04.索引的建立与维护

建立索引

public void createIndex() throws IOException {
   //先指定索引库存放的位置
   String dumpPath = "D:\\temp\\1110";
   Directory directory = FSDirectory.open(new File(dumpPath));
   //索引库存放在内存中
   //Directory directory = new RAMDirectory();
   //指定分析器
   StandardAnalyzer standardAnalyzer = new StandardAnalyzer();
   IndexWriterConfig config = new IndexWriterConfig(Version.LATEST, standardAnalyzer);
   //创建Indexwriter对象
   IndexWriter indexWriter = new IndexWriter(directory, config);
   //读取歌词并创建Document对象
   File musicDir = new File("D:\\传智播客\\01.课程\\04.lucene\\01.参考资料\\歌词\\英文歌词");
   for (File f:musicDir.listFiles()) {
       //判断是否是文件
       if (f.isFile()) {
           //创建Document对象
           Document document = new Document();
          //创建域
          //文件名称
           Field fieldName = new TextField("filename", f.getName(), Store.YES);
          //文件内容
          String contentString = FileUtils.readFileToString(f);
          Field fieldContent = new TextField("content", contentString, Store.YES);
           //文件路径
           Field fieldPath = new StoredField("path", f.getPath());
           //文件 的大小
           Field fieldSize = new LongField("size", FileUtils.sizeOf(f), Store.YES);
          //把域添加到Document中
           document.add(fieldName);
           document.add(fieldContent);
           document.add(fieldPath);
           document.add(fieldSize);
           //把Document写入索引库
           indexWriter.addDocument(document);
       }
   }
   //关闭indexwriter
   indexWriter.close();
}

删除索引

删除所有索引

public void deleteAllIndex() throws IOException {
   IndexWriter indexWriter = getIndexWriter();
   indexWriter.deleteAll();
   indexWriter.commit();
}

删除指定索引

public void deleteIndex() throws IOException {
   IndexWriter indexWriter = getIndexWriter();
   //创建一个查询
   Query query = new TermQuery(new Term("filename", "张信哲"));
   indexWriter.deleteDocuments(query);
   indexWriter.commit();
}

更新索引(会替换文档)

// 索引目录
public void updateIndex( ) throws Exception{
   Directory directory = FSDirectory.open(new File(indexFolder));
   // 定义索引操作对象
   IndexWriter indexWriter = new IndexWriter(directory,
   new IndexWriterConfig(Version.LUCENE_4_10_3,
   new StandardAnalyzer()));
   // 创建更新文档
   Document doc_update = new Document();
   Field field_fileName = new TextField("fileName", "springmvc.txt",
   Store.YES);
   doc_update.add(field_fileName);
   // 根据条件更新索引,将fileName等于“springmvc_test.txt”的更新为上边的文档
   // 更新的机制 是先删除再添加，如果原根据fileName没有找到“springmvc_test.txt”，则添加新文档
   indexWriter.updateDocument(new Term("fileName", "springmvc_test.txt"),
   doc_update);
   //提交
   indexWriter.commit();
   //关闭
   indexWriter.close();
}