hbase 二级索引具体实例

You need to enable indexing in HBase before you can create a secondary index on columns. Edit the file $HBASE_INSTALL_DIR/conf/hbase-site.xml and add the following property to it.

<property><name>hbase.regionserver.class</name><value>org.apache.hadoop.hbase.ipc.IndexedRegionInterface</value></property>      <property>         <name>hbase.regionserver.impl</name>         <value>org.apache.hadoop.hbase.regionserver.tableindexed.IndexedRegionServer</value>     </property>

//Adding secondary index while creating table:HBaseConfiguration conf = new HBaseConfiguration();     conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));      HTableDescriptor desc = new HTableDescriptor("test_table");      desc.addFamily(new HColumnDescriptor("columnfamily1:"));     desc.addFamily(new HColumnDescriptor("columnfamily2:"));      desc.addIndex(new IndexSpecification("column1",Bytes.toBytes("columnfamily1:column1")));     desc.addIndex(new IndexSpecification("column2",Bytes.toBytes("columnfamily1:column2")));IndexedTableAdmin admin = null;     admin = new IndexedTableAdmin(conf);      admin.createTable(desc);  //Adding index in an existing table:      HBaseConfiguration conf = new HBaseConfiguration();     conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));      IndexedTableAdmin admin = null;     admin = new IndexedTableAdmin(conf);      admin.addIndex(Bytes.toBytes("test_table"), new IndexSpecification("column2",Bytes.toBytes("columnfamily1:column2")));  //Deleting existing index from a table.HBaseConfiguration conf = new HBaseConfiguration();     conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));      IndexedTableAdmin admin = null;     admin = new IndexedTableAdmin(conf);      admin.removeIndex(Bytes.toBytes("test_table"), "column2");//Reading from secondary indexed columns://To read from a secondary index, get a scanner for the index and scan through the data.      HBaseConfiguration conf = new HBaseConfiguration();     conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));      IndexedTable table = new IndexedTable(conf, Bytes.toBytes("test_table"));     // You need to specify which columns to get     Scanner scanner = table.getIndexedScanner("column1",HConstants.EMPTY_START_ROW, null, null, new byte[][] {Bytes.toBytes("columnfamily1:column1"),Bytes.toBytes("columnfamily1:column2")});for (RowResult rowResult : scanner) {         String value1 = new String(rowResult.get(Bytes.toBytes("columnfamily1:column1")).getValue());String value2 = new String(rowResult.get(Bytes.toBytes("columnfamily1:column2")).getValue());         System.out.println(value1 + ", " + value2);     }      table.close();  //To get a scanner to a subset of the rows specify a column filter.      ColumnValueFilter filter = new ColumnValueFilter(Bytes.toBytes("columnfamily1:column1"),CompareOp.LESS, Bytes.toBytes("value1-10"));      scanner = table.getIndexedScanner("column1", HConstants.EMPTY_START_ROW,null, filter, new byte[][] { Bytes.toBytes("columnfamily1:column1"),Bytes.toBytes("columnfamily1:column2"));      for (RowResult rowResult : scanner) {         String value1 = new String(             rowResult.get(Bytes.toBytes("columnfamily1:column1")).getValue());         String value2 = new String(rowResult.get(Bytes.toBytes("columnfamily1:column2")).getValue());         System.out.println(value1 + ", " + value2);     }Example Code:import java.io.IOException; import java.util.Date;import org.apache.hadoop.fs.Path; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.HColumnDescriptor; import org.apache.hadoop.hbase.HConstants; import org.apache.hadoop.hbase.HTableDescriptor; import org.apache.hadoop.hbase.client.Scanner; import org.apache.hadoop.hbase.client.tableindexed.IndexSpecification; import org.apache.hadoop.hbase.client.tableindexed.IndexedTable; import org.apache.hadoop.hbase.client.tableindexed.IndexedTableAdmin; import org.apache.hadoop.hbase.filter.ColumnValueFilter; import org.apache.hadoop.hbase.filter.ColumnValueFilter.CompareOp; import org.apache.hadoop.hbase.io.BatchUpdate; import org.apache.hadoop.hbase.io.RowResult; import org.apache.hadoop.hbase.util.Bytespublic class SecondaryIndexTest {     public void writeToTable() throws IOException {         HBaseConfiguration conf = new HBaseConfiguration();         conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));          IndexedTable table = new IndexedTable(conf, Bytes.toBytes("test_table"));          String row = "test_row";         BatchUpdate update = null;          