@Override
  public Boolean exists(final byte[] key) {
    checkIsInMultiOrPipeline();
    client.exists(key);
    return client.getIntegerReply() == 1;
  }
@ Override public Boolean exists ( final byte [ ] key ) { checkIsInMultiOrPipeline ( ) ; client . exists ( key ) ; return client . getIntegerReply ( ) == 1 ; }
Test if the specified key exists. The command returns true if the key exists, otherwise false is
returned. Note that even keys set with an empty string as value will return true. Time
complexity: O(1)
@param key
@return Boolean reply, true if the key exists, otherwise false