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<html><head> <title>Apache Lucene API</title></head><body><p>Apache Lucene is a high-performance, full-featured text search engine library.Here's a simple example how to use Lucene for indexing and searching (using JUnitto check if the results are what we expect):</p><!-- ======================================================== --><!-- = Java Sourcecode to HTML automatically converted code = --><!-- = Java2Html Converter 5.0 [2006-02-26] by Markus Gebhard markus@jave.de = --><!-- = Further information: http://www.java2html.de = --><div align="left" class="java"><table border="0" cellpadding="3" cellspacing="0" bgcolor="#ffffff"> <tr> <!-- start source code --> <td nowrap="nowrap" valign="top" align="left"> <code><font color="#ffffff"> </font><font color="#000000">Analyzer analyzer = </font><font color="#7f0055"><b>new </b></font><font color="#000000">StandardAnalyzer</font><font color="#000000">()</font><font color="#000000">;</font><br /><font color="#ffffff"></font><br /><font color="#ffffff"> </font><font color="#3f7f5f">// Store the index in memory:</font><br /><font color="#ffffff"> </font><font color="#000000">Directory directory = </font><font color="#7f0055"><b>new </b></font><font color="#000000">RAMDirectory</font><font color="#000000">()</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#3f7f5f">// To store an index on disk, use this instead (note that the </font><br /><font color="#ffffff"> </font><font color="#3f7f5f">// parameter true will overwrite the index in that directory</font><br /><font color="#ffffff"> </font><font color="#3f7f5f">// if one exists):</font><br /><font color="#ffffff"> </font><font color="#3f7f5f">//Directory directory = FSDirectory.getDirectory("/tmp/testindex", true);</font><br /><font color="#ffffff"> </font><font color="#000000">IndexWriter iwriter = </font><font color="#7f0055"><b>new </b></font><font color="#000000">IndexWriter</font><font color="#000000">(</font><font color="#000000">directory, analyzer, </font><font color="#7f0055"><b>true</b></font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">iwriter.setMaxFieldLength</font><font color="#000000">(</font><font color="#990000">25000</font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">Document doc = </font><font color="#7f0055"><b>new </b></font><font color="#000000">Document</font><font color="#000000">()</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">String text = </font><font color="#2a00ff">"This is the text to be indexed."</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">doc.add</font><font color="#000000">(</font><font color="#7f0055"><b>new </b></font><font color="#000000">Field</font><font color="#000000">(</font><font color="#2a00ff">"fieldname"</font><font color="#000000">, text, Field.Store.YES,</font><br /><font color="#ffffff"> </font><font color="#000000">Field.Index.TOKENIZED</font><font color="#000000">))</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">iwriter.addDocument</font><font color="#000000">(</font><font color="#000000">doc</font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">iwriter.close</font><font color="#000000">()</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><br /><font color="#ffffff"> </font><font color="#3f7f5f">// Now search the index:</font><br /><font color="#ffffff"> </font><font color="#000000">IndexSearcher isearcher = </font><font color="#7f0055"><b>new </b></font><font color="#000000">IndexSearcher</font><font color="#000000">(</font><font color="#000000">directory</font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#3f7f5f">// Parse a simple query that searches for "text":</font><br /><font color="#ffffff"> </font><font color="#000000">QueryParser parser = </font><font color="#7f0055"><b>new </b></font><font color="#000000">QueryParser</font><font color="#000000">(</font><font color="#2a00ff">"fieldname"</font><font color="#000000">, analyzer</font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">Query query = parser.parse</font><font color="#000000">(</font><font color="#2a00ff">"text"</font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">Hits hits = isearcher.search</font><font color="#000000">(</font><font color="#000000">query</font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">assertEquals</font><font