + " bytes");
    }

    String filename = u.getFile().substring(filename.lastIndexOf('/') + 1);
    FileOutputStream out = new FileOutputStream(filename);
    out.write(data);
    out.flush();
    out.close();
  }
}