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GetResponse.java
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/*
* Author: Havard Rast Blok
* E-mail: 
* Web : www.rememberjava.com
*/
import java.io.*;
import java.net.*;
/**
* Checks to see if the URL can be found on the server, or if it
* returns a 404 file not found message.
*
* Refer to the main() method for how to read a local file instead.
*/
public class GetResponse
{
private static String startTag = "<title>";
private static String endTag = "</title>";
private static String msg404 = "404";
private static int startTagLength = startTag.length();
public GetResponse( URL theURL )
{
BufferedReader bufReader;
String line;
boolean foundStartTag = false;
boolean foundEndTag = false;
boolean found404 = false;
int startIndex, endIndex;
String title = "";
try
{
//open file
bufReader = new BufferedReader( new InputStreamReader(theURL.openStream()) );
//read line by line
while( (line = bufReader.readLine()) != null && !foundEndTag && !found404)
{
//System.out.println(line);
//search for line containing 404
if( line.toLowerCase().indexOf(msg404) != -1 )
{
System.out.println( "Found 404 line. This URL was not found on the server" );
found404 = true;
}
//search for title start tag (convert to lower case before searhing)
if( !foundStartTag && (startIndex = line.toLowerCase().indexOf(startTag)) != -1 )
{
foundStartTag = true;
}
else
{
//else copy from start of string
startIndex = -startTagLength;
}
//search for title end tag (convert to lower case before searhing)
if( foundStartTag && (endIndex = line.toLowerCase().indexOf(endTag)) != -1 )
{
foundEndTag = true;
}
else
{
//else copy to end of string
endIndex = line.length();
}
//extract title field
if( foundStartTag || foundEndTag )
{
title += line.substring( startIndex + startTagLength, endIndex );
}
}
//close the file when finished
bufReader.close();
//output the title
if( title.length() > 0 )
{
System.out.println("Title: "+title);
}
else
{
System.out.println("No title found in document.");
}
}
catch( IOException e )
{
System.out.println( "GetResponse.GetResponse - error opening or reading URL: " + e );
}
}
public static void main( String args[] )
{
try
{
new GetResponse(new URL(args[0]));
//Open file from disk instead
//File f = new File( args[0] );
//new GetResponse( f.toURL() );
}
catch (MalformedURLException e)
{
System.out.println("GetResponse.main - wrong url: " +e );
}
}
}
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