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

CLOB are like Files, you can read parts of it easily like this

// read the first 1024 characters
String str = myClob.getSubString(0, 1024);

and you can overwrite to it like this

// overwrite first 1024 chars with first 1024 chars in str
myClob.setString(0, str,0,1024);

I don't suggest using StringBuilder and fill it until you get an Exception, almost like adding numbers blindly until you get an overflow. Clob is like a text file and the best way to read it is using a buffer, in case you need to process it, otherwise you can stream it into a local file like this

int s = 0;
File f = new File("out.txt");
FileWriter fw new FileWriter(f);

while (s < myClob.length())
{
    fw.write(myClob.getSubString(0, 1024));
    s += 1024;
}

fw.flush();
fw.close();