Lucene using spring.

Datetime:2016-08-23 02:12:15          Topic: Lucene           Share

Today we are showing how to instantiate lucene using spring. We will be using annotations for instating the spring bean. Lets jump directly to the example class to see how it is done

import java.io.File;
import java.io.IOException;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.SearcherManager;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.NIOFSDirectory;
import org.apache.lucene.util.Version;
import org.springframework.stereotype.Component;

/**
 *
 * @author tutorial.author
 *
 */

@Component
public class SpringIndexManager {

 private static Logger logger = LogManager
   .getLogger(SpringIndexManager.class);

 private String indexDirectory = "/opt/myapp/index";
 private FSDirectory directory;

 private IndexWriter writer;

 private SearcherManager searcherManager;

 @PostConstruct
 public void init() {
  try {
   logger.info("index path :" + indexDirectory);
   this.directory = NIOFSDirectory.open(new File(this.indexDirectory));
   this.writer = getIndexWriter(this.indexDirectory);
   this.searcherManager = new SearcherManager(writer, true, null);
  } catch (Exception e) {
   logger.error("error : " + this.indexDirectory, e);
  }
 }

 @PreDestroy
 public void close() {
  logger.info("close writer");
  try {
   this.closeWriter();
   if (this.searcherManager != null) {
    this.searcherManager.close();
   }
   logger.info("SpringIndexManager shutdown done successfully!");
  } catch (CorruptIndexException e) {
   logger.error(e.getMessage(), e);
  } catch (IOException e) {
   logger.error(e.getMessage(), e);
  }
 }

 private IndexWriter getIndexWriter(String path) throws Exception {
  IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_4_9, new StandardAnalyzer(Version.LUCENE_4_9));
  return new IndexWriter(this.directory, config);
 }

 public void closeWriter() throws CorruptIndexException, IOException {
  if (this.writer != null) {
   this.writer.close();
  }
 }

}

So the above class is a singleton spring bean.

The annotation  PostConstruct on the method  init make sure that lucene IndexWriter is started on the startup.

The annotation  PreDestroy makes sure that  close method is called on shutdown.

You can use that class in your application as it is to start and stop lucene. I will soon be writing also about how to write and search text using lucene.





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