UCDemo.java

Java documentation URLConnection class

// Demonstrate URLConnection.
import java.net.*;
import java.io.*;
import java.util.*;

class UCDemo
{

public static void open(String str) {
    InputStream in = null;
    URLConnection connection = null;

    try {
      URL url = new URL(str);

      connection = url.openConnection();

      // get date
      long d = connection.getDate();
      if(d==0)
        System.out.println("No date information.");
      else
        System.out.println("Date: " + new Date(d));

      // get content type
      System.out.println("Content-Type: " +
                          connection.getContentType());

      // get expiration date
      d = connection.getExpiration();
      if(d==0)
        System.out.println("No expiration information.");
      else
        System.out.println("Expires: " + new Date(d));

      // get last-modified date
      d = connection.getLastModified();
      if(d==0)
        System.out.println("No last-modified information.");
      else
        System.out.println("Last-Modified: " + new Date(d));

      // get content length
      int len = connection.getContentLength();
      if(len == -1)
        System.out.println("Content length unavailable.");
      else
        System.out.println("Content-Length: " + len);

      if(len != 0) {
        System.out.println("=== Content ===");
        in = connection.getInputStream();

        int ch;
        while (((ch = in.read()) != -1)) {
          System.out.print((char) ch);
        }
      } else {
        System.out.println("No content available.");
      }
    } catch(IOException exc) {
      System.out.println("Connection Error: " + exc);
    } finally {
      try {
        if(in != null) in.close();
      } catch(IOException exc) {
        System.out.println("Error closing connection: " + exc);
      }
    }
  }
  public static void main(String[] args) {
	open("https://johnloomis.org/ece538");
  }
}

Results

Date: Wed Nov 14 14:36:27 EST 2012
Content-Type: text/html
No expiration information.
Last-Modified: Thu Oct 11 15:57:51 EDT 2012
Content-Length: 1290
=== Content ===
Content found here ...

Reference

Maintained by John Loomis, updated Wed Nov 14 14:36:42 2012