<%@ page import = " javax.servlet.*, javax.servlet.http.*, java.io.*, org.apache.lucene.analysis.*, org.apache.lucene.analysis.standard.StandardAnalyzer, org.apache.lucene.document.*, org.apache.lucene.index.*, org.apache.lucene.store.*, org.apache.lucene.search.*, org.apache.lucene.queryParser.*, org.apache.lucene.demo.*, org.apache.lucene.demo.html.Entities, java.net.URLEncoder, org.apache.lucene.util.Version" %>
<%
/*
Author: Andrew C. Oliver, SuperLink Software, Inc. (acoliver2@users.sourceforge.net)
This jsp page is deliberatly written in the horrible java directly embedded
in the page style for an easy and concise demonstration of Lucene.
Due note...if you write pages that look like this...sooner or later
you'll have a maintenance nightmare. If you use jsps...use taglibs
and beans! That being said, this should be acceptable for a small
page demonstrating how one uses Lucene in a web app.
This is also deliberately overcommented. ;-)
*/
%>
<%!
public String escapeHTML(String s) {
s = s.replaceAll("&", "&");
s = s.replaceAll("<", "<");
s = s.replaceAll(">", ">");
s = s.replaceAll("\"", """);
s = s.replaceAll("'", "'");
return s;
}
%>
<%@include file="header.jsp"%>
<%
boolean error = false; //used to control flow for error messages
String indexName = indexLocation; //local copy of the configuration variable
IndexSearcher searcher = null; //the searcher used to open/search the index
Query query = null; //the Query created by the QueryParser
TopDocs hits = null; //the search results
int startindex = 0; //the first index displayed on this page
int maxpage = 50; //the maximum items displayed on this page
String queryString = null; //the query entered in the previous page
String startVal = null; //string version of startindex
String maxresults = null; //string version of maxpage
int thispage = 0; //used for the for/next either maxpage or
//hits.totalHits - startindex - whichever is
//less
try {
IndexReader reader = IndexReader.open(FSDirectory.open(new File(indexName)), true); // only searching, so read-only=true
searcher = new IndexSearcher(reader); //create an indexSearcher for our page
//NOTE: this operation is slow for large
//indices (much slower than the search itself)
//so you might want to keep an IndexSearcher
//open
} catch (Exception e) { //any error that happens is probably due
//to a permission problem or non-existant
//or otherwise corrupt index
%>
ERROR opening the Index - contact sysadmin!
Error message: <%=escapeHTML(e.getMessage())%>
<% error = true; //don't do anything up to the footer
}
%>
<%
if (error == false) { //did we open the index?
queryString = request.getParameter("query"); //get the search criteria
startVal = request.getParameter("startat"); //get the start index
maxresults = request.getParameter("maxresults"); //get max results per page
try {
maxpage = Integer.parseInt(maxresults); //parse the max results first
startindex = Integer.parseInt(startVal); //then the start index
} catch (Exception e) { } //we don't care if something happens we'll just start at 0
//or end at 50
if (queryString == null)
throw new ServletException("no query "+ //if you don't have a query then
"specified"); //you probably played on the
//query string so you get the
//treatment
Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT); //construct our usual analyzer
try {
QueryParser qp = new QueryParser("contents", analyzer);
query = qp.parse(queryString); //parse the
} catch (ParseException e) { //query and construct the Query
//object
//if it's just "operator error"
//send them a nice error HTML
%>
Error while parsing query: <%=escapeHTML(e.getMessage())%>
<%
error = true; //don't bother with the rest of
//the page
}
}
%>
<%
if (error == false && searcher != null) { // if we've had no errors
// searcher != null was to handle
// a weird compilation bug
thispage = maxpage; // default last element to maxpage
hits = searcher.search(query, maxpage); // run the query
if (hits.totalHits == 0) { // if we got no results tell the user
%>
I'm sorry I couldn't find what you were looking for.
<%
error = true; // don't bother with the rest of the
// page
}
}
if (error == false && searcher != null) {
%>
| Document |
Summary |
<%
if ((startindex + maxpage) > hits.totalHits) {
thispage = hits.totalHits - startindex; // set the max index to maxpage or last
} // actual search result whichever is less
for (int i = startindex; i < (thispage + startindex); i++) { // for each element
%>
<%
Document doc = searcher.doc(hits.scoreDocs[i].doc); //get the next document
String doctitle = doc.get("title"); //get its title
String url = doc.get("path"); //get its path field
if (url != null && url.startsWith("../webapps/")) { // strip off ../webapps prefix if present
url = url.substring(10);
}
if ((doctitle == null) || doctitle.equals("")) //use the path if it has no title
doctitle = url;
//then output!
%>
| <%=doctitle%> |
<%=doc.get("summary")%> |
<%
}
%>
<% if ( (startindex + maxpage) < hits.totalHits) { //if there are more results...display
//the more link
String moreurl="results.jsp?query=" +
URLEncoder.encode(queryString) + //construct the "more" link
"&maxresults=" + maxpage +
"&startat=" + (startindex + maxpage);
%>
| More Results>> |
<%
}
%>
<% } //then include our footer.
if (searcher != null)
searcher.close();
%>
<%@include file="footer.jsp"%>