天空是蓝色的

String url = "http://www.digitalcq.com/",
   proxy = "proxy.digitalcq.com",
   port = "8080";
URL server = new URL(url);
Properties systemProperties = System.getProperties();
systemProperties.setProperty("http.proxyHost",proxy);
systemProperties.setProperty("http.proxyPort",port);
HttpURLConnection connection = (
    HttpURLConnection)server.openConnection();
connection.connect();
InputStream in = connection.getInputStream();
readResponse(in);

public class SimpleAuthenticator
   extends Authenticator
{
   private String username,
                  password;
    public SimpleAuthenticator(String username,String password)
   {
      this.username = username;
      this.password = password;
   }
    protected PasswordAuthentication getPasswordAuthentication()
   {
      return new PasswordAuthentication(
             username,password.toCharArray());
   }
}

String url = "http://www.digitalcq.com/",
       proxy = "proxy.digitalcq.com",
       port = "8080",
       username = "usr",
       password = "pwd";
Authenticator.setDefault(new SimpleAuthenticator(
       username,password));
URL server = new URL(url);
Properties systemProperties = System.getProperties();
systemProperties.setProperty("http.proxyHost",proxy);
systemProperties.setProperty("http.proxyPort",port);
HttpURLConnection connection = (
    HttpURLConnection)server.openConnection();
connection.connect();
InputStream in = connection.getInputStream();
readResponse(in);

String url = "http://www.digitalcq.com/",
       proxy = "proxy.digitalcq.com",
       port = "8080",
       authentication = "usr:pwd";
URL server = new URL(url);
Socket socket = new Socket(proxy,port);
Writer writer = new OutputStreamWriter(socket.getOutputStream(),
                                       "US-ASCII");
writer.write("GET " + server.toExternalForm() + " HTTP/1.0\r\n");
writer.write("Host: " + server.getHost() + "\r\n");
writer.write("Proxy-Authorization: Basic "
             + new sun.misc.BASE64Encoder().encode(
               authentication.getBytes())
             + "\r\n\r\n");
writer.flush();
BufferedReader reader = new BufferedReader(new InputStreamReader(
                            socket.getInputStream(),"US-ASCII"));
String line = reader.readLine();
if(line != null && line.startsWith("HTTP/"))
{
   int sp = line.indexOf(' ');
   String status = line.substring(sp + 1,sp + 4);
   if(status.equals("200"))
   {
      while(line.length() != 0)
         line = reader.readLine();
      readResponse(reader);
   }
   else
      throw new FileNotFoundException("Host reports error " +
                                       status);
}
else
   throw new IOException("Bad protocol");
reader.close();
writer.close();
socket.close();