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POJava regex pattern matcher - how to allow a choice?
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copied!<p>In Java I have a block of code that processes an Apache web server log, and checks the URL extension type. It works well when the URL is in the format "/index.html", but occasionally the URL is "/", which breaks the code.</p> <p>The below code works fine, but if in the input line "/index.html" is changed to "/" then it will break because line 19 <code>(\\.\\S*)</code> checks for a dot followed by a few characters, but if the URL is "/" there is no dot for the regex to find.</p> <p>How can I rewrite line 19 <code>(\\.\\S*)</code> to allow for a choice of .extension or "/"?</p> <p>In other words: <br> if URL=index.html, then extension is .html <br> if URL=index.php, then extension is .php <br> if URL=/, then extension is "" <br></p> <pre><code>import java.util.regex.*; public class Test { public static void main(String[] args) { String log_input = "123.45.67.89 - - [27/Oct/2000:09:27:09 -0400] \"GET /index.html HTTP/1.0\" 200 10450 \"-\" \"Mozilla/4.6 [en] (X11; U; OpenBSD 2.8 i386; Nav)\""; //String log_input = "123.45.67.89 - - [27/Oct/2000:09:27:09 -0400] \"GET / HTTP/1.0\" 200 10450 \"-\" \"Mozilla/4.6 [en] (X11; U; OpenBSD 2.8 i386; Nav)\""; //step 1 - split log line Pattern p = Pattern.compile("^([\\d.]+) (\\S+) (\\S+) \\[([\\w:/]+\\s[+\\-]\\d{4})\\] \"(.+)\" (\\d{3}) (\\d+) \"([^\"]+)\" \"([^\"]+)\""); Matcher m = p.matcher(log_input); m.matches(); String request_ip = m.group(1); String request_resource = m.group(5); System.out.println("Input: " + m.group(5)); //step 2 - check file extension Pattern p2 = Pattern.compile(".* .*(\\.\\S*) .*"); Matcher m2 = p2.matcher(request_resource); m2.matches(); String request_resource_ext = m2.group(1); System.out.println("Extension: " + request_resource_ext); if(request_resource_ext.matches("\\.htm|\\.html|\\.php|^$")){ //^$ in case the URL is / which has no extension System.out.println("Write"); }else{ System.out.println("Do not write"); } } } </code></pre>

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