批量处理

package step1;import java.util.ArrayList;
import java.util.List;import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.client.coprocessor.Batch;
import org.apache.hadoop.hbase.util.Bytes;public class Task {public Object[] batchOp(String tablename) throws Exception {/********* Begin *********/Configuration conf = HBaseConfiguration.create();Connection conn = ConnectionFactory.createConnection(conf);Table table = conn.getTable(TableName.valueOf(tablename));List<Row> rows = new ArrayList<>();//删除操作Delete delete = new Delete(Bytes.toBytes("row1"));Delete delete2 = new Delete(Bytes.toBytes("row2"));rows.add(delete);rows.add(delete2);//获取操作Get get = new Get(Bytes.toBytes("row3"));Get get2 = new Get(Bytes.toBytes("row10"));rows.add(get);rows.add(get2);//定义结果数组长度Object[] results = new Object[rows.size()];table.batch(rows, results);//这是一个同步的操作，批量操作的结果将会在操作之后放在results中//delete和put操作的结果为NONE 即没有结果return results;/********* End *********/}
}

扫描表中所有的数据

package step2;import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;public class Task {public void scanTable(String tablename) throws Exception {/********* Begin *********/Configuration conf = HBaseConfiguration.create();Connection conn = ConnectionFactory.createConnection(conf);Table table = conn.getTable(TableName.valueOf(tablename));Scan scan = new Scan();ResultScanner scanner = table.getScanner(scan);for(Result result : scanner){for (Cell cell : result.listCells()) {System.out.println(new String(CellUtil.cloneValue(cell),"utf-8"));}} /********* End *********/}
}

在扫描中使用缓存和批量参数

package step3;import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;public class Task {public void scanTable(String tablename) throws Exception {/********* Begin *********/Configuration conf = HBaseConfiguration.create();Connection conn = ConnectionFactory.createConnection(conf);Table table = conn.getTable(TableName.valueOf(tablename));Scan scan = new Scan();scan.setCaching(200);scan.setStartRow(Bytes.toBytes("1"));//设置从row3开始扫描scan.setStopRow(Bytes.toBytes("row199"));ResultScanner scanner = table.getScanner(scan);for (Result result : scanner) {for(Cell cell :result.listCells()) {System.out.println(new String(CellUtil.cloneValue(cell),"utf-8"));}}/********* End *********/}
}