hbase上应用lucene创建索引及检索

    hbasene(https://github.com/akkumar/hbasene)是开源项目，在hbase存储上封装使用Lucene来创建索引，代码API非常简单，熟悉lucene的朋友可以很方便地创建。 

    以下为测试代码，完成读取一张hbase上记录url和用户id的表，对其创建索引并进行简单的基于url的索引的代码。当取到search的结果后，就可以拿到想要的数据了。由于分词后将原始内容进行了反向索引，所以匹配就转化为了查询，速度相当快。 

    其中getDocumentFromHTable为读取一张hbase上己有的表，将url字段提取出来创建content索引。 

    创建索引的实质是用了HBaseIndexWriter和HBaseIndexReader两个分别继承自IndexWriter和IndexReader的类来做索引的读取和写入。同时使用了HBaseIndexStore来做存储。 

    而创建索引使用的分词等仍然是使用标准的lucene API。 

    注意hbasene使用的是hbase-0.20.5，需要修改少量源代码才能运行在0.90.x以上的版本中。 

    这里对创建索引表使用到的结构做下简单的说明，因为是lucene入门级水平，所以各位请尽管拍砖讨论。 

    索引表由以下几个CF构成: 

• fm.sequence: 记录sequenceId，在执行createLuceneIndexTable时需要写死该CF的row为sequenceId,qulifier为qual.sequence，值为-1。可以不用理会
• fm.doc2int: DocumentId,每个document都会有一个这样的id,如果Field.Store设置为YES，则能在索引表中查询到该id并得到完整的内容。
• fm.termVector: 向量偏移，用于模糊查找，记录偏移量等信息
• fm.termFrequency:分词后的关键词在每个document中出现的频率，qulifier为documentId，value为出现次数
• fm.fields:记录了content内容，row为documentId，value为document的全文内容，它和fm.docint是相反的，后者是反向索引。
• fm.payloads:扩展CF，目前还没有用到

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.HTablePool;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.Fieldable;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.util.Version;
import org.hbasene.index.HBaseIndexReader;
import org.hbasene.index.HBaseIndexStore;
import org.hbasene.index.HBaseIndexWriter;

public class test{
      static final String indexName = "myindex";
      static final String dataName = "t1";
      public static void main(String[] args) throws IOException {
        
        try{
        Configuration conf = HBaseConfiguration.create(); //hbase-site.xml in the classpath
        conf.set("hbase.rootdir", "hdfs://192.168.0.1:9000/hbase");
        conf.set("hbase.zookeeper.quorum", "192.168.0.1,192.168.0.2,192.168.0.3");
        HTablePool tablePool = new HTablePool(conf, 10);
        HBaseIndexStore.createLuceneIndexTable(indexName, conf, true);
        //Write
        HBaseIndexStore hbaseIndex = new HBaseIndexStore(tablePool, conf, indexName);
        HBaseIndexWriter writer = new HBaseIndexWriter(hbaseIndex, "content"); //Name of the primary key field.

        getDocument(writer);
        writer.close();
        
        //Read/Search
        IndexReader reader = new HBaseIndexReader(tablePool, indexName, "f");
        IndexSearcher searcher = new IndexSearcher(reader);
        Term term = new Term("content", "item.taobao.com");
        TermQuery termQuery = new TermQuery(term);
        TopDocs docs = searcher.search(termQuery, 3);
        searcher.close();
        }catch(IOException e){
            e.printStackTrace();
            throw e;
        }
      }


      private static void getDocument(HBaseIndexWriter writer) throws IOException{
        Document doc = new Document();
        doc.add(new Field("content", "some content some dog", Field.Store.YES,
            Field.Index.ANALYZED));
        writer.addDocument(doc, new StandardAnalyzer(Version.LUCENE_30));
        doc = new Document();
        doc.add(new Field("content", "some id", Field.Store.NO, Field.Index.ANALYZED));
        writer.addDocument(doc, new StandardAnalyzer(Version.LUCENE_30));
        doc = new Document();
        doc.add(new Field("content", "hot dog", Field.Store.YES, Field.Index.ANALYZED, Field.TermVector.WITH_POSITIONS));
        writer.addDocument(doc, new StandardAnalyzer(Version.LUCENE_30));
      }
      
      private static void getDocumentFromHTable(HTablePool tablePool, HBaseIndexWriter writer) throws IOException  {
          Document doc = new Document();
          Scan scan = new Scan();
          HTable htable = (HTable)tablePool.getTable(dataName);
          ResultScanner results = htable.getScanner(scan);
          Result row;
          while((row = results.next()) != null){
              doc = new Document();
              String value = new String(row.getValue("test".getBytes(), null));
              String url = value.split("\"")[2];
              doc.add(new Field("content", url, Field.Store.YES, Field.Index.ANALYZED, Field.TermVector.WITH_OFFSETS));
              writer.addDocument(doc, new StandardAnalyzer(Version.LUCENE_30));
          }
        }
}

 参考：http://koven2049.iteye.com/blog/1129994