Java Credentials.readFields示例

  public static Credentials getDTfromRemote(String nnAddr, String renewer) throws IOException {
    DataInputStream dis = null;

    try {
      StringBuffer url = new StringBuffer();
      if (renewer != null) {
        url.append(nnAddr)
            .append(GetDelegationTokenServlet.PATH_SPEC)
            .append("?")
            .append(GetDelegationTokenServlet.RENEWER)
            .append("=")
            .append(renewer);
      } else {
        url.append(nnAddr).append(GetDelegationTokenServlet.PATH_SPEC);
      }

      if (LOG.isDebugEnabled()) {
        LOG.debug("Retrieving token from: " + url);
      }

      URL remoteURL = new URL(url.toString());
      SecurityUtil.fetchServiceTicket(remoteURL);
      URLConnection connection = remoteURL.openConnection();

      InputStream in = connection.getInputStream();
      Credentials ts = new Credentials();
      dis = new DataInputStream(in);
      ts.readFields(dis);
      for (Token<?> token : ts.getAllTokens()) {
        token.setKind(HftpFileSystem.TOKEN_KIND);
        token.setService(
            new Text(
                SecurityUtil.buildDTServiceName(
                    remoteURL.toURI(), DFSConfigKeys.DFS_HTTPS_PORT_DEFAULT)));
      }
      return ts;
    } catch (Exception e) {
      throw new IOException("Unable to obtain remote token", e);
    } finally {
      if (dis != null) dis.close();
    }
  }