A Web Page Source Viewer : HttpURLConnection « Network « Java Tutorial

1. Java Tutorial
2. Network
3. HttpURLConnection

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class Main extends JFrame {
  JButton go = new JButton("Get Source");

  JTextArea codeArea = new JTextArea();

  public Main() {
    JPanel inputPanel = new JPanel(new BorderLayout(3, 3));
    go.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
          URL pageURL = new URL("http://www.google.com");
          HttpURLConnection urlConnection = (HttpURLConnection) pageURL.openConnection();
          int respCode = urlConnection.getResponseCode();
          String response = urlConnection.getResponseMessage();
          codeArea.setText("HTTP/1.x " + respCode + " " + response + "\n");
          int count = 1;
          while (true) {
            String header = urlConnection.getHeaderField(count);
            String key = urlConnection.getHeaderFieldKey(count);
            if (header == null || key == null) {
              break;
            }
            codeArea.append(urlConnection.getHeaderFieldKey(count) + ": " + header + "\n");
            count++;
          }
          InputStream in = new BufferedInputStream(urlConnection.getInputStream());
          Reader r = new InputStreamReader(in);
          int c;
          while ((c = r.read()) != -1) {
            codeArea.append(String.valueOf((char) c));
          }
          codeArea.setCaretPosition(1);
        } catch (Exception ee) {
        }
      }
    });
    inputPanel.add(BorderLayout.EAST, go);
    JScrollPane codeScroller = new JScrollPane(codeArea);
    add(BorderLayout.NORTH, inputPanel);
    add(BorderLayout.CENTER, codeScroller);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setSize(700, 500);
    this.setVisible(true);
  }

  public static void main(String[] args) {
    JFrame webPageSourceViewer = new Main();
  }
}