hadoop-hbase-endpoint例子

count下users表里使用google邮箱的用户数

服务端：

先定义个接口，extends CoprocessorProtocol，接口里定义个方法public long gmailCounter(String userId) throws IOException;

再定义个类，extends BaseEndpointCoprocessor，再implements刚才自己定义的接口GmailCounterProtocol，实现gmailCounter方法

在gmailCounter方法里先构造一个scan，然后InternalScanner scanner = ((RegionCoprocessorEnvironment) getEnvironment()).getRegion().getScanner(scan);

这个InternalScanner需要do-while循环取值，比较怪异

客户端：

先构造：Batch.Call<GmailCounterProtocol, Long> callable

然后EXEC：Map<byte[], Long> rs = table.coprocessorExec(GmailCounterProtocol.class, startKey, endKey, callable);，必须指定startKey和endKey范围

最后循环取结果：for (Map.Entry<byte[], Long> e : rs.entrySet())  { e.getValue().longValue(); }

接口

package test.hbase.inaction.example5_3;import java.io.IOException;import org.apache.hadoop.hbase.ipc.CoprocessorProtocol;public interface GmailCounterProtocol extends CoprocessorProtocol {public long gmailCounter(String userId) throws IOException;}

服务端

package test.hbase.inaction.example5_3;import java.io.IOException;import java.util.ArrayList;import java.util.List;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;import org.apache.hadoop.hbase.KeyValue;import org.apache.hadoop.hbase.client.Scan;import org.apache.hadoop.hbase.coprocessor.BaseEndpointCoprocessor;import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;import org.apache.hadoop.hbase.filter.PrefixFilter;import org.apache.hadoop.hbase.regionserver.InternalScanner;import org.apache.hadoop.hbase.util.Bytes;import test.hbase.inaction.example2_4.UsersDAO;public class UserEndpointServer extends BaseEndpointCoprocessor implementsGmailCounterProtocol {private final Log log = LogFactory.getLog(this.getClass());@Overridepublic long gmailCounter(String prefix) throws IOException {log.info("================================== begin");Scan scan = new Scan(prefix.getBytes());scan.setFilter(new PrefixFilter(prefix.getBytes()));scan.addColumn(UsersDAO.INFO_FAM, UsersDAO.EMAIL_COL);scan.setMaxVersions(1);RegionCoprocessorEnvironment env = (RegionCoprocessorEnvironment) getEnvironment();InternalScanner scanner = env.getRegion().getScanner(scan);long sum = 0;List<KeyValue> kvList = new ArrayList<KeyValue>();boolean hasMore = false;do {hasMore = scanner.next(kvList);for (KeyValue kv : kvList) {log.info(Bytes.toString(kv.getRow()) + ":"+ Bytes.toString(kv.getFamily()) + ":"+ Bytes.toString(kv.getQualifier()) + "="+ Bytes.toString(kv.getValue()));String email = Bytes.toString(kv.getValue());if (email != null && email.toLowerCase().endsWith("@gmail.com")) {sum++;}log.info("sum=" + sum);}kvList.clear();} while (hasMore);scanner.close();log.info("================================== end");return sum;}}

客户端调用

package test.hbase.inaction.example5_3;import java.io.IOException;import java.util.Arrays;import java.util.Map;import org.apache.hadoop.hbase.client.HTableInterface;import org.apache.hadoop.hbase.client.HTablePool;import org.apache.hadoop.hbase.client.coprocessor.Batch;import org.apache.hadoop.hbase.util.Bytes;import test.hbase.inaction.example2_4.UsersDAO;public class UserEndpointClient {private static HTablePool pool = new HTablePool();private static HTableInterface table = pool.getTable(UsersDAO.TABLE_NAME);/** * @param args * @throws Throwable * @throws IOException */public static void main(String[] args) throws Throwable {final String userId = "id";Batch.Call<GmailCounterProtocol, Long> callable = new Batch.Call<GmailCounterProtocol, Long>() {@Overridepublic Long call(GmailCounterProtocol instance) throws IOException {return instance.gmailCounter(userId);}};byte[] startKey = Bytes.toBytes(userId);byte[] endKey = Arrays.copyOf(startKey, startKey.length);endKey[endKey.length - 1]++;Map<byte[], Long> rs = table.coprocessorExec(GmailCounterProtocol.class, startKey, endKey, callable);long sum = 0;for (Map.Entry<byte[], Long> e : rs.entrySet()) {sum += e.getValue().longValue();}System.out.println(sum);}}

hbase-env.sh

export HBASE_CLASSPATH=/home/u/myjar/FollowsObserver.jar

hbase-site.xml

<configuration>
<property>
    <name>hbase.rootdir</name>
    <value>hdfs://172.10.10.144:9000/hbase</value>
</property>
<property>
    <name>dfs.replication</name>
    <value>1</value>
</property>
<property>
  <name>hbase.coprocessor.region.classes</name>
  <value>test.hbase.inaction.example5_3.UserEndpointServer</value>
</property>
</configuration>

HBase数据库log日志

2014-10-31 16:47:45,028 INFO test.hbase.inaction.example5_3.UserEndpointServer: id01:info:email=[e-mail]
2014-10-31 16:47:45,028 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=1
2014-10-31 16:47:45,028 INFO test.hbase.inaction.example5_3.UserEndpointServer: id02:info:email=[e-mail]
2014-10-31 16:47:45,028 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=1
2014-10-31 16:47:45,029 INFO test.hbase.inaction.example5_3.UserEndpointServer: id03:info:email=[e-mail]
2014-10-31 16:47:45,029 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=2
2014-10-31 16:47:45,029 INFO test.hbase.inaction.example5_3.UserEndpointServer: id04:info:email=[e-mail]
2014-10-31 16:47:45,029 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=2
2014-10-31 16:47:45,030 INFO test.hbase.inaction.example5_3.UserEndpointServer: id05:info:email=[e-mail]
2014-10-31 16:47:45,030 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=2
2014-10-31 16:47:45,030 INFO test.hbase.inaction.example5_3.UserEndpointServer: id06:info:email=[e-mail]
2014-10-31 16:47:45,030 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=3
2014-10-31 16:47:45,030 INFO test.hbase.inaction.example5_3.UserEndpointServer: id07:info:email=[e-mail]
2014-10-31 16:47:45,030 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=4
2014-10-31 16:47:45,031 INFO test.hbase.inaction.example5_3.UserEndpointServer: id08:info:email=[e-mail]
2014-10-31 16:47:45,031 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=5
2014-10-31 16:47:45,031 INFO test.hbase.inaction.example5_3.UserEndpointServer: id09:info:email=[e-mail]
2014-10-31 16:47:45,031 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=5
2014-10-31 16:47:45,032 INFO test.hbase.inaction.example5_3.UserEndpointServer: id99:info:email=[e-mail]
2014-10-31 16:47:45,032 INFO test.hbase.inaction.example5_3.UserEndpointServer: sum=6