Using Java, I upload an image to postgres DB size is 4000. But when I download it, the size is 8000

Question

Here is the latest code. I wanted to try something different but I am still getting the same results.

I am using postgres DB and I created a column called file with a data type bytea. The image does get uploaded to the DB (I can see it in there when I view the table's data).

I tried it with several images. The size appears to be correct when I upload it but then it doubles in size when I download it. (which breaks the image).

Any help on why this is not working is greatly appreciated.

public void uploadImage(File image, String imageName) throws SQLException {     
    try {
        conn = connectionManager.ConnectToDb();

        String sql = "INSERT INTO images (name, file) "+ "VALUES(?,?)";
        System.out.println("your image name is " + imageName);
        System.out.println("Uploaded image name is " + image);      

        PreparedStatement stmt = conn.prepareStatement(sql);
        stmt.setString(1,imageName);

        fis = new  FileInputStream(image);
        stmt.setBinaryStream(2, fis, (int) image.length());

        System.out.println("Image SIZE = " +image.length());

        stmt.execute(); 
        conn.commit();

    } catch (SQLException e) {
        System.out.println("Could not insert into DB");
        e.printStackTrace();        
    } catch (FileNotFoundException e) {
            System.out.println("Could not insert into DB");
            e.printStackTrace();
    } 
     finally {
        //close DB Objects
        try {
            fis.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        conn.close();
    }
}

public void downloadImageFromDB(String imagename) throws SQLException
{
    ConnectionManager connectionManager = new ConnectionManager();

    try {
        conn = connectionManager.ConnectToDb();
        Statement downloadImageStatement = conn.createStatement();
        downloadImageStatement.executeQuery("SELECT file FROM images WHERE name = '"+imagename+"'");
        ResultSet rs = downloadImageStatement.getResultSet();
        int i=1;
        InputStream in = null;
        int returnValue = 0;

        if(rs.next())
        {
            String len1 = rs.getString("file");
            int len = len1.length();
            byte [] b = new byte[len];
            in = rs.getBinaryStream("file");
            int index = in.read(b, 0, len);
            OutputStream outImej = new FileOutputStream("C:\\EclipseProjects\\StrutsHelloWorld\\"+imagename+".JPG");

            while (index != -1)
            {
            outImej.write(b, 0, index);
            index = in.read(b, 0, len);
            System.out.println("==========================");
            System.out.println(index);
            System.out.println(outImej);
            System.out.println("==========================");
            }
            outImej.close();
        }else
            {
            returnValue = 1;
            }

        downloadImageStatement.close();
        conn.close();

    } catch (SQLException e) {
        System.out.println("Could not get image from DB");
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } 
    finally
    {
      // close db objects.
        conn.close();
    }
    //return imgData;
}

How big is the file that is written? (`InputStream.available(...)` sometimes returns estimates) — DerMike, Oct 07 '10 at 14:37
Is the size reported by `is.available()` always twice the first size of the image, or is it always 8000? I would test this with another image to find out if the incorrect image size just happens to be twice the expected size in this case. — matt b, Oct 07 '10 at 14:39
Why are you storing an image in a `String` in the first place? A `String` is a data type for textual data, and if you store binary data in it, you've already made a mistake at that point. — Joachim Sauer, Oct 07 '10 at 14:51
Here is the latest code: I wanted to try something slightly different...but I still get the same results: — Biggs, Oct 07 '10 at 16:16
Why do you insist on using String for binary data? Again you call `rs.getString("file")` which is wrong, if you want to handle binary data. Even (and especially) if you "only" use it to get the length. — Joachim Sauer, Oct 08 '10 at 12:01

score 4 · Answer 1 · answered Oct 07 '10 at 14:37

4

You are storing your binary data into a Unicode text field. Change your file column to binary and it should work.

answered Oct 07 '10 at 14:37

Gabe

84,912
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I am using postgresql. The column file data type is bytea – Biggs Oct 07 '10 at 14:47
Biggs: Have you looked at the file generated by `fos`? How long is it? How does its contents compare to the original file? – Gabe Oct 07 '10 at 15:36

score 3 · Accepted Answer · edited May 23 '17 at 12:18

3

You don't want to use InputStream.available() to measure its size. Here's a Q&A that describes what available() actually does - in short, not much that's useful.

One (correct) way to get the actual size is to check the size of the File after you've written to it, using File.length().

edited May 23 '17 at 12:18

Community

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answered Oct 07 '10 at 14:38

Matt Ball

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score 1 · Answer 3 · answered Jan 22 '11 at 02:20

1

I used the latest version of JDBC driver and the problem was solved. I am using PostgreSQL 9.0.2 and the JDBC4 driver 9.0-801.

answered Jan 22 '11 at 02:20

Jamir

11
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Using Java, I upload an image to postgres DB size is 4000. But when I download it, the size is 8000

3 Answers3