color="#000000">(</font><font color="#990000">1</font><font color="#000000">, hits.length</font><font color="#000000">())</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#3f7f5f">// Iterate through the results:</font><br /><font color="#ffffff"> </font><font color="#7f0055"><b>for </b></font><font color="#000000">(</font><font color="#7f0055"><b>int </b></font><font color="#000000">i = </font><font color="#990000">0</font><font color="#000000">; i < hits.length</font><font color="#000000">()</font><font color="#000000">; i++</font><font color="#000000">) {</font><br /><font color="#ffffff"> </font><font color="#000000">Document hitDoc = hits.doc</font><font color="#000000">(</font><font color="#000000">i</font><font color="#000000">)</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">assertEquals</font><font color="#000000">(</font><font color="#2a00ff">"This is the text to be indexed."</font><font color="#000000">, hitDoc.get</font><font color="#000000">(</font><font color="#2a00ff">"fieldname"</font><font color="#000000">))</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">}</font><br /><font color="#ffffff"> </font><font color="#000000">isearcher.close</font><font color="#000000">()</font><font color="#000000">;</font><br /><font color="#ffffff"> </font><font color="#000000">directory.close</font><font color="#000000">()</font><font color="#000000">;</font></code> </td> <!-- end source code --> </tr></table></div><!-- = END of automatically generated HTML code = --><!-- ======================================================== --><p>The Lucene API is divided into several packages:</p><ul><li><b><a href="org/apache/lucene/analysis/package-summary.html">Lucene.Net.Analysis</a></b>defines an abstract <a href="org/apache/lucene/analysis/Analyzer.html">Analyzer</a>API for converting text from a <a href="http://java.sun.com/products/jdk/1.2/docs/api/java/io/Reader.html">java.io.Reader</a>into a <a href="org/apache/lucene/analysis/TokenStream.html">TokenStream</a>,an enumeration of <a href="org/apache/lucene/analysis/Token.html">Token</a>s. A TokenStream is composed by applying <a href="org/apache/lucene/analysis/TokenFilter.html">TokenFilter</a>sto the output of a <a href="org/apache/lucene/analysis/Tokenizer.html">Tokenizer</a>. A few simple implemenations are provided, including <a href="org/apache/lucene/analysis/StopAnalyzer.html">StopAnalyzer</a>and the grammar-based <a href="org/apache/lucene/analysis/standard/StandardAnalyzer.html">StandardAnalyzer</a>.</li><li><b><a href="org/apache/lucene/document/package-summary.html">Lucene.Net.Documents</a></b>provides a simple <a href="org/apache/lucene/document/Document.html">Document</a>class. A document is simply a set of named <a href="org/apache/lucene/document/Field.html">Field</a>s,whose values may be strings or instances of <a href="http://java.sun.com/products/jdk/1.2/docs/api/java/io/Reader.html">java.io.Reader</a>.</li><li><b><a href="org/apache/lucene/index/package-summary.html">Lucene.Net.Index</a></b>provides two primary classes: <a href="org/apache/lucene/index/IndexWriter.html">IndexWriter</a>,which creates and adds documents to indices; and <a href="org/apache/lucene/index/IndexReader.html">IndexReader</a>,which accesses the data in the index.</li><li><b><a href="org/apache/lucene/search/package-summary.html">Lucene.Net.Search</a></b>provides data structures to represent queries (<a href="org/apache/lucene/search/TermQuery.html">TermQuery</a>for individual words, <a href="org/apache/lucene/search/PhraseQuery.html">PhraseQuery</a>for phrases, and <a href="org/apache/lucene/search/BooleanQuery.html">BooleanQuery</a>for boolean combinations of queries) and the abstract <a href="org/apache/lucene/search/Searcher.html">Searcher</a>which turns queries into <a href="org/apache/lucene/search/Hits.html">Hits</a>.<a href="org/apache/lucene/search/IndexSearcher.html">IndexSearcher</a>implements search over a single IndexReader.</li><li><b><a href="org/apache/lucene/queryParser/package-summary.html">Lucene.Net.QueryParsers</a></b>uses <a href="http://javacc.dev.java.net">JavaCC</a> to implement a<a href="org/apache/lucene/queryParser/QueryParser.html">QueryParser</a>.