import java.net.*;
import java.io.*;


public class robot{
public static void main(String[] arg){
int character;
BufferedInputStream bin;
try{
if(arg[0]!=null&&arg[0].length()>0){
URL url = new URL(/tech-qa-java/arg[0]/index.html);
bin = (BufferedInputStream)url.getContent();
while((character = bin.read())>0)
System.out.print((char)character);
System.out.println();
}
}catch(MalformedURLException ex){
System.err.println("MalformedURLException: "+ex.getMessage());
}catch(IOException ex){
System.err.println("IOException: "+ex.getMessage());
}
}
}

编译通过，但运行时出错：
Exception in thread "main" java.lang.ClassCastException
    at robot.main(Compiled Code)

String theCGI = "http://www.server.com/cgi-bin/aCGI.pl";
String encoded = "name=" + URLencoder.encode("Real Gagnon");
URL CGIurl = new URL(/tech-qa-java/theCGI/index.html);

URLConnection c = CGIurl.openConnection();
c.setDoOutput(true);
c.setUseCaches(false);
c.setRequestProperty("content-type","application/x-www-form-urlencoded");
DataOutputStream out = new DataOutputStream(c.getOutputStream());
out.writeBytes(encoded);
out.flush(); out.close();

BufferedReader in =
   new BufferedReader(new InputStreamReader(c.getInputStream());

String aLine;
while ((aLine = in.readLine()) != null) {
   // data from the CGI
   System.out.println(aLine);
   }

URL myURL = new URL(/tech-qa-java/strURL/index.html);
URLConnection conn = myURL.openConnection();    
InputStream inputs = conn.getInputStream();

http://www.csdn.net/develop/read_article.asp?id=7635

ender是对的，我写错了。:)