How do I call methods using a csv file in java?

Question

I'm working on an address book program, and the last thing I'm trying to do is allow the user to specify a file that is full of commands such as: Add 'Name', Delete ' Name, Print, and so on.

All of these methods are implemented into my program already and they work when I type the commands into the console.

I've tried using a for loop that reads the commands from a file input stream, however it only ever processes the first command inside of the csv file. I've even tried adding the commands listed into a String Array first and then reading from the stream array and I get the same result.

Here is what my current code looks like that will process the first command, but nothing else.

private static void fileCommand(String file) throws IOException {
    File commandFile = new File(file);
    try {
        FileInputStream fis = new FileInputStream(commandFile);

        int content;
        while ((content = fis.read()) != -1) {
            // convert to char and display it

            StringBuilder builder = new StringBuilder();
            int ch;
            while((ch = fis.read()) != -1){
                builder.append((char)ch);
            }   
            ArrayList<String> commands = new ArrayList<String>();
            commands.add(builder.toString());
            for(int i = 0; i<commands.size();i++){
                if (commands.get(i).toUpperCase().startsWith("ADD")|| commands.get(i).toUpperCase().startsWith("DD")){
                    addBook(commands.get(i));
                }
            }
        }
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    // TODO Auto-generated method stub

}

Mattias Isegran Bergander · Accepted Answer · 2015-10-11 21:53:09Z

1

You are adding just one string with all the file's contents into the array. I'm not sure exactly what you csv-file looks like but try this instead:

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;

public class SOQuestion {

   private static void fileCommand(String file) throws IOException {
       Path pathFile = Paths.get(file);
       List<String> allLines = Files.readAllLines(pathFile, StandardCharsets.UTF_8);
       for (String line : allLines) {
           if (line.toUpperCase().startsWith("ADD")) {
               addBook(line);
           }
       }
   }

   private static void addBook(String line) {
       //Do your thing here
       System.out.println("command: "+line);
   }

   public static void main(String[] args) throws IOException {
      fileCommand("e:/test.csv"); //just for my testing, change to your stuff
   }
}

Assuming your csv-file has one command for each line and the actual command is the first part for each line.

answered Oct 11, 2015 at 21:53

Mattias Isegran Bergander

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4 Comments

Remixt Over a year ago

I will upload a screenshot of my csv file. I tried your source code and it still does the same thing. It only adds the first line.

Mattias Isegran Bergander Over a year ago

I tried it myself of course before posting, it's working and your csv-file looks like what I assume. I don't think you are actually using my source code.

Remixt Over a year ago

I copied and pasted it directly from stack overflow.

Remixt Over a year ago

I figured it out,. in my add book method I had another method call that was breaking the loop. Thanks.

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