分词的基本原理:
1、分词是用来对文本按语言特征按算法进行过滤、分组处理的一种技术。
2、分词的对象是文本,而不是图像动画脚本等等。
3、分词的方式就是过滤和分组。
4、过滤主要把文本中那些没有实际意义的字或词过滤掉。
5、分组就是按照”分词数据库“内已添加好的词,进行匹配。
下面来看Lucene分词器的使用
- package com.qianyan.analyzer;
- import java.io.IOException;
- import java.io.StringReader;
- import org.apache.lucene.analysis.Analyzer;
- import org.apache.lucene.analysis.SimpleAnalyzer;
- import org.apache.lucene.analysis.Token;
- import org.apache.lucene.analysis.TokenStream;
- import org.apache.lucene.analysis.WhitespaceAnalyzer;
- import org.apache.lucene.analysis.cjk.CJKAnalyzer;
- import org.apache.lucene.analysis.cn.ChineseAnalyzer;
- import org.apache.lucene.analysis.standard.StandardAnalyzer;
- public class TestAnalyzer {
- public static void main(String[] args) throws IOException {
- Analyzer analyzer = new StandardAnalyzer(); //标准 过滤停用次
- //Analyzer analyzer = new SimpleAnalyzer(); //简单 过滤空格和符号
- //Analyzer analyzer = new WhitespaceAnalyzer(); //过滤空格
- //Analyzer analyzer = new ChineseAnalyzer(); //lucene下的中文分词器 拆分每个字符,过滤符号
- //Analyzer analyzer = new CJKAnalyzer(); //中文 两字两字拆分 英文和standard功能一样
- String input = "this is test lucene analyzer class!";
- TokenStream tokenStream = analyzer.tokenStream("", new StringReader(input));
- Token token = new Token();
- while(null != tokenStream.next(token))
- System.out.println(token.term());
- }
- }
对于初学者,我们只需要掌握这些经典的分词器就足够了。
但在实际的开发过程中,满足我们需要得,是一些基于lucene分词之上的第三方中文分词包,在这里我们只介绍 ”庖丁分词包“,命令借鉴了”庖丁解牛“这个成语。
庖丁解牛,我国古代成语,出自《庄子》,比喻经过反复实践,掌握了事物的客观规律,做事得心应手,运用自如。
下载网址链接:http://code.google.com/p/paoding/
解压后我们需要对项目添加2个jar包,解压目录下的paoding-analysis.jar 和lib下的 commons-logging.jar 。令把dic文件夹复制到我们的项目src目录下。
- package com.qianyan.analyzer;
- import java.io.IOException;
- import java.io.StringReader;
- import net.paoding.analysis.analyzer.PaodingAnalyzer;
- import org.apache.lucene.analysis.Analyzer;
- import org.apache.lucene.analysis.Token;
- import org.apache.lucene.analysis.TokenStream;
- public class TestPaodingAnalyzer {
- public static void main(String[] args) throws IOException {
- Analyzer analyzer = new PaodingAnalyzer();
- String input = "我爱北京天安门!";
- TokenStream ts = analyzer.tokenStream("", new StringReader(input));
- Token token = new Token();
- while(null != (token = ts.next(null)))
- System.out.println(token.term());
- }
- }
大家通过这个例子可以看到,paoding分词器相当的强大,它的语法在此不过多介绍,有兴趣的朋友可以看解压后的中文操作手册。
下面来看下实际中运用
首先根据paoding分词器建立索引:
- package com.qianyan.index;
- import java.io.IOException;
- import net.paoding.analysis.analyzer.PaodingAnalyzer;
- import org.apache.lucene.analysis.Analyzer;
- import org.apache.lucene.document.Document;
- import org.apache.lucene.document.Field;
- import org.apache.lucene.index.IndexWriter;
- import org.apache.lucene.store.Directory;
- import org.apache.lucene.store.FSDirectory;
- public class TestPaodingIndex {
- public static void main(String[] args) throws IOException{
- String[] ids = {"1", "2", "3", "4"};
- String[] names = {"张三", "李四", "李五", "赵六"};
- String[] addresses = {"居住在北京", "南京", "北京海淀", "南宁"};
- String[] birthdays = {"19820720", "19840203", "19770409", "19830130"};
- Analyzer analyzer = new PaodingAnalyzer();
- String indexDir = "E:/luceneindex";
- Directory dir = FSDirectory.getDirectory(indexDir);
- IndexWriter writer = new IndexWriter(dir, analyzer, true, IndexWriter.MaxFieldLength.UNLIMITED);
- for(int i = 0; i < ids.length; i++){
