Need Help writing CLOB file

Question

I'm trying to write a servlet that receives a file upload and
inserts the file into a CLOB in Oracle. Taking it one step at a
time. I used the O'Reilly classes for file upload to receive the
file and save it to disk. The next step of reading the file and
saving it in Oracle is where things don't seem to work.
Basically, I open a connection to Oracle. Create a new row in my
table. Select the CLOB column from the table to open the stream,
then try reading the file and writing it to the stream.
When I look at my table, I see that the row has been inserted,
but the CLOB column is null.
I'm trying to write this for eventual use in receiving
XMLdocuments into our database for processing. So if anyone has
a better way of uploading the files directly into the database
over the net, I'd appreciate it.
My code follows:
// Copyright (c) 2000 CPCC
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;
import oracle.sql.*;
import oracle.jdbc.driver.*;
import java.text.*;
import com.oreilly.servlet.multipart.*;
* A Class class.
* <P>
* @author Rivera, Maynard
public class UpLoad extends HttpServlet {
private File dir;
private String username = "mrr";
private String password = "auction";
private String thinConn
= "jdbc:oracle:thin:@192.1.100.6:1526:N";
private Connection cn = null;
Statement stmt;
private void OpenConnection (HttpServletResponse response)
throws SQLException, IOException {
try {
//Connect with the Thin Driver
DriverManager.registerDriver(new
oracle.jdbc.driver.OracleDriver ());
cn = DriverManager.getConnection (thinConn, username,
password);
cn.setAutoCommit(true);
} catch (SQLException e) {
PrintWriter out = response.getWriter();
out.println("Error connecting to Oracle");
private void ReadFile (File Dir, String FileName, String
thedate, PrintWriter out) throws IOException {
try {
String cmd = "SELECT document FROM xmldocuments WHERE
docname = '"+FileName+"' and timestamp = to_date
('"+thedate+"', 'dd-mm-yyyy hh24:mi') for update";
out.println(cmd);
ResultSet rest = stmt.executeQuery(cmd);
rest.next();
CLOB clob = ((OracleResultSet)rest).getCLOB(1);
File theFile = new File(Dir+"\\"+FileName);
FileInputStream instream = new FileInputStream(theFile);
OutputStream outstream = clob.getAsciiOutputStream();
int size = clob.getBufferSize();
byte[] buffer = new byte[size];
int length = -1;
while ((length = instream.read(buffer)) != -1)
outstream.write(buffer, 0, length);
instream.close();
outstream.close();
} catch (SQLException e) {
public void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException,
IOException {
PrintWriter out = response.getWriter();
response.setContentType("text/plain");
out.println("Upload Servlet Test");
dir = new File("c:\\myprojects");
String fileName = null;
try {
MultipartParser mp = new MultipartParser(request,
10*1024*1024);
Part part;
while ((part = mp.readNextPart()) != null) {
String name = part.getName();
if (part.isFile()) {
// it's a file part
FilePart filePart = (FilePart) part;
fileName = filePart.getFileName();
if (fileName != null) {
// the part actually contained a file
long size = filePart.writeTo(dir);
out.println("file; name=" + name + "; filename=" +
fileName +
", filePath=" + filePart.getFilePath() +
", content type=" + filePart.getContentType() +
", size=" + size);
} else {
// the field did not contain a file
out.println("file; name=" + name + "; EMPTY");
out.flush();
} catch (IOException lEx) {
// this.getServletContext().log(lEx, "error reading or
saving file");
try {
OpenConnection(response);
stmt = cn.createStatement();
SimpleDateFormat formatter = new SimpleDateFormat ("dd-MM-
yyyy HH:mm");
java.util.Date TimeStamp = new java.util.Date();
String dateString = formatter.format(TimeStamp);
String cmd = "INSERT into XMLDOCUMENTS (DOCNAME,
TIMESTAMP, DOCUMENT) VALUES ('"+fileName+"', to_date
('"+dateString+"', 'DD-MM-YYYY HH24:MI'), EMPTY_CLOB())";
ResultSet rest = stmt.executeQuery(cmd);
ReadFile(dir, fileName, dateString, out);
} catch (SQLException e) {

Answer 1

The [url=http://otn.oracle.com/sample_code/tech/xml/xmlnews/
xnewshome.html]Dynamic News sample application shows how to read
and write CLOBs. The URL is:
http://otn.oracle.com/sample_code/tech/xml/xmlnews/xnewshome.html
Regards,
-rh