Code sample: Retrieving a web page using the GCF
This code sample uses the BlackBerry® Mobile Data System transport. To make this code sample as generic as possible, the InputConnection and OutputConnection interfaces are used in place of the HttpConnection interface.
import net.rim.device.api.ui.component.RichTextField;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.UiApplication;
import java.io.*;
import javax.microedition.io.*;
public class NetworkSample extends UiApplication
{
public static void main(String[] args)
{
NetworkSample app = new NetworkSample();
app.enterEventDispatcher();
}
public NetworkSample() {
new HTTPConnectionSetup();
}
}
class HTTPConnectionSetup
{
public HTTPConnectionSetup()
{
Thread t = new Thread(new Runnable()
{
public void run() {
Connection c = null;
try
{
c = Connector.open("http://www.blackberry.com;deviceside=false");
} catch (IOException e) {
e.printStackTrace();
}
if(c != null)
{
displayContent(c);
}
}
});
t.start();
}
private void displayContent(final Connection c) {
// When the connection thread completes, show the data from the web server
UiApplication.getUiApplication().invokeLater(new Runnable()
{
public void run() {
UiApplication.getUiApplication().pushScreen(new HTTPOutputScreen(c));
}
});
}
}
class HTTPOutputScreen extends MainScreen
{
RichTextField _rtfOutput = new RichTextField();
public HTTPOutputScreen(Connection conn)
{
// Create a container for the data, and put it on the screen
_rtfOutput.setText("Retrieving data. Please wait...");
add(_rtfOutput);
// Retrieve the data from the web server, using the connection, on a
// separate thread
ContentReaderThread t = new ContentReaderThread(conn);
t.start();
}
// After the data has been retrieved, display it
public void showContents(final String result)
{
UiApplication.getUiApplication().invokeLater(new Runnable()
{
public void run()
{
_rtfOutput.setText(result);
}
});
}
private final class ContentReaderThread extends Thread
{
private Connection _connection;
ContentReaderThread(Connection conn)
{
_connection = conn;
}
public void run()
{
String result = "";
OutputStream os = null;
InputStream is = null;
try
{
// Send HTTP GET to the server
OutputConnection outputConn = (OutputConnection) _connection;
os = outputConn.openOutputStream();
String getCommand = "GET " + "/" + " HTTP/1.0\r\n\r\n";
os.write(getCommand.getBytes());
os.flush();
// Get InputConnection and read the server's response
InputConnection inputConn = (InputConnection) _connection;
is = inputConn.openInputStream();
byte[] data = net.rim.device.api.io.IOUtilities.streamToBytes(is);
result = new String(data);
// is.close();
}
catch(Exception e)
{
result = "ERROR fetching content: " + e.toString();
}
finally
{
// Close OutputStream
if(os != null)
{
try
{
os.close();
}
catch(IOException e)
{
}
}
// Close InputStream
if(is != null)
{
try
{
is.close();
}
catch(IOException e)
{
}
}
// Close Connection
try
{
_connection.close();
}
catch(IOException ioe)
{
}
}
// Show the response received from the web server, or an error message
showContents(result);
}
}
}
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