- Document document = new Document();
- document.add(new Field("id", ids[i], Field.Store.YES, Field.Index.ANALYZED));
- document.add(new Field("name", names[i], Field.Store.YES, Field.Index.ANALYZED));
- document.add(new Field("address", addresses[i], Field.Store.YES, Field.Index.ANALYZED));
- document.add(new Field("birthday", birthdays[i], Field.Store.YES, Field.Index.ANALYZED));
- writer.addDocument(document);
- }
- writer.optimize();
- writer.close();
- }
- }
然后来看简单的检索类
- package com.qianyan.search;
- import java.io.IOException;
- import org.apache.lucene.document.Document;
- import org.apache.lucene.index.Term;
- import org.apache.lucene.search.IndexSearcher;
- import org.apache.lucene.search.PrefixQuery;
- import org.apache.lucene.search.ScoreDoc;
- import org.apache.lucene.search.TermQuery;
- import org.apache.lucene.search.TopDocs;
- import org.apache.lucene.search.WildcardQuery;
- import org.apache.lucene.store.Directory;
- import org.apache.lucene.store.FSDirectory;
- public class TestPaodingSearch {
- public static void main(String[] args) throws IOException {
- String indexDir = "E:/luceneindex";
- Directory dir = FSDirectory.getDirectory(indexDir);
- IndexSearcher searcher = new IndexSearcher(dir);
- ScoreDoc[] hits = null;
- /*Term term = new Term("address", "北京");
- TermQuery query = new TermQuery(term);
- */
- /*Term term = new Term("name", "张");
- PrefixQuery query = new PrefixQuery(term);*/
- Term term = new Term("name", "李*");
- WildcardQuery query = new WildcardQuery(term);
- TopDocs topDocs = searcher.search(query, 100);
- hits = topDocs.scoreDocs;
- for(int i = 0; i < hits.length; i++){
- Document doc = searcher.doc(hits[i].doc);
- System.out.print(hits[i].score + " ");
- System.out.print(doc.get("id") + " ");
- System.out.print(doc.get("name") + " ");
- System.out.print(doc.get("address") + " ");
- System.out.println(doc.get("birthday") + " ");
- }
- searcher.close();
- dir.close();
- }
- }
下面是来看QueryParser检索类
- package com.qianyan.search;
- import java.io.IOException;
- import net.paoding.analysis.analyzer.PaodingAnalyzer;
- import org.apache.lucene.analysis.Analyzer;
- import org.apache.lucene.document.Document;
- import org.apache.lucene.queryParser.ParseException;
- import org.apache.lucene.queryParser.QueryParser;
- import org.apache.lucene.search.IndexSearcher;
- import org.apache.lucene.search.Query;
- import org.apache.lucene.search.ScoreDoc;
- import org.apache.lucene.search.TopDocCollector;
- import org.apache.lucene.store.Directory;
- import org.apache.lucene.store.FSDirectory;
- public class TestQueryParser {
- public static void main(String[] args) throws IOException, ParseException {
- Analyzer analyzer = new PaodingAnalyzer();
- String indexDir = "E:/luceneindex";
- Directory dir = FSDirectory.getDirectory(indexDir);
- IndexSearcher searcher = new IndexSearcher(dir);
- ScoreDoc[] hits = null;
- QueryParser parser = new QueryParser("address", analyzer); //name为默认字段检索
- Query query = parser.parse("北京");
- //Query query = parser.parse("birthday:[19820720 TO 19840203]"); //中括号包含首尾,花括号不包含。TO指范围
- //Query query = parser.parse("张~"); //前缀检索
- //Query query = parser.parse("上海 北京");
- //Query query = parser.parse("(居住 or 北京) and 海淀");
- //Query query = parser.parse("上海 北京 AND NOT name:李四");
