Get stuck when using java api to connect Hbase

问题:

My local environment:

OS X 10.9.2, Hbase-0.94.17, Java 1.6

My Hbase mode: standalone

I was able to do operation in shell, but when I used java api, it did not work.

My java code:

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.util.Bytes;


public class MyLittleHBaseClient {
  public static void main(String[] args) throws IOException {

    Configuration config = HBaseConfiguration.create();
    config.addResource("/Users/apple/Documents/tools/hbase-0.94.17/conf/hbase-site.xml");

    HTable table = new HTable(config, "myLittleHBaseTable");

    Put p = new Put(Bytes.toBytes("myLittleRow"));

    p.add(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"),
      Bytes.toBytes("Some Value"));

    table.put(p);

    Get g = new Get(Bytes.toBytes("myLittleRow"));
    Result r = table.get(g);
    byte [] value = r.getValue(Bytes.toBytes("myLittleFamily"),
      Bytes.toBytes("someQualifier"));

    String valueStr = Bytes.toString(value);
    System.out.println("GET: " + valueStr);

    Scan s = new Scan();
    s.addColumn(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"));
    ResultScanner scanner = table.getScanner(s);
    try {

      for (Result rr = scanner.next(); rr != null; rr = scanner.next()) {
        // print out the row we found and the columns we were looking for
        System.out.println("Found row: " + rr);
      }

    } finally {

      scanner.close();
    }
  }
}

Here is some of my conf doc:

###########################################hbase-env.sh:

export JAVA_HOME=`/usr/libexec/java_home -v '1.6*'`
export HBASE_OPTS="-XX:+UseConcMarkSweepGC"

###########################################hbase-site.sh:

<configuration>
  <property>
    <name>hbase.rootdir</name>
    <value>file:///Users/apple/Documents/tools/hbase-0.94.17/hbase-rootdir/hbase</value>
  </property>
  <property>
    <name>hbase.zookeeper.property.dataDir</name>
    <value>/Users/apple/Documents/tools/hbase-0.94.17/hbase-zookeeper/zookeeper</value>
  </property>
</configuration>

When I ran the java code above, I got the following information:

log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
2014-03-31 13:20:15.037 java[873:1003] Unable to load realm info from SCDynamicStore

and then the console just stopped here and gave nothing more.(no more response)

Also I attach my /Users/apple/Documents/tools/hbase-0.94.17/logs/hbase-apple...local.log here:

https://docs.google.com/file/d/0BxtBre5A8J61Y2k3SXNtNGs1WXM/edit

Thanks for your patient, your answer will be a great help to me :)

回答1:

In your conf file "hbase-env.sh": Instead of the lines that you are having :
export HBASE_OPTS="-XX:+UseConcMarkSweepGC"
Add :
-Djava.security.krb5.realm= -Djava.security.krb5.kdc=
So the line will be export HBASE_OPTS="-XX:+UseConcMarkSweepGC -Djava.security.krb5.realm= -Djava.security.krb5.kdc=" Look here for the context :Hadoop on OSX "Unable to load realm info from SCDynamicStore"

回答2:

You don't need

Configuration config = HBaseConfiguration.create();
config.addResource("/Users/apple/Documents/tools/hbase-0.94.17/conf/hbase-site.xml");

if you add this in hbase-site.xml .

and add this to your hbase-site.xml :

<property> <name>hbase.zookeeper.property.clientPort</name> <value>2181</value> </property>

回答3:

I also met this problem. I had config server name in hbase-site.xml rather than the IP, and my java client also stuck in this situation.

So I set my client system host for the server name, and I solved this case.

回答4:

At first, You check clientPort in hbase-site.xml file:

<property>
  <name>hbase.zookeeper.property.clientPort</name>
  <value>2222</value>
</property>

And in java program: You must set clientPort the same as in hbase-site.xml file:

Configuration config = HBaseConfiguration.create();
config.set("hbase.zookeeper.property.clientPort", "2222");