Using StringBuilder to process csv files to save heap space
- by portoalet
I am reading a csv file that has about has about 50,000 lines and 1.1MiB in size (and can grow larger).
In Code1, I use String to process the csv, while in Code2 I use StringBuilder (only one thread executes the code, so no concurrency issues)
Using StringBuilder makes the code a little bit harder to read that using normal String class.
Am I prematurely optimizing things with StringBuilder in Code2 to save a bit of heap space and memory?
Code1
fr = new FileReader(file);
BufferedReader reader = new BufferedReader(fr);
String line = reader.readLine();
while ( line != null )
{
int separator = line.indexOf(',');
String symbol = line.substring(0, seperator);
int begin = separator;
separator = line.indexOf(',', begin+1);
String price = line.substring(begin+1, seperator);
// Publish this update
publisher.publishQuote(symbol, price);
// Read the next line of fake update data
line = reader.readLine();
}
Code2
fr = new FileReader(file);
StringBuilder stringBuilder = new StringBuilder(reader.readLine());
while( stringBuilder.toString() != null ) {
int separator = stringBuilder.toString().indexOf(',');
String symbol = stringBuilder.toString().substring(0, separator);
int begin = separator;
separator = stringBuilder.toString().indexOf(',', begin+1);
String price = stringBuilder.toString().substring(begin+1, separator);
publisher.publishQuote(symbol, price);
stringBuilder.replace(0, stringBuilder.length(), reader.readLine());
}
