Lucene分词器及高亮
分词器
在lucene中我们按照分词方式把文档进行索引，不同的分词器索引的效果不太一样，之前的例子使用的都是标准分词器，对于英文的效果很好，但是中文分词效果就不怎么样，他会按照汉字的字直接分词，没有词语的概念。
使用分词的地方只需要把Analyzer实例化成我们第三方的分词器即可
中文分词有很多，这里使用IKAnalyzer 为例，
下载地址 https://git.oschina.net/wltea/IK-Analyzer-2012FF 现在下来后里面有一篇教程。
高亮
导入lucene-highlighter-xxx.jar 在对查询出来的结果实现高亮显示
// 关键字高亮显示的html标签，需要导入lucene-highlighter-xxx.jar
SimpleHTMLFormatter simpleHTMLFormatter = new SimpleHTMLFormatter("<span style='color:red'>", "</span>");
Highlighter highlighter = new Highlighter(simpleHTMLFormatter, new QueryScorer(query));
for (int i = 0; i < hits.length; i++) {
Document doc = isearcher.doc(hits[i].doc);
// 内容增加高亮显示
TokenStream tokenStream = analyzer.tokenStream("content", new StringReader(doc.get("content")));
String content = highlighter.getBestFragment(tokenStream, doc.get("content")); System.out.println(content);
}
Lucene中文分词器
package lucene_demo04;
import java.io.IOException;
import java.io.StringReader;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.queryparser.classic.ParseException;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.QueryWrapperFilter;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.highlight.Highlighter;
import org.apache.lucene.search.highlight.InvalidTokenOffsetsException;
import org.apache.lucene.search.highlight.QueryScorer;
import org.apache.lucene.search.highlight.SimpleHTMLFormatter;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;
import org.wltea.analyzer.lucene.IKAnalyzer;
/**
* 中文分词，IKAnalayzer,对索引结果实现高亮显示
*
* @author YipFun
*/
public class LuceneDemo04
{
private static final Version version = Version.LUCENE_4_9;
private Directory directory = null;
private DirectoryReader ireader = null;
private IndexWriter iwriter = null;
private IKAnalyzer analyzer;
// 测试数据
private String[] content = { "你好，我是中共人", "中华人民共和国", "中国人民从此站起来了", "Lucene是一个不错的全文检索的工具", "全文检索中文分词" };
/**
* 构造方法
*/
public LuceneDemo04()
{
directory = new RAMDirectory();
}
private IKAnalyzer getAnalyzer()
{
if (analyzer == null)
{
return new IKAnalyzer();
} else
{
return analyzer;
}
}
/**
* 创建索引
*/
public void createIndex()
{
Document doc = null;
try
{
IndexWriterConfig iwConfig = new IndexWriterConfig(version, getAnalyzer());
iwConfig.setOpenMode(OpenMode.CREATE_OR_APPEND);
iwriter = new IndexWriter(directory, iwConfig);
for (String text : content)
{
doc = new Document();
doc.add(new TextField("content", text, Field.Store.YES));
iwriter.addDocument(doc);
}
} catch (IOException e)
{
e.printStackTrace();
} finally
{
try
{
if (iwriter != null)
iwriter.close();
} catch (IOException e)
{
e.printStackTrace();
}
}
}
public IndexSearcher getSearcher()
{
try
{
if (ireader == null)
{
ireader = DirectoryReader.open(directory);
} else
{
DirectoryReader tr = DirectoryReader.openIfChanged(ireader);
if (tr != null)
{
ireader.close();
ireader = tr;
}
}
return new IndexSearcher(ireader);
} catch (CorruptIndexException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
return null;
}
public void searchByTerm(String field, String keyword, int num) throws InvalidTokenOffsetsException
{
IndexSearcher isearcher = getSearcher();
Analyzer analyzer = getAnalyzer();
// 使用QueryParser查询分析器构造Query对象
QueryParser qp = new QueryParser(version, field, analyzer);
// 这句所起效果？
qp.setDefaultOperator(QueryParser.OR_OPERATOR);
try
{
Query query = qp.parse(keyword);
ScoreDoc[] hits;
// 注意searcher的几个方法
hits = isearcher.search(query, null, num).scoreDocs;
// 关键字高亮显示的html标签，需要导入lucene-highlighter-xxx.jar
SimpleHTMLFormatter simpleHTMLFormatter = new SimpleHTMLFormatter("<span style='color:red'>", "</span>");
Highlighter highlighter = new Highlighter(simpleHTMLFormatter, new QueryScorer(query));
for (int i = 0; i < hits.length; i++)
{
Document doc = isearcher.doc(hits[i].doc);
// 内容增加高亮显示
TokenStream tokenStream = analyzer.tokenStream("content", new StringReader(doc.get("content")));
String content = highlighter.getBestFragment(tokenStream, doc.get("content"));
System.out.println(content);
}
} catch (IOException e)
{
e.printStackTrace();
} catch (ParseException e)
{
e.printStackTrace();
}
}
/**
* 使用过滤器查询
*
* @param field
* @param keyword
* @param num
* @throws InvalidTokenOffsetsException
*/
public void searchByTermFilter(String field, String keyword, int num) throws InvalidTokenOffsetsException
{
IndexSearcher isearcher = getSearcher();
Analyzer analyzer = getAnalyzer();
// 使用QueryParser查询分析器构造Query对象
QueryParser qp = new QueryParser(version, field, analyzer);
// 这句所起效果？
qp.setDefaultOperator(QueryParser.OR_OPERATOR);
try
{
Query query = qp.parse(keyword);
Query q2 = qp.parse("全文检索");
ScoreDoc[] hits;
QueryWrapperFilter filter = new QueryWrapperFilter(q2);
// 注意searcher的几个方法
hits = isearcher.search(query, filter, num).scoreDocs;
// 关键字高亮显示的html标签，需要导入lucene-highlighter-xxx.jar
SimpleHTMLFormatter simpleHTMLFormatter = new SimpleHTMLFormatter("<span style='color:red'>", "</span>");
Highlighter highlighter = new Highlighter(simpleHTMLFormatter, new QueryScorer(query));
for (int i = 0; i < hits.length; i++)
{
Document doc = isearcher.doc(hits[i].doc);
// 内容增加高亮显示
TokenStream tokenStream = analyzer.tokenStream("content", new StringReader(doc.get("content")));
String content = highlighter.getBestFragment(tokenStream, doc.get("content"));
System.out.println(content);
}
} catch (IOException e)
{
e.printStackTrace();
} catch (ParseException e)
{
e.printStackTrace();
}
}
public static void main(String[] args) throws InvalidTokenOffsetsException
{
System.out.println("start");
LuceneDemo04 ld = new LuceneDemo04();
ld.createIndex();
long start = System.currentTimeMillis();
ld.searchByTerm("content", "人民", 500);
System.out.println("end search use " + (System.currentTimeMillis() - start) + "ms");
}
}
运行结果：
start 加载扩展词典：ext.dic
加载扩展停止词典：stopword.dic
中华<span style='color:red'>人民</span>共和国
中国<span style='color:red'>人民</span>从此站起来了
end search use 129ms