Java/Development Class/Parser

Parse an Apache log file with Regular Expressions

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.util.regex.*; /**

* Common fields for Apache Log demo.
*/

interface LogExample {

 /** The number of fields that must be found. */
 public static final int NUM_FIELDS = 9;
 /** The sample log entry to be parsed. */
 public static final String logEntryLine = "123.45.67.89 - - [27/Oct/2000:09:27:09 -0400] \"GET /java/javaResources.html HTTP/1.0\" 200 10450 \"-\" \"Mozilla/4.6 [en] (X11; U; OpenBSD 2.8 i386; Nav)\"";

}

/**

* Parse an Apache log file with Regular Expressions
*/

public class LogRegExp implements LogExample {

 public static void main(String argv[]) {
   String logEntryPattern = "^([\\d.]+) (\\S+) (\\S+) \\[([\\w:/]+\\s[+\\-]\\d{4})\\] \"(.+?)\" (\\d{3}) (\\d+) \"([^\"]+)\" \"([^\"]+)\"";
   System.out.println("Using RE Pattern:");
   System.out.println(logEntryPattern);
   System.out.println("Input line is:");
   System.out.println(logEntryLine);
   Pattern p = Pattern.rupile(logEntryPattern);
   Matcher matcher = p.matcher(logEntryLine);
   if (!matcher.matches() || 
     NUM_FIELDS != matcher.groupCount()) {
     System.err.println("Bad log entry (or problem with RE?):");
     System.err.println(logEntryLine);
     return;
   }
   System.out.println("IP Address: " + matcher.group(1));
   System.out.println("Date&Time: " + matcher.group(4));
   System.out.println("Request: " + matcher.group(5));
   System.out.println("Response: " + matcher.group(6));
   System.out.println("Bytes Sent: " + matcher.group(7));
   if (!matcher.group(8).equals("-"))
     System.out.println("Referer: " + matcher.group(8));
   System.out.println("Browser: " + matcher.group(9));
 }

}

      </source>