Send blob strait to user without file creation

Question

I'm hope to find a way to take a PDF blob from my DB and send it directly to an end user without having to create a temp.pdf file.
     Connection conn = ds.getConnection();
     Statement stmt = conn.createStatement();
     ResultSet rs = stmt.executeQuery("SELECT file FROM tabe");
     if (rs.next()) {
        // retrieve PDF file
        Blob pdf = rs.getBlob("file");
        //stream to user
     }i got the blob to atleast store in a variable easy enough, but the issue is streaming it to the user.
Blob pdf = rs.getBlob("file");
// setup the streams to process blob
InputStream input = pdf.getBinaryStream();
ByteArrayOutputStream output = new ByteArrayOutputStream();
// set read buffer size
byte[] rb = new byte[1024];
int ch = 0;
// process blob
while ((ch=input.read(rb)) != -1) {
  output.write(rb, 0, ch);
// transfer to byte buffer
byte[] b = output.toByteArray();
input.close();
output.close();

Answer 1

I'll show the the code I would use:
  public static synchronized int loadBlob( File pix )
    throws NullPointerException {
    if ( pix == null ) {
      System.out.println(FILE_ERR);
      return(0);
    byte            b       = 0;
    byte[]          tempix  = new byte[50000], // change to suite
                    pixels  = null;
    int             idx     = 0,
                    size    = 0,
                    count   = 0;
    String          pixName = pix.getName(),
// Note - substitute preparedStatement as desired - just an example.
// Note, in my case the filename is the ID used.
                    sqlS    = "select"
                            + "    my_table_name.blob_thing"
                            + "  from my_table_name"
                            + " where my_table_name.blob_id = "+pixName
                            + "   for update",
                    sqlI     = "insert into my_table_name ("
                            + "    my_table_name.blob_id,"
                            + "    my_table_name.blob_thing )"
                            + "  values ("
                            + "    ?,"
                            + "    EMPTY_BLOB())";
    Statement       stmt    = null;
    PreparedStatement pstmt = null;
    FileInputStream fis     = null;
    OutputStream    os      = null;
    Blob            blob    = null;
    ResultSet       rset    = null;
    try {
* Insert initial row with empty Blob
      pstmt = conn.prepareStatement(sqlI);
      pstmt.setString(1, pixName);
      count = pstmt.executeUpdate();
* Reclaim DB row
      stmt = conn.createStatement(); // Connection aquired elsewhere.
      rset = stmt.executeQuery(sqlS);
      if ( rset.next() ) {
        blob   = rset.getBlob(1);
        os     = ((oracle.sql.BLOB)blob).getBinaryOutputStream();
        fis    = new FileInputStream( pix );
        size   = fis.read(tempix);
        pixels = new byte[size];
        for (idx = 0; idx < pixels.length; idx++)
          pixels[idx] = tempix[idx];
        os.write(pixels);
        fis.close();
        os.close();
        conn.commit();/