Question

The below is the code that I tried to print the output that comes on the console to a text file. The main idea of the code is fetch values from a csv file and print the output to a text file. Could someone let me know how this can be achieved.

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import com.csvreader.CsvReader;

public class projectInfo {
    public static void main(String[] args) {

        StringBuffer buffer = new StringBuffer();

        Connection conn;

        int count = 0;

        String sampleIddisp = null;
        String sample_name = null;
        String compound_name = null;
        String registration_date = null;

            }
            products.close();

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            System.out.println("\n Total number of records processed:" + count);

        }
    }
}

Answer 1

You never place any content in your StringBuffer buffer, so it is empty when you write it to file:

bw.write(buffer.toString());

buffer could potentially consume a large amount of memory here.

A better approach to writing the data to file would be to write the data as you read it from the database:

while (rs.next()) {
   sampleIddisp = rs.getString(1);
   ...

   bw.write(....);
}