package week03.download.impl;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import week03.download.api.Connection;
import week03.download.api.ConnectionException;
public class ConnectionImpl implements Connection {
HttpURLConnection conn;
URL urlLocation;
public ConnectionImpl(String url) throws ConnectionException {
try {
open(url);
} catch (Exception e) {
e.printStackTrace();
}
}
private void open(String url) throws Exception {
urlLocation = new URL(url);
conn = (HttpURLConnection) urlLocation.openConnection();
}
@Override
public byte[] read(int startPos, int endPos) {
ByteArrayOutputStream baos = null;
try {
HttpURLConnection conn = (HttpURLConnection) urlLocation.openConnection();
conn.setRequestProperty("Range", "bytes="+startPos+"-"+endPos);
InputStream in = conn.getInputStream();
baos = new ByteArrayOutputStream();
int len = 0;
byte[] buffer = new byte[1024];
while((len = in.read(buffer)) != -1){
baos.write(buffer, 0, len);
}
in.close();
baos.close();
} catch (IOException e) {
e.printStackTrace();
}
return baos.toByteArray();
}
@Override
public int getContentLength() {
return conn.getContentLength();
}
@Override
public void close() {
conn.disconnect();
}
}