- //Query query = parser.parse("name:李*"); //前缀检索
- TopDocCollector topdoc = new TopDocCollector(100);
- searcher.search(query, topdoc);
- hits = topdoc.topDocs().scoreDocs;
- for(int i = 0; i < hits.length; i++){
- Document doc = searcher.doc(hits[i].doc);
- //System.out.println(hits[i].score);
- System.out.print(doc.get("id") + " ");
- System.out.print(doc.get("name") + " ");
- System.out.print(doc.get("address") + " ");
- System.out.println(doc.get("birthday") + " ");
- }
- searcher.close();
- dir.close();
- }
- }
下面我们来学习Paoding对文件的索引
- package com.qianyan.file;
- import java.io.BufferedReader;
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.IOException;
- import java.io.InputStreamReader;
- import net.paoding.analysis.analyzer.PaodingAnalyzer;
- import org.apache.lucene.analysis.Analyzer;
- import org.apache.lucene.document.Document;
- import org.apache.lucene.document.Field;
- import org.apache.lucene.index.IndexWriter;
- import org.apache.lucene.store.Directory;
- import org.apache.lucene.store.FSDirectory;
- public class TestFileIndex {
- public static void main(String[] args) throws IOException {
- String dataDir = "E:\\lucenedata";
- String indexDir = "E:\\luceneindex";
- File[] files = new File(dataDir).listFiles();
- Analyzer analyzer = new PaodingAnalyzer();
- Directory dir = FSDirectory.getDirectory(indexDir);
- IndexWriter writer = new IndexWriter(dir, analyzer, true, IndexWriter.MaxFieldLength.UNLIMITED);
- for(int i = 0; i < files.length; i++){
- StringBuffer strBuffer = new StringBuffer();
- String line = "";
- FileInputStream fs = new FileInputStream(files[i].getCanonicalPath());
- BufferedReader reader = new BufferedReader(new InputStreamReader(fs));
- line = reader.readLine();
- while(null != line){
- strBuffer.append(line).append("\n");
- line = reader.readLine();
- }
- Document document = new Document();
- document.add(new Field("fileName", files[i].getName(), Field.Store.YES, Field.Index.ANALYZED));
- document.add(new Field("contents", strBuffer.toString(), Field.Store.YES, Field.Index.ANALYZED));
- writer.addDocument(document);
- fs.close();
- reader.close();
- }
- writer.close();
- dir.close();
- }
- }
然后是对之前索引的检索类:
- package com.qianyan.file;
- import java.io.IOException;
- import org.apache.lucene.document.Document;
- import org.apache.lucene.index.Term;
- import org.apache.lucene.search.IndexSearcher;
- import org.apache.lucene.search.ScoreDoc;
- import org.apache.lucene.search.TermQuery;
- import org.apache.lucene.search.TopDocs;
- import org.apache.lucene.search.WildcardQuery;
- import org.apache.lucene.store.Directory;
- import org.apache.lucene.store.FSDirectory;
- public class TestSearch {
- public static void main(String[] args) throws IOException {
- String indexDir = "E:/luceneindex";
- Directory dir = FSDirectory.getDirectory(indexDir);
- IndexSearcher searcher = new IndexSearcher(dir);
- ScoreDoc[] hits = null;
- Term term = new Term("fileName", "星期");
- TermQuery query = new TermQuery(term);
- TopDocs topDocs = searcher.search(query, 100);
- hits = topDocs.scoreDocs;
- for(int i = 0; i < hits.length; i++){
- Document doc = searcher.doc(hits[i].doc);
- System.out.print(hits[i].score + " ");
- System.out.println(doc.get("fileName") + " ");
- System.out.println(doc.get("contents") + " ");
- }
- searcher.close();
- dir.close();
- }
- }