import org.apache.hadoop.crypto.key.KeyProvider.Metadata; //导入依赖的package包/类
public void execute() throws IOException {
  try {
    final List<String> keys = provider.getKeys();
    out.println("Listing keys for KeyProvider: " + provider);
    if (metadata) {
      final Metadata[] meta =
        provider.getKeysMetadata(keys.toArray(new String[keys.size()]));
      for (int i = 0; i < meta.length; ++i) {
        out.println(keys.get(i) + " : " + meta[i]);
      }
    } else {
      for (String keyName : keys) {
        out.println(keyName);
      }
    }
  } catch (IOException e) {
    out.println("Cannot list keys for KeyProvider: " + provider
        + ": " + e.toString());
    throw e;
  }
}
 

import org.apache.hadoop.crypto.key.KeyProvider.Metadata; //导入依赖的package包/类
/**
 * Create an encryption zone on directory src using the specified key.
 *
 * @param src     the path of a directory which will be the root of the
 *                encryption zone. The directory must be empty.
 * @param keyName name of a key which must be present in the configured
 *                KeyProvider.
 * @throws AccessControlException  if the caller is not the superuser.
 * @throws UnresolvedLinkException if the path can't be resolved.
 * @throws SafeModeException       if the Namenode is in safe mode.
 */
void createEncryptionZone(final String src, final String keyName,
    boolean logRetryCache) throws IOException, UnresolvedLinkException,
        SafeModeException, AccessControlException {
  try {
    Metadata metadata = FSDirEncryptionZoneOp.ensureKeyIsInitialized(dir,
        keyName, src);
    checkSuperuserPrivilege();
    FSPermissionChecker pc = getPermissionChecker();
    checkOperation(OperationCategory.WRITE);
    final HdfsFileStatus resultingStat;
    writeLock();
    try {
      checkSuperuserPrivilege();
      checkOperation(OperationCategory.WRITE);
      checkNameNodeSafeMode("Cannot create encryption zone on " + src);
      resultingStat = FSDirEncryptionZoneOp.createEncryptionZone(dir, src,
          pc, metadata.getCipher(), keyName, logRetryCache);
    } finally {
      writeUnlock();
    }

    getEditLog().logSync();
    logAuditEvent(true, "createEncryptionZone", src, null, resultingStat);
  } catch (AccessControlException e) {
    logAuditEvent(false, "createEncryptionZone", src);
    throw e;
  }
}