Tag: csv

I am still fairly new to Java and trying to learn. I am trying to create a program, in Java, that will be able to read a .CSV file that I have in my C:\ Drive and once it is read I want it to separate the data into a newer .CSV file when they are between the comments of the CSV.

For example we have the original CSV data file as follows:

 *File A
 *Name, Address, City, Country, Zip
 "John","123 Main Street","NY","USA","12345"
 "Jane","456 Main Street","NY","USA","12345"
 "Smith","789 Main Street","NY","USA","12345"
 *File B
 *Name, Address, City, Country, Zip
 "Jose","123 Main Street","NY","USA","12345"
 "Brandon","456 Main Street","NY","USA","12345"
 "Mike","789 Main Street","NY","USA","12345"
 *File C
 *Name, Address, City, Country, Zip
 "Kathy","123 Main Street","NY","USA","12345"
 "Jai","456 Main Street","NY","USA","12345"
 "Michael","789 Main Street","NY","USA","12345"

So basically I am trying to have something that will be able to read the CSV file, look for the prefix of *File, in the CSV file, and then will be able to create new files which will have everything in between. For example:

 CSV1:
 *Name, Address, City, Country, Zip
 "John","123 Main Street","NY","USA","12345"
 "Jane","456 Main Street","NY","USA","12345"
 "Smith","789 Main Street","NY","USA","12345"

 CSV2:
 *Name, Address, City, Country, Zip
 "Jose","123 Main Street","NY","USA","12345"
 "Brandon","456 Main Street","NY","USA","12345"
 "Mike","789 Main Street","NY","USA","12345"

 CSV3:
 *Name, Address, City, Country, Zip
 "Kathy","123 Main Street","NY","USA","12345"
 "Jai","456 Main Street","NY","USA","12345"
 "Michael","789 Main Street","NY","USA","12345"

I was able to find something and able to read the CSV file but just don’t know how to divide it yet. The following is the code for reading the file:

    import java.io.File;
    import java.io.FileNotFoundException;
    import java.util.Scanner;

    public class csvReader
    {
        public static void main(String[] args) throws FileNotFoundException
        {
            //Get scanner instance
            Scanner scan = new Scanner(new File("C:\\Personal_Info.csv"));

            //Set the delimiter used in file
            scanner.useDelimiter(",");

            //Get all tokens and store them in some data structure
            //I am just printing them on the screen
            while (scan.hasNext())
            {
                System.out.print(scan.next() + ",");
            }
              System.out.println("\n*************Process Complete*************");
            //Close the scanner 
            scan.close();
        }//End Main
    }//End Class

Solution:

You can grab line by line looking for particular keywords in the lines to determine what you need to do. For your current example you can use the keyword “*File” to know when to create a new file to write data to. Just remember you want to close the previous BufferedWriter if it’s currently writing to another file. Try this

  public static void main(String[] args) throws FileNotFoundException, IOException
  {
      Scanner scan = new Scanner(new File("C:\\Personal_Info.csv"));
      int fileNumber = 0;
      String csv = "CSV";
      BufferedWriter writer = null;

      while (scan.hasNextLine())
      {
          String line = scan.nextLine();
          if(line.contains("*File"))
          {
              fileNumber++;
              //check and make sure we close our previous writer
              if(writer != null)
                  writer.close();

              System.out.println("Creating a new file called: " + csv + fileNumber);
              writer = new BufferedWriter(new FileWriter("C:\\" + csv + fileNumber));
          }
          else if(writer != null)
          {
              writer.write(line + "\n");
          }
      }
      System.out.println("\n*************Process Complete*************");
      //Close the scanner 
      scan.close();
      if(writer != null)
          writer.close();
  }