Most efficient solution for reading CLOB to String, and String to CLOB in Java?

Question

I have a big CLOB (more than 32kB) that I want to read to a String, using StringBuilder. How do I do this in the most efficient way? I can not use the \"int length\" constru

Answer 1

If you really must use only standard libraries, then you just have to expand on Omar's solution a bit. (Apache's IOUtils is basically just a set of convenience methods which saves on a lot of coding)

You are already able to get the input stream through clobObject.getAsciiStream()

You just have to "manually transfer" the characters to the StringWriter:

InputStream in = clobObject.getAsciiStream();
Reader read = new InputStreamReader(in);
StringWriter write = new StringWriter();

int c = -1;
while ((c = read.read()) != -1)
{
    write.write(c);
}
write.flush();
String s = write.toString();

Bear in mind that

1. If your clob contains more character than would fit a string, this won't work.
2. Wrap the InputStreamReader and StringWriter with BufferedReader and BufferedWriter respectively for better performance.