java Clob类型 转String

// Clob类型 转String
    public String ClobToString(Clob clob) throws SQLException, IOException {
      String reString = "";
      Reader is = clob.getCharacterStream();
      BufferedReader br = new BufferedReader(is);
      String s = br.readLine();
      StringBuffer sb = new StringBuffer();
      while (s != null) {
          sb.append(s);
          s = br.readLine();
      }
      reString = sb.toString();
      if(br!=null){
          br.close();
      }
      if(is!=null){
          is.close();
      }
      return reString;
     }

            pubKeyStr = ClobToString((Clob)app.get("pubkey"));
            priKeyStr = ClobToString((Clob)app.get("prikey"));