接着全文检索Lucene (1) 。 下面我们来深入的研究一下，如何使用Lucene！
从全文检索Lucene (1)中我们可以看出，Lucene就好比一个双向的工作流，一方面是对索引库的维护，另一方面是对查询过程的支持。同时，这也是Lucene的优雅所在。
Lucene索引库构建分析
Lucene查询过程分析
范例分析
下面我会写一个小的demo，大致的功能就是CRUD。类比JDBC，我们不可避免的要写一些工具类来优化我们的代码，减少重复代码。
Article.java
/**
* @Date 2016年8月1日
*
* @author Administrator
*/
package domain;
/**
* @author 郭瑞彪
*
*/
public class Article {
private Integer id;
private String title;
private String content;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTitle() {
return title;
}
@Override
public String toString() {
return "Article [id=" + id + ", title=" + title + ", content=" + content + "]";
}
public void setTitle(String title) {
this.title = title;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
}
LuceneUtils.java
/**
* @Date 2016年8月1日
*
* @author Administrator
*/
package util;
import java.io.IOException;
import java.nio.file.Paths;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
/**
* @author 郭瑞彪
*
*/
public class LuceneUtils {
private static Directory dir;
public static Directory getDir() {
return dir;
}
public static Analyzer getAnalyzer() {
return analyzer;
}
private static Analyzer analyzer;
/**
* 获得一个用于操作索引库的IndexWriter对象
*
* @return
*/
public static IndexWriter getIndexWriter() {
try {
Directory dir = FSDirectory.open(Paths.get("./indexDir/"));
IndexWriterConfig indexWriterConfig = new IndexWriterConfig(new StandardAnalyzer());
IndexWriter indexWriter = new IndexWriter(dir, indexWriterConfig);
return indexWriter != null ? indexWriter : null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/**
* 获得一个索引库查询对象
*
* @return
*/
public static IndexSearcher getIndexSearcher() {
try {
DirectoryReader directoryReader = DirectoryReader.open(FSDirectory.open(Paths.get("./indexDir/")));
IndexReader indexReader = directoryReader;
IndexSearcher indexSearcher = new IndexSearcher(indexReader);
return indexSearcher != null ? indexSearcher : null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/**
* 释放IndexWriter资源
*
* @param indexWriter
*/
public static void closeIndexWriter(IndexWriter indexWriter) {
try {
if (indexWriter != null) {
indexWriter.close();
indexWriter = null;
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 释放IndexSearcher资源
*
* @param indexSearcher
*/
public static void closeIndexSearcher(IndexSearcher indexSearcher) {
try {
if (indexSearcher != null) {
indexSearcher = null;
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
ArticleDocument.java
/**
* @Date 2016年8月1日
*
* @author Administrator
*/
package util;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import domain.Article;
/**
* @author 郭瑞彪
*
*/
public class ArticleDocumentUtils {
/**
* Article转换成Licene的Document
*
* @param article
* @return
*/
public static Document article2Document(Article article) {
Document doc = new Document();
doc.add(new StringField("id", article.getId().toString(), Store.YES));
doc.add(new TextField("title", article.getTitle(), Store.YES));
doc.add(new TextField("content", article.getContent(), Store.YES));
return doc != null ? doc : null;
}
/**
* 将Document转换回Article
*
* @param document
* @return
*/
public static Article document2Article(Document document) {
Article a = new Article();
a.setId(Integer.parseInt(document.get("id")));
a.setTitle(document.get("title"));
a.setContent(document.get("content"));
return a != null ? a : null;
}
}
ArticleIndexDao.java
/**
* @Date 2016年8月1日
*
* @author Administrator
*/
package dao;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.queryparser.classic.MultiFieldQueryParser;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.util.Version;
import domain.Article;
import domain.Page;
import util.ArticleDocumentUtils;
import util.LuceneUtils;
/**
* @author 郭瑞彪
*
*/
public class ArticleIndexDao {
/**
* 将新的数据保存到索引库
*
* @param article
*/
public void save(Article article) {
IndexWriter indexWriter = null;
try {
// 1. article --> document
Document doc = ArticleDocumentUtils.article2Document(article);
// 2. indexWriter.addDocument(document)
indexWriter = LuceneUtils.getIndexWriter();
indexWriter.addDocument(doc);
// 临时代码
indexWriter.close();
} catch (IOException e) {
throw new RuntimeException("ArticleIndexDao--save方法出错！\n" + e);
} finally {
LuceneUtils.closeIndexWriter(indexWriter);
}
}
/**
* 删除索引
*
* @param id
*/
public void delete(Integer id) {
IndexWriter indexWriter = null;
try {
indexWriter = LuceneUtils.getIndexWriter();
indexWriter.deleteDocuments(new Term("id", id.toString()));
} catch (IOException e) {
throw new RuntimeException("ArticleIndexDao--save方法出错！\n" + e);
} finally {
LuceneUtils.closeIndexWriter(indexWriter);
}
}
/**
* 更新索引 <br>
* 更新操作代价很高，一般采取先删除对应的索引，然后在创建这个索引的方式
*
* @param article
*/
public void update(Article article) {
IndexWriter indexWriter = null;
try {
Term term = new Term("id", article.getId().toString());
indexWriter = LuceneUtils.getIndexWriter();
// Document doc = new Document();
// doc.add(new TextField("title", article.getTitle(), Store.YES));
// doc.add(new TextField("content", article.getContent(),
// Store.YES));
// indexWriter.updateDocument(new Term("title", "content"), doc);
// 优化版本的实现就是：先删除愿索引，然后再创建该索引
indexWriter.deleteDocuments(term);
Document doc = ArticleDocumentUtils.article2Document(article);
indexWriter.addDocument(doc);
} catch (IOException e) {
throw new RuntimeException("ArticleIndexDao--save方法出错！\n" + e);
} finally {
LuceneUtils.closeIndexWriter(indexWriter);
}
}
/**
* 从索引库中查询
*
* @param queryString
* 查询字符串
* @return
*/
public List<Article> search(String queryString) {
try {
// 1.queryString -->>Query
String[] queryFields = new String[] { "title", "content" };
Analyzer analyzer = new StandardAnalyzer();
analyzer.setVersion(Version.LUCENE_6_0_0.LUCENE_6_1_0);
QueryParser queryParser = new MultiFieldQueryParser(queryFields, analyzer);
Query query = queryParser.parse(queryString);
// 2. 查询，得到topDocs
IndexSearcher indexSearcher = LuceneUtils.getIndexSearcher();
TopDocs topDocs = indexSearcher.search(query, 100);
// 3.处理结果并返回
int totalHits = topDocs.totalHits;
ScoreDoc[] scoreDocs = topDocs.scoreDocs;
List<Article> articles = new ArrayList<Article>();
for (int i = 0; i < scoreDocs.length; i++) {
ScoreDoc scoreDoc = scoreDocs[i];
Document doc = indexSearcher.doc(scoreDoc.doc);
Article a = ArticleDocumentUtils.document2Article(doc);
articles.add(a);
}
LuceneUtils.closeIndexSearcher(indexSearcher);
return articles.size() > 0 ? articles : null;
} catch (Exception e) {
throw new RuntimeException("ArticleIndexDao-->> search方法出错！\n" + e);
}
}
}
核心操作
总结
经JUnit测试，代码可以正常的通过。
当然，代码中可以进行优化的地方还有很多，但是作为演示来说还是差强人意的吧。
希望对于Lucene6.1.0版本有困难的小伙伴能从中收获到自己需要的内容。