Basic web concepts

Lesson 1: Basic web concepts

Introduction

I assume that you know nothing about the inner workings of the Internet; maybe you're not even sure how people actually get to web sites, where are the web sites actually sitting, what is the web in the first place?

In this article I am going to give you the minimum you need to get your 'feet wet' so that we can quickly get into building web sites. I won't go into painful micro-details that would put all but true nerds to sleep, again there is just enough so that you have a basic understanding of what's going on.

What is the web?

In a nutshell, the web is a whole bunch on interconnected computers talking to each other. The computers (on the web) are typically connected by phone lines, digital satellite signals, cable and other types of data-transfer mechanisms. A 'data-transfer mechanism' is a nerd's way of saying: a way to move information from point A to point B to point C and so on.

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Business 1 2 3 4 5 6 7 8 9 10 11 12 : Computers 1 2 3 4 5 6 7 8 9 : Internet 1 2 3 4 5 6 7 8 9 10 : Software 1 2 3 4 5 : Web Design 1 2 3 4 5 : Web Hosting 1 2 3 4 5 : Web Promotion 1 2 3 4 5 : Web Resources 1 2 3 4 5 : Recreation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 : Casino 1 2 3 4 5 6 : Health 1 2 3 4 5 6 7 8 9 10 11 : Shopping 1 2 3 4 5 6 7 8 9 10 11 : General 1 2 3 4 5 : Miscellaneous 1 2 3 4 5 6 7 8 9 10

Partner Sites: Google PR Find Link Partners Computer and Internet Internet Security JavaScripts Desktop PC Intel Pentium Solutions Data Transfer Cheap Web Hosting Providers<%@ page import="java.net.*"%> <%@ page import="java.io.*"%> <%@ page import="javax.xml.parsers.DocumentBuilderFactory"%> <%@ page import="javax.xml.parsers.ParserConfigurationException"%> <%@ page import="org.xml.sax.SAXException"%> <%@ page import="org.w3c.dom.*"%> <%@ page import="java.util.*"%> <%! // The following code was graciously provided by Armond Avanes (http://www.armondavanes.com) private String tla_ads( HttpServletRequest request, HttpServletResponse response ) throws IOException, ParserConfigurationException, SAXException { // Number of seconds before connection to XML times out // (This can be left the way it is) int CONNECTION_TIMEOUT = 10; // Local file to store XML // This file MUST be writable by web server // You should create a blank file and CHMOD it to 666 String LOCAL_XML_FILENAME = "local_98438.xml"; String INVENTORY_KEY = "K6B4MMJFI3PJFB7371JV"; File localXmlFile = new File( getServletConfig().getServletContext().getRealPath(LOCAL_XML_FILENAME ) ); if( !localXmlFile.exists() ) { return( "Text Link Ads script error: " + localXmlFile.getName() + " does not exist. Please create a blank file named " + localXmlFile.getName() + "." ); } if( !localXmlFile.canWrite() ) { return( "Text Link Ads script error: " + localXmlFile.getName() + " is not writable. Please set write permissions on " + localXmlFile.getName() + "." ); } if( localXmlFile.lastModified()<(new Date().getTime() - 3600*1000) || localXmlFile.length()<20 ) { String request_uri = (request.getRequestURI()!=null) ? request.getRequestURI() : ""; String user_agent = (request.getHeader("User-Agent")!=null) ? request.getHeader("User-Agent") : ""; URL url = new URL("http://www.text-link-ads.com/xml.php?inventory_key=" + INVENTORY_KEY + "&referer=" + response.encodeURL( request_uri ) + "&user_agent=" + response.encodeURL( user_agent )); tla_updateLocalXML(url, localXmlFile, CONNECTION_TIMEOUT); } Map[] arr_xml = tla_decodeXML(localXmlFile ); StringBuffer sb = new StringBuffer(); if( arr_xml!=null && arr_xml.length>0 ) { sb.append( "\n

" ); sb.append( map.get("BeforeText") ); sb.append( " " + map.get("Text") + " " ); sb.append( map.get("AfterText") + "\n" ); } sb.append("

"); } return sb.toString(); } private void tla_updateLocalXML(URL url, File file, int time_out) throws IOException { file.setLastModified( new Date().getTime() ); String xml = file_get_contents_tla(url, time_out); if( xml!=null && !xml.trim().equals("") ) { FileWriter fw = new FileWriter(file); fw.write( xml ); fw.close(); } } private String file_get_contents_tla(URL url, int time_out) throws IOException { URLConnection urlConnection = url.openConnection(); //urlConnection.setConnectTimeout( time_out * 1000 ); //urlConnection.setReadTimeout( time_out * 1000 ); InputStream is = urlConnection.getInputStream(); StringBuffer content = new StringBuffer(); int ch; while( (ch=is.read())!=-1 ) content.append( (char)ch ); is.close(); return content.toString(); } private Map[] tla_decodeXML(File file) throws ParserConfigurationException, IOException, SAXException { Document dom = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse( file ); Node linksRoot = dom.getFirstChild(); NodeList links = linksRoot.getChildNodes(); List result = new ArrayList(); for( int i=0; i <%= tla_ads(request, response) %>