for (int i = 0; i < 100; i++) {             update = new BatchUpdate(row + i);             update.put("columnfamily1:column1", Bytes.toBytes("value1-" + i));             update.put("columnfamily1:column2", Bytes.toBytes("value2-" + i));             table.commit(update);         }          table.close(); }public void readAllRowsFromSecondaryIndex() throws IOException {          HBaseConfiguration conf = new HBaseConfiguration();          conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));           IndexedTable table = new IndexedTable(conf, Bytes.toBytes("test_table"));           Scanner scanner = table.getIndexedScanner("column1",HConstants.EMPTY_START_ROW, null, null, new byte[][] {Bytes.toBytes("columnfamily1:column1"),Bytes.toBytes("columnfamily1:column2") });           for (RowResult rowResult : scanner) {              System.out.println(Bytes.toString(rowResult.get(Bytes.toBytes("columnfamily1:column1")).getValue())+ ", " + Bytes.toString(rowResult.get(Bytes.toBytes("columnfamily1:column2")).getValue()));          }           table.close();     }  public void readFilteredRowsFromSecondaryIndex() throws IOException {          HBaseConfiguration conf = new HBaseConfiguration();          conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));           IndexedTable table = new IndexedTable(conf, Bytes.toBytes("test_table"));           ColumnValueFilter filter = new ColumnValueFilter(Bytes.toBytes("columnfamily1:column1"),CompareOp.LESS, Bytes.toBytes("value1-40")); Scanner scanner = table.getIndexedScanner("column1",HConstants.EMPTY_START_ROW, null, filter,new byte[][] { Bytes.toBytes("columnfamily1:column1"),Bytes.toBytes("columnfamily1:column2")});           for (RowResult rowResult : scanner) {              System.out.println(Bytes.toString(rowResult.get(Bytes.toBytes("columnfamily1:column1")).getValue())+ ", " + Bytes.toString(rowResult.get(Bytes.toBytes("columnfamily1:column2")).getValue())); }           table.close();     }  public void createTableWithSecondaryIndexes() throws IOException {          HBaseConfiguration conf = new HBaseConfiguration();          conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));           HTableDescriptor desc = new HTableDescriptor("test_table");           desc.addFamily(new HColumnDescriptor("columnfamily1:column1"));          desc.addFamily(new HColumnDescriptor("columnfamily1:column2"));           desc.addIndex(new IndexSpecification("column1",Bytes.toBytes("columnfamily1:column1")));          desc.addIndex(new IndexSpecification("column2",Bytes.toBytes("columnfamily1:column2")));           IndexedTableAdmin admin = null;          admin = new IndexedTableAdmin(conf);           if (admin.tableExists(Bytes.toBytes("test_table"))) { if (admin.isTableEnabled("test_table")) {                  admin.disableTable(Bytes.toBytes("test_table"));              }               admin.deleteTable(Bytes.toBytes("test_table"));          }           if (admin.tableExists(Bytes.toBytes("test_table-column1"))) {              if (admin.isTableEnabled("test_table-column1")) {                  admin.disableTable(Bytes.toBytes("test_table-column1"));              }               admin.deleteTable(Bytes.toBytes("test_table-column1"));          }           admin.createTable(desc);     }     public void addSecondaryIndexToExistingTable() throws IOException {         HBaseConfiguration conf = new HBaseConfiguration();         conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));          IndexedTableAdmin admin = null;         admin = new IndexedTableAdmin(conf);          admin.addIndex(Bytes.toBytes("test_table"),new IndexSpecification("column2",Bytes.toBytes("columnfamily1:column2")));     }      public void removeSecondaryIndexToExistingTable() throws IOException {         HBaseConfiguration conf = new HBaseConfiguration();         conf.addResource(new Path("/opt/hbase-0.19.3/conf/hbase-site.xml"));IndexedTableAdmin admin = null;         admin = new IndexedTableAdmin(conf);          admin.removeIndex(Bytes.toBytes("test_table"), "column2");     }     public static void main(String[] args) throws IOException {         SecondaryIndexTest test = new SecondaryIndexTest();         test.createTableWithSecondaryIndexes();         test.writeToTable();         test.addSecondaryIndexToExistingTable();         test.removeSecondaryIndexToExistingTable();         test.readAllRowsFromSecondaryIndex();         test.readFilteredRowsFromSecondaryIndex();          System.out.println("Done!");     }}