java中访问hbase有两种方式，一种是hbase自带的client，一种是通过hbase thrift
1 hbase client示例
Configuration conf = HBaseConfiguration.create();
conf.set(HConstants.ZOOKEEPER_CLIENT_PORT, "2181");
conf.set(HConstants.ZOOKEEPER_QUORUM, "zk_host");
Connection connection = ConnectionFactory.createConnection(conf);
Table profileTable = connection.getTable(TableName.valueOf("test_table"));
Result result = profileTable.get(new Get(Bytes.toBytes("test_rowkey")));
System.out.println(new String(result.getValue(Bytes.toBytes("test_cf"), Bytes.toBytes("test_column"))));
这里只需要配置zookeeper，访问的过程是先通过zookeeper找hmaster，然后通过hmaster定位到一个region server，然后访问region server，所以需要客户端到hbase所有节点（包括zookeeper、hmaster、region server）可达，即host能ping通；
2 hbase thrift示例
TTransport transport = null;
try {
transport = new TSocket(host, port, timeout);
transport.open();
TProtocol protocol = new TBinaryProtocol(transport);
THBaseService.Iface client = new THBaseService.Client(protocol);
ByteBuffer table = ByteBuffer.wrap(tableName.getBytes());
TGet get = new TGet(ByteBuffer.wrap(rowKey.getBytes()));
try {
TResult result = client.get(table, get);
return result;
} catch (Exception e) {
throw new RuntimeException(e);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
transport.close();
}
这里只需要配置hbase thrift server的ip和端口，没有任何其他依赖；单点问题可以通过加load balancer来解决；
综上，如果不需要配host，两种都可以，如果需要配host，使用thrift更简单；