Lucene参与项目持久层中对于索引库的增删改查

本文主要介绍的是Lucene在参与项目中持久层的时候对于索引库增删改查的详细使用；（为了更好地使用Lucene，本文中使用的版本是Lucene4.04，使用的分词器是IKAnalyzer2012FF）

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1、Lucene实现增删改查准备工作
2、Lucene持久层详细实现

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1、Lucene实现增删改查准备工作

• 第一步：创建Java工程，也可以创建pom.xml工程，需要五个jar包：
  common-io.jar
  IKAnalyzer2012FF_u1.jar
  lucene-analyzers-common-4.4.0.jar
  lucene-core-4.4.0.jar
  lucene-queryparser-4.4.0.jar
• 第二步：我们需要一个JavaBean对象用于存储网上新闻或者文章；网上的新闻或者文章主要是有文章题目；文章作者；文章目录；文章链接四个方面组成所以，所以创建Article文章Bean类如下：

Article.java

/**
 * JAVABEAN用于方便存储抓取的文章索引库中的单个对象
 */
public class Article {

private int id;

private String title; 

private String author;

private String content;

private String link;

public int getId() {
return id;
    }
public void setId(int id) {
this.id = id;
    }

public String getTitle() {
return title;
    }
public void setTitle(String title) {
this.title = title;
    }

public String getAuthor() {
return author;
    }
public void setAuthor(String author) {
this.author = author;
    }

public String getContent() {
return content;
    }
public void setContent(String content) {
this.content = content;
    }

public String getLink() {
return link;
    }
public void setLink(String link) {
this.link = link;
    }

@Override
public String toString() {
return "Article [id=" + id + ", title=" + title + ", author=" + author
                + ", content=" + content + ", link=" + link + "]";
    }
}

• 第三步：创建Lucene工具类（用于准备Lucene中最重要的indexWriter和indexReader两个对象）：

LuceneUtils.java

public class LuceneUtils {

private static Directory directory;

private static IndexWriterConfig indexWriterConfig;

private static Version matchVersion = Version.LUCENE_44;

private static Analyzer analyzer = new IKAnalyzer();

static {

try {

            directory = FSDirectory.open(new File(Contants.INDEXURL));

            indexWriterConfig = new IndexWriterConfig(matchVersion, analyzer);

        } catch (IOException e) {
            e.printStackTrace();
        }

    }

/**
 * 获取返回用于操作索引的对象
 * @return
 * @throws IOException
 */
public static IndexWriter getIndexWriter() throws IOException {

        IndexWriter indexWriter = new IndexWriter(directory, indexWriterConfig);

return indexWriter;
    }

/**
 * 获取用于查询索引库的对象
 * @return
 * @throws Exception
 */
public static IndexSearcher getIndexSearcher() throws Exception {

        IndexReader indexReader = DirectoryReader.open(directory);

        IndexSearcher indexSearcher = new IndexSearcher(indexReader);

return indexSearcher;
    }

// 获取索引库地址
public static Directory getDirectory() {
return directory;
    }

// 获取当前的版本
public static Version getMatchVersion() {
return matchVersion;
    }

// 获取分词分析器
public static Analyzer getAnalyzer() {
return analyzer;
    }

}

Contants.java

public interface Contants {
// 存储地址
public static final String INDEXURL = "index/news";

}

• 第四步：创建Article向Document转化的工具类：

ArticleUtils.java

import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field.Store;
import org.apache.lucene.document.IntField;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;

import com.lucene.bean.Article;

/**
 * article 的转化类
 */
public class ArticleUtils {

/**
 * 将article转化为document
 * @param article
 * @return
 */
public static Document articleDocument(Article article) {

        Document document = new Document();

        IntField IDField = new IntField("id", article.getId(), Store.YES);

        StringField titleField = new StringField("title", article.getTitle(), Store.YES);

        TextField contentField = new TextField("content", article.getContent(), Store.YES);

        StringField authorField= new StringField("author", article.getAuthor(), Store.YES);

        StringField urlField   = new StringField("link", article.getLink(), Store.YES);

        document.add(IDField);
        document.add(titleField);
        document.add(contentField);
        document.add(authorField);
        document.add(urlField);

return document;
    }

}

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2、Lucene持久层详细实现

LuceneDao.java

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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.junit.Test;

import com.lucene.bean.Article;
import com.lucene.utils.ArticleUtils;
import com.lucene.utils.LuceneUtils;

/**
 * Lucene操作索引库（Dao层操作）
 */
public class LuceneDao {
/**
 * 增删改索引都通过indexWriter完成
 * @throws IOException 
 */
/**
 * 添加索引库
 * @param article
 * @throws IOException
 */
@Test
public void addIndex(Article article) throws IOException {

        IndexWriter indexWriter = LuceneUtils.getIndexWriter();

        Document document = ArticleUtils.articleDocument(article);

        indexWriter.addDocument(document);

        indexWriter.close();
    }

/**
 * 根据字段删除索引，删除对应的值
 * @param fieldName
 * @param fieldValue
 * @throws Exception
 */
public void delIndex(String fieldName, String fieldValue) throws Exception {
        IndexWriter indexWriter = LuceneUtils.getIndexWriter();

        Term term = new Term(fieldName, fieldValue);

        indexWriter.deleteDocuments(term);
        indexWriter.commit();
        indexWriter.close();
    }

/**
 * 更新索引库中的内容
 * @param fieldName
 * @param fieldValue
 * @param article
 * @throws IOException
 */
public void updateIndex(String fieldName, String fieldValue,Article article) throws IOException {
        IndexWriter indexWriter = LuceneUtils.getIndexWriter();

        Term term = new Term(fieldName, fieldValue);

        Document document = ArticleUtils.articleDocument(article);

        indexWriter.updateDocument(term, document);

        indexWriter.commit();

        indexWriter.close();
    }

/**
 * 
 * 分页数据
 * 
 * 显示数据进行分页 0 , 10
 * 
 * 显示数据进行分页11 , 20 
 * 
 * 在索引库中根据关键字查找
 * @param keywords
 * @return
 * @throws Exception
 */
public List<Article> findIndex(String keywords, int start, int row) throws Exception {

        IndexSearcher indexSearcher = LuceneUtils.getIndexSearcher();

// 需要根据那几个字段进行检索
        String fields[] = {"title","content"};
// String fields[] = {"author"};

        QueryParser queryParser = new MultiFieldQueryParser(LuceneUtils.getMatchVersion(), fields, LuceneUtils.getAnalyzer());

// 不同的规则构造不同的子类
// title：keywords ， content：keywords
        Query query = queryParser.parse(keywords);

        TopDocs topDocs = indexSearcher.search(query, start+row);

        System.out.println("总记录数====total===="+topDocs.totalHits);

        ScoreDoc scoreDocs[] = topDocs.scoreDocs;

        Article article = null;

        List<Article> articlelist = new ArrayList<Article>();

int endResult = Math.min(scoreDocs.length, start+row);

for (int i = start; i < endResult; i++) {
int docID = scoreDocs[i].doc;
            article = new Article();
            Document document = indexSearcher.doc(docID);
            article.setId(Integer.parseInt(document.get("id")));
            article.setTitle(document.get("title"));
            article.setContent(document.get("content"));
            article.setLink(document.get("link"));
            article.setAuthor(document.get("author"));

            articlelist.add(article);
        }

return articlelist;

    }

}