HBase Java 连接答案

【问题标题】：HBase Java connectionHBase Java 连接
【发布时间】：2014-09-17 09:41:11
【问题描述】：

我想通过 Java 建立与 HBase 的连接，但我遇到了问题。我通过 Ambari 在我的 CentOS 6.5 上安装了单节点 HDP 2.1。我有以下代码：

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

      final String serverFQDN = "hadoop.hortonworks";

      Configuration conf = HBaseConfiguration.create();
      conf.set("hbase.zookeeper.quorum", serverFQDN); 
      conf.set("hbase.zookeeper.property.clientPort", "2181");
      conf.set("zookeeper.znode.parent", "/hbase-unsecure");

      HBaseAdmin admin = new HBaseAdmin(conf);

      try {

          HTable table = new HTable(conf, "hb_tt2");

      } catch ( Exception ex ) {
          System.out.println("Error caught.");
          ex.printStackTrace();
      }

      System.out.println("End.");
   }
}

这是输出：

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.
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/bae/Desktop/Neue%20Bibliotheken/lib%20Hadoop/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/C:/Users/bae/Desktop/Neue%20Bibliotheken/lib%20Zookeeper/slf4j-log4j12-1.6.1.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Error caught.
java.io.IOException: Unable to determine ZooKeeper ensemble
    at org.apache.hadoop.hbase.zookeeper.ZKUtil.connect(ZKUtil.java:121)
    at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.<init>(ZooKeeperWatcher.java:165)
    at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.<init>(ZooKeeperWatcher.java:134)
    at org.apache.hadoop.hbase.client.ZooKeeperKeepAliveConnection.<init>(ZooKeeperKeepAliveConnection.java:43)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.getKeepAliveZooKeeperWatcher(ConnectionManager.java:1725)
    at org.apache.hadoop.hbase.client.ZooKeeperRegistry.isTableOnlineState(ZooKeeperRegistry.java:103)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.isTableDisabled(ConnectionManager.java:926)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.relocateRegion(ConnectionManager.java:1093)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegionInMeta(ConnectionManager.java:1374)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1128)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1111)
    at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1070)
    at org.apache.hadoop.hbase.client.HTable.finishSetup(HTable.java:347)
    at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:201)
    at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:159)
    at bt.PutExample.main(PutExample.java:41)
End.

我没有更改任何配置文件，我使用在 Hadoop 服务器上找到的 jar 文件。我是否缺少程序或服务器中的任何配置？我无法弄清楚这个错误消息的含义。

提前感谢您的帮助

【问题讨论】：

标签： java hadoop hbase apache-zookeeper hortonworks-data-platform

【解决方案1】：

尝试更改 hbase jar 的版本。有时微小的改变会有所帮助。我遇到了同样的异常，将 hbase 客户端 jars（在 pom.xml 中）从 0.98 修改为 0.98.4 有所帮助。

<version>0.98.4-hadoop2</version>

【讨论】：

【解决方案2】：

您需要将所有需要的 jar 放入 HADOOP_CLASSPATH

试试这个字符串来执行你的jar

HADOOP_CLASSPATH=`hbase classpath` hadoop jar your.jar PutExample

【讨论】：