Lucene 对索引库的增删改查操作的 API 演示
没什么说的，apache 的 API 一向简单、不难理解。所以直接拷代码过去稍微看一下就差不多了。
/**
* "文章" 实体
*/
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;
}
public void setTitle(String title) {
this.title = title;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
}
/**
* 描述某一页的检索结果集
*/
public class QueryResult {
/* 匹配的总记录数 */
private int totalCount;
/* 检索到的文章对象集合 */
private List<Article> atrticle;
public QueryResult(int totalCount, List<Article> atrticle) {
this.totalCount = totalCount;
this.atrticle = atrticle;
}
public int getTotalCount() {
return totalCount;
}
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
}
public List<Article> getAtrticle() {
return atrticle;
}
public void setAtrticle(List<Article> atrticle) {
this.atrticle = atrticle;
}
}
/**
* 直接操作索引库的 DAO
*/
public class ArticleIndexDao {
/**
* 保存索引
* @param article
*/
public void save(Article article) {
Document document = Article2DocumentUtil.article2document(article);
IndexWriter indexWriter = null;
try {
Directory indexDir = FSDirectory.open(new File("./indexDir/"));
// 标准分词器，另外 Lucene 还提供了针对多种语言的分词器
Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_30);
indexWriter = new IndexWriter(indexDir, analyzer,
MaxFieldLength.LIMITED);
indexWriter.addDocument(document);
} catch (IOException e) {
throw new RuntimeException(e);
} finally {
if (indexWriter != null) {
try {
indexWriter.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
}
/**
* 删除
*
* @param article
* 删除的 Article 对象
*/
public void delete(Article article) {
IndexWriter indexWriter = null;
try {
Directory indexDir = FSDirectory.open(new File("./indexDir/"));
Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_30);
indexWriter = new IndexWriter(indexDir, analyzer,
MaxFieldLength.LIMITED);
/* 意思是将索引库中 id 为 article.getId() 的记录删了 */
Term term = new Term("id", article.getId() + "");
indexWriter.deleteDocuments(term);
} catch (IOException e) {
throw new RuntimeException(e);
} finally {
if (indexWriter != null) {
try {
indexWriter.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
}
/**
* 修改
*/
public void update(Article article) {
IndexWriter indexWriter = null;
try {
Directory indexDir = FSDirectory.open(new File("./indexDir/"));
Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_30);
indexWriter = new IndexWriter(indexDir, analyzer,
MaxFieldLength.LIMITED);
/* 意思是将索引库中 id 为 article.getId() 的记录改了 */
Term term = new Term("id", article.getId() + "");
indexWriter.updateDocument(term, Article2DocumentUtil
.article2document(article));
/*
* updateDocument 等价于： delete(article); save(article);
* 在大数据量的时候，采用 "删除再创建" 的效率更高
*/
} catch (IOException e) {
throw new RuntimeException(e);
} finally {
if (indexWriter != null) {
try {
indexWriter.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
}
/**
* 分页搜索
* @param queryStr 搜索条件
* @param firstResult 首条数据位置
* @param maxResults 最多取多少条数据
* @return 一页结果集
*/
public QueryResult search(String queryStr, int firstResult, int maxResults) {
IndexSearcher indexSearcher = null;
List<Article> atrticles = new ArrayList<Article>();
try {
/*
* 构建 IndexSearcher
*/
Directory indexDir = FSDirectory.open(new File("./indexDir/"));
indexSearcher = new IndexSearcher(indexDir);
/*
* 构建 Query
*/
Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_30);
QueryParser queryParser = new QueryParser(Version.LUCENE_30, "content", analyzer);
Query query = queryParser.parse(queryStr);
/*
* 查询
*/
TopDocs topDocs = indexSearcher.search(query, firstResult + maxResults);
int totalCount = topDocs.totalHits;
ScoreDoc[] scoreDocs = topDocs.scoreDocs;
/* 保证循环的次数不超过 scoreDocs 的长度*/
int length = Math.min(firstResult+maxResults, scoreDocs.length);
for(int i=firstResult; i<length; i++) {
/*
* 根据编号取出Document数据
*/
Document document = indexSearcher.doc(i);
Article article = Article2DocumentUtil.document2article(document);
atrticles.add(article);
}
return new QueryResult(totalCount, atrticles);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
try {
if (indexSearcher != null) {
indexSearcher.close();
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
}
**
* 工具类：Article 对象与 Document 对象的转换
*/
public class Article2DocumentUtil {
public static Document article2document(Article article) {
if(article == null) {
return null;
}
Document document = new Document();
document.add(new Field("id", article.getId()+"", Store.YES, Index.ANALYZED));
document.add(new Field("title", article.getTitle(), Store.YES, Index.ANALYZED));
document.add(new Field("content", article.getContent(), Store.YES, Index.ANALYZED));
return document;
}
public static Article document2article(Document document) {
if(document == null) {
return null;
}
Article article = new Article();
article.setId(Integer.parseInt(document.get("id")));
article.setTitle(document.get("title"));
article.setContent(document.get("content"));
return article;
}
}
/**
* JUnit 测试
*/
public class TestArticleIndexDao {
/**
* 测试保存
* @throws Exception
*/
@Test
public void testSave() throws Exception {
ArticleIndexDao dao = new ArticleIndexDao();
Article article = new Article();
article.setId(1);
article.setTitle("wjh上天山");
article.setContent("据悉，文建华已于昨日抵达天山。高歌一曲HelloWorld");
dao.save(article);
}
@Test
public void testBatchSave() throws Exception {
for(int i=0; i<35; i++) {
ArticleIndexDao dao = new ArticleIndexDao();
Article article = new Article();
article.setId(i);
article.setTitle("wjh上天山第" + i + "集");
article.setContent("据悉，wjh已于昨日抵达天山。高歌"+ i +"曲 HelloWorld");
dao.save(article);
}
}
@Test
public void testUpdate() throws Exception {
ArticleIndexDao dao = new ArticleIndexDao();
Article article = new Article();
article.setId(1);
article.setTitle("wjh上天山");
article.setContent("wjh已于昨日抵达天山。高歌一曲HelloWorld");
dao.update(article);
}
@Test
public void testDel() throws Exception {
ArticleIndexDao dao = new ArticleIndexDao();
Article article = new Article();
article.setId(1);
article.setTitle("wjh上天山");
article.setContent("wjh已于昨日抵达天山。高歌一曲HelloWorld");
dao.delete(article);
}
@Test
public void testSearch() throws Exception {
ArticleIndexDao dao = new ArticleIndexDao();
QueryResult queryResult = dao.search("HelloWorld", 30, 10);
int count = queryResult.getTotalCount();
System.out.println("共匹配了 " + count + " 条记录。");
List<Article> articles = queryResult.getAtrticle();
for (Article article : articles) {
System.out.println("id:" + article.getId());
System.out.println("title:" + article.getTitle());
System.out.println("content:" + article.getContent());
System.out.println("----------------");
}
}
}