Question

I understand how to fetch a URL text page and loop over the results

URL url = new URL(this.url);
BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
String line;
while ((line = reader.readLine()) != null) {
    ....

How would I do this to fetch an image and store it as a Blob?

Answer 1

Just get it straight as InputStream and use PreparedStatement#setBinaryStream() to store it. It’s binary data, not character data, so a Reader would only messup things, you don’t want to have that.

In a nutshell:

InputStream input = imageUrl.openStream();

// ...

statement = connection.prepareStatement("INSERT INTO image (content) VALUES (?)");
statement.setBinaryStream(1, input);
statement.executeUpdate();

A PreparedStatement is really useful. It not only saves you from SQL injections, but it also eases setting fullworthy Java objects like InputStream in a SQL statement. You can learn more about PreparedStatement at the JDBC tutorial.