Admin类的主要方法注释：
1. 创建表
/**
* Creates a new table. Synchronous operation.
*
* @param desc table descriptor for table
* @throws IllegalArgumentException if the table name is reserved
* @throws MasterNotRunningException if master is not running
* @throws org.apache.hadoop.hbase.TableExistsException if table already exists (If concurrent
* threads, the table may have been created between test-for-existence and attempt-at-creation).
* @throws IOException if a remote or network exception occurs
*/
void createTable(HTableDescriptor desc) throws IOException;
/**
* Creates a new table with the specified number of regions. The start key specified will become
* the end key of the first region of the table, and the end key specified will become the start
* key of the last region of the table (the first region has a null start key and the last region
* has a null end key). BigInteger math will be used to divide the key range specified into enough
* segments to make the required number of total regions. Synchronous operation.
*
* @param desc table descriptor for table
* @param startKey beginning of key range
* @param endKey end of key range
* @param numRegions the total number of regions to create
* @throws IllegalArgumentException if the table name is reserved
* @throws MasterNotRunningException if master is not running
* @throws org.apache.hadoop.hbase.TableExistsException if table already exists (If concurrent
* threads, the table may have been created between test-for-existence and attempt-at-creation).
* @throws IOException
*/
void createTable(HTableDescriptor desc, byte[] startKey, byte[] endKey, int numRegions)
throws IOException;
/**
* Creates a new table with an initial set of empty regions defined by the specified split keys.
* The total number of regions created will be the number of split keys plus one. Synchronous
* operation. Note : Avoid passing empty split key.
*
* @param desc table descriptor for table
* @param splitKeys array of split keys for the initial regions of the table
* @throws IllegalArgumentException if the table name is reserved, if the split keys are repeated
* and if the split key has empty byte array.
* @throws MasterNotRunningException if master is not running
* @throws org.apache.hadoop.hbase.TableExistsException if table already exists (If concurrent
* threads, the table may have been created between test-for-existence and attempt-at-creation).
* @throws IOException
*/
void createTable(final HTableDescriptor desc, byte[][] splitKeys) throws IOException;
/**
* Creates a new table but does not block and wait for it to come online. Asynchronous operation.
* To check if the table exists, use {@link #isTableAvailable} -- it is not safe to create an
* HTable instance to this table before it is available. Note : Avoid passing empty split key.
*
* @param desc table descriptor for table
* @throws IllegalArgumentException Bad table name, if the split keys are repeated and if the
* split key has empty byte array.
* @throws MasterNotRunningException if master is not running
* @throws org.apache.hadoop.hbase.TableExistsException if table already exists (If concurrent
* threads, the table may have been created between test-for-existence and attempt-at-creation).
* @throws IOException
*/
void createTableAsync(final HTableDescriptor desc, final byte[][] splitKeys) throws IOException;