Parsing a fixed-width formatted file in Java

Question

I\'ve got a file from a vendor that has 115 fixed-width fields per line. How can I parse that file into the 115 fields so I can use them in my code?

My first thought

Answer 1

Here is the plain java code to read fixedwidth file:

import java.io.File;
import java.io.FileNotFoundException;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

public class FixedWidth {

    public static void main(String[] args) throws FileNotFoundException, IOException {
        // String S1="NHJAMES TURNER M123-45-67890004224345";
        String FixedLengths = "2,15,15,1,11,10";

        List items = Arrays.asList(FixedLengths.split("\\s*,\\s*"));
        File file = new File("src/sample.txt");

        try (BufferedReader br = new BufferedReader(new FileReader(file))) {
            String line1;
            while ((line1 = br.readLine()) != null) {
                // process the line.

                int n = 0;
                String line = "";
                for (String i : items) {
                    // System.out.println("Before"+n);
                    if (i == items.get(items.size() - 1)) {
                        line = line + line1.substring(n, n + Integer.parseInt(i)).trim();
                    } else {
                        line = line + line1.substring(n, n + Integer.parseInt(i)).trim() + ",";
                    }
                    // System.out.println(
                    // S1.substring(n,n+Integer.parseInt(i)));
                    n = n + Integer.parseInt(i);
                    // System.out.println("After"+n);
                }
                System.out.println(line);
            }
        }

    }

}