Apache Lucene 3.1 发布

Apache Lucene 3.1 发布了！该版本修复了很多bug,性能得到了很大优化，包含诸多新亮点功能。

txtLucene是一套用于全文检索和搜寻的开源程式库，由Apache软件基金会支持和提供。Lucene提供了一个简单又强大的应用程式接口，能够做全文索引和搜寻，在Java开发环境里Lucene是一个成熟的免费开放源代码工具;就其本身而论，Lucene是现在并且是这几年，最受欢迎的免费java资讯检索程式库。

该版本新亮点：

* Numerous performance improvements: faster exact PhraseQuery; merging favors segments with deletions; primary key lookup is faster; IndexWriter.addIndexes(Directory[]) uses file copy instead of merging; various Directory performance improvements; compound file is dynamically turned off for large segments; fully deleted segments are dropped on commit; faster snowball analyzers (in contrib); ConcurrentMergeScheduler is more careful about setting priority of merge threads.

* ReusableAnalyzerBase makes it easier to reuse TokenStreams correctly.

* Improved Analysis capabilities: Improved Unicode support, including Unicode 4, more friendly term handling (CharTermAttribute), easier object reuse and better support for protected words in lossy token filters (e.g. stemmers).

* ConstantScoreQuery now allows directly wrapping a Query.

* IndexWriter is now configured with a new separate builder API,
IndexWriterConfig.  You can now control IndexWriter's previously
fixed internal thread limit by calling setMaxThreadStates.

* IndexWriter.getReader is replaced by IndexReader.open(IndexWriter). In addition you can now specify whether deletes should be resolved when you open an NRT reader.

* MultiSearcher is deprecated; ParallelMultiSearcher has been
absorbed directly into IndexSearcher.

* On 64bit Windows and Solaris JVMs, MMapDirectory is now the
default implementation (returned by FSDirectory.open). MMapDirectory also enables unmapping if the JVM supports it.

* New TotalHitCountCollector just counts total number of hits.

* ReaderFinishedListener API enables external caches to evict entries once a segment is finished.

下载地址：http://www.apache.org/dyn/closer.cgi/lucene/java