Lecture 9: Network programming

Manipulating URLs URL is an acronym for Uniform Resource Locator and is a reference (an address) to a resource on the Internet. Sample structure of a URL. The resource name part may contain: host name, file | Lecture 9: Network programming Manipulating URLs URL is an acronym for Uniform Resource Locator and is a reference (an address) to a resource on the Internet. Sample structure of a URL. The resource name part may contain: host name, file name, port number(optional) and reference (optional) you can create a URL object in Java from an absolute URL or a relative URL. The URL class provides several methods implemented on URL objects. You can get the protocol, host name, port number, and filename from a URL. Protocol Identifier Resource Name Example code import .*; import .*; public class ParseURL { public static void main(String[] args) throws Exception { URL aURL = new URL("" + "tutorial/"); ("protocol = " + ()); ("host = " + ()); ("filename = " + ()); ("port = " + ()); ("ref = " + ()); } } Output of the above code: protocol = http host = filename = /docs/books/tutorial/ port = 80 ref = DOWNLOADING Connecting with a URL (1) openStream(): returns a object, from which you can read easily as reading from an input stream. It may throw an IOException Example code import .*; import .*; public class ReadURL { public static void main(String[] args) throws Exception { URL osu = new URL(""); BufferedReader in = new BufferedReader( new InputStreamReader(())); String inputLine; while ((inputLine = ()) != null) (inputLine); (); } } This prints out the source code for the webpage Connecting with a URL (2) openConnection(): Returns a URLConnection object that represents a connection to the remote object referred to by the URL. It may throws an IOException try { URL osu = new . | Lecture 9: Network programming Manipulating URLs URL is an acronym for Uniform Resource Locator and is a reference (an address) to a resource on the Internet. Sample structure of a URL. The resource name part may contain: host name, file name, port number(optional) and reference (optional) you can create a URL object in Java from an absolute URL or a relative URL. The URL class provides several methods implemented on URL objects. You can get the protocol, host name, port number, and filename from a URL. Protocol Identifier Resource Name Example code import .*; import .*; public class ParseURL { public static void main(String[] args) throws Exception { URL aURL = new URL("" + "tutorial/"); ("protocol = " + ()); ("host = " + ()); ("filename = " + ()); ("port = " + ()); .