</li><li><b><a href="org/apache/lucene/store/package-summary.html">Lucene.Net.Store</a></b>defines an abstract class for storing persistent data, the <a href="org/apache/lucene/store/Directory.html">Directory</a>,a collection of named files written by an <a href="org/apache/lucene/store/IndexOutput.html">IndexOutput</a>and read by an <a href="org/apache/lucene/store/IndexInput.html">IndexInput</a>. Two implementations are provided, <a href="org/apache/lucene/store/FSDirectory.html">FSDirectory</a>,which uses a file system directory to store files, and <a href="org/apache/lucene/store/RAMDirectory.html">RAMDirectory</a>which implements files as memory-resident data structures.</li><li><b><a href="org/apache/lucene/util/package-summary.html">Lucene.Net.Util</a></b>contains a few handy data structures, e.g., <a href="org/apache/lucene/util/BitVector.html">BitVector</a>and <a href="org/apache/lucene/util/PriorityQueue.html">PriorityQueue</a>.</li></ul>To use Lucene, an application should:<ol><li>Create <a href="org/apache/lucene/document/Document.html">Document</a>s byadding<a href="org/apache/lucene/document/Field.html">Field</a>s;</li><li>Create an <a href="org/apache/lucene/index/IndexWriter.html">IndexWriter</a>and add documents to it with <a href="org/apache/lucene/index/IndexWriter.html#addDocument(Lucene.Net.Documents.Document)">addDocument()</a>;</li><li>Call <a href="org/apache/lucene/queryParser/QueryParser.html#parse(java.lang.String)">QueryParser.parse()</a>to build a query from a string; and</li><li>Create an <a href="org/apache/lucene/search/IndexSearcher.html">IndexSearcher</a>and pass the query to its <a href="org/apache/lucene/search/Searcher.html#search(Lucene.Net.Search.Query)">search()</a>method.</li></ol>Some simple examples of code which does this are:<ul><li> <a href="http://svn.apache.org/repos/asf/lucene/java/trunk/src/demo/org/apache/lucene/demo/FileDocument.java">FileDocument.java</a> containscode to create a Document for a file.</li><li> <a href="http://svn.apache.org/repos/asf/lucene/java/trunk/src/demo/org/apache/lucene/demo/IndexFiles.java">IndexFiles.java</a> creates anindex for all the files contained in a directory.</li><li> <a href="http://svn.apache.org/repos/asf/lucene/java/trunk/src/demo/org/apache/lucene/demo/DeleteFiles.java">DeleteFiles.java</a> deletes someof these files from the index.</li><li> <a href="http://svn.apache.org/repos/asf/lucene/java/trunk/src/demo/org/apache/lucene/demo/SearchFiles.java">SearchFiles.java</a> prompts forqueries and searches an index.</li></ul>To demonstrate these, try something like:<blockquote><tt>> <b>java -cp lucene.jar:lucene-demo.jar Lucene.Net.demo.IndexFiles rec.food.recipes/soups</b></tt><br><tt>adding rec.food.recipes/soups/abalone-chowder</tt><br><tt> </tt>[ ... ]<p><tt>> <b>java -cp lucene.jar:lucene-demo.jar Lucene.Net.demo.SearchFiles</b></tt><br><tt>Query: <b>chowder</b></tt><br><tt>Searching for: chowder</tt><br><tt>34 total matching documents</tt><br><tt>1. rec.food.recipes/soups/spam-chowder</tt><br><tt> </tt>[ ... thirty-four documents contain the word "chowder" ... ]<p><tt>Query: <b>"clam chowder" AND Manhattan</b></tt><br><tt>Searching for: +"clam chowder" +manhattan</tt><br><tt>2 total matching documents</tt><br><tt>1. rec.food.recipes/soups/clam-chowder</tt><br><tt> </tt>[ ... two documents contain the phrase "clam chowder"and the word "manhattan" ... ]<br> [ Note: "+" and "-" are canonical, but "AND", "OR"and "NOT" may be used. ]</blockquote>The <a href="http://svn.apache.org/repos/asf/lucene/java/trunk/src/demo/org/apache/lucene/demo/IndexHTML.java">IndexHTML</a> demo is more sophisticated. It incrementally maintains an index of HTML files, adding new files asthey appear, deleting old files as they disappear and re-indexing filesas they change.<blockquote><tt>> <b>java -cp lucene.jar:lucene-demo.jar Lucene.Net.demo.IndexHTML -create java/jdk1.1.6/docs/relnotes</b></tt><br><tt>adding java/jdk1.1.6/docs/relnotes/SMICopyright.html</tt><br><tt> </tt>[ ... create an index containing all the relnotes ]<p><tt>> <b>rm java/jdk1.1.6/docs/relnotes/smicopyright.html</b></tt><p><tt>> <b>java -cp lucene.jar:lucene-demo.jar Lucene.Net.demo.IndexHTML java/jdk1.1.6/docs/relnotes</b></tt><br><tt>deleting java/jdk1.1.6/docs/relnotes/SMICopyright.html</tt></blockquote></body></html>?? 快捷鍵說明
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