如何将xml文件作为CLOB保存到oracle数据库中而不用在java中保存到操作系统

Question

我完成了对XML文件进行数字签名的任务，该文件位于oracle数据库表中并再次插入到数据库中。我是通过三个步骤来完成的：

1. 从数据库中获取XML文件（保存为CLOB）。
2. 数字签名。
3. 将其保存到某个目录中作为actualfile.xml。
4. 读取该文件并将其作为CLOB保存到数据库中。

问题是我想要将其保存到目录文件夹中（步骤3）。这是我正在使用的代码：

 private static void storeSignedDoc(Document doc) throws ClassNotFoundException, SQLException, FileNotFoundException {
//    public static FileOutputStream storeSignedDoc(Document doc) {
        TransformerFactory transFactory = TransformerFactory.newInstance();
        Transformer trans = null;
        FileOutputStream fileOutputStream = null;
        try {
            trans = transFactory.newTransformer();
        } catch (TransformerConfigurationException ex) {
            ex.printStackTrace();
        }
        try {
            Document signedXmlFileDoc = null;
            String destnSignedXmlFilePath = "383_ALLA_200417_001_signed.xml";
            StreamResult streamRes = new StreamResult(new File(destnSignedXmlFilePath));

//            StreamResult streamRes = new StreamResult(fileOutputStream);
            trans.transform(new DOMSource(doc), streamRes);

//            trans.transform(new DOMSource(doc), new Result(signedXmlFileDoc));
            System.out.println("fileOutputStream : " + fileOutputStream);
            ClobFile cb = new ClobFile();
            cb.insertClob();
        } catch (TransformerException ex) {
            ex.printStackTrace();
        }
        System.out.println("XML file with attached digital signature generated successfully ...");
//        return fileOutputStream;
    }//storeSignedDoc() ends here

用于检索和插入xml文件：

public InputStream getByteByClob(String query) throws ClassNotFoundException, SQLException {
        Clob clob = null;
ResultSet rs = cs.connect(query);
        while (rs.next()) {
            clob = rs.getClob(1);
        }
InputStream clobStream = clob.getAsciiStream();
return clobStream;
    }

public void insertClob() throws ClassNotFoundException, SQLException, FileNotFoundException {

String query = "---UPDATE QUERY ----";
Class.forName("oracle.jdbc.driver.OracleDriver");
        Connection con = DriverManager.getConnection("-- AS REQUIRED --");
        PreparedStatement pstmt = con.prepareStatement(query);

        File f = new File("myfile_signed.xml");
        FileReader fr = new FileReader(f);

        pstmt.setCharacterStream(1, fr, (int) f.length());
        int i = pstmt.executeUpdate();
        System.out.println(i + " records affected");

        con.close();
    }
} 

请帮我解决这个问题..