Parse .txt to .csv

Question

Is it possible to create a Java program which recognizes the text in a .txt file and write it in a .csv file? If yes,how would you start with such a problem?

My .txt file is Text1 |Text 2 so I could somehow get the char "|" and split it into two cells.

Answer 1

This is very simple in Java 8:

public static void main(String[] args) throws Exception {
    final Path path = Paths.get("path", "to", "folder");
    final Path txt = path.resolve("myFile.txt");
    final Path csv = path.resolve("myFile.csv");
    try (
            final Stream<String> lines = Files.lines(txt);
            final PrintWriter pw = new PrintWriter(Files.newBufferedWriter(csv, StandardOpenOption.CREATE_NEW))) {
        lines.map((line) -> line.split("\\|")).
                map((line) -> Stream.of(line).collect(Collectors.joining(","))).
                forEach(pw::println);
    }
}

First you get your files at Path objects.
Then you open a PrintWriter to your destination Path.

Now you do some Java 8 stream processing with lambdas:

• Files.lines(txt) streams the lines from the file
• map((line) -> line.split("\\|")) splits each line to a String[] on |
• map((line) -> Stream.of(line).collect(Collectors.joining(","))) joins the individual String[] again using ,
• forEach(pw::println) writes the new lines to the destination file.

Using import static:

    try (
            final Stream<String> lines = Files.lines(txt);
            final PrintWriter pw = new PrintWriter(newBufferedWriter(csv, StandardOpenOption.CREATE_NEW))) {
        lines.map((line) -> line.split("\\|")).
                map((line) -> Stream.of(line).collect(joining(","))).
                forEach(pw::println);
    }

As Java 8 was released only yesterday here is a Java 7 solution:

public static void main(String[] args) throws Exception {
    final Path path = Paths.get("path", "to", "folder");
    final Path txt = path.resolve("myFile.txt");
    final Path csv = path.resolve("myFile.csv");
    final Charset utf8 = Charset.forName("UTF-8");
    try (
            final Scanner scanner = new Scanner(Files.newBufferedReader(txt, utf8));
            final PrintWriter pw = new PrintWriter(Files.newBufferedWriter(csv, utf8, StandardOpenOption.CREATE_NEW))) {
        while (scanner.hasNextLine()) {
            pw.println(scanner.nextLine().replace('|', ','));
        }
    }
}

Again, with import static:

    try (
            final Scanner scanner = new Scanner(newBufferedReader(txt, utf8));
            final PrintWriter pw = new PrintWriter(newBufferedWriter(csv, utf8, StandardOpenOption.CREATE_NEW))) {
        while (scanner.hasNextLine()) {
            pw.println(scanner.nextLine().replace('|', ','));
        }
    }

Answer 2

You first need to How do I create a Java string from the contents of a file?.

Then you can take advantage of How to split a string in Java and use | as the delimiter.

As the last step you can use the Joiner to create the final String and store it using How do I save a String to a text file using Java?.

Answer 3

Yes it is very much possible. Replace | by , and write it to a csv

public class NewClass {

public static void main(String[] args) throws IOException {

   String data = "one|two|three|four"+"\n"+
           "one|two|three|four";
   //Use a BufferedReader to read from actual Text file
    String csv = data.replace("|", ",");
    System.out.println(csv);

    PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("MyCSV.csv")));
    out.println(csv);
    out.close();
}
}

Output

run:
one,two,three,four
one,two,three,four
BUILD SUCCESSFUL (total time: 0 seconds)

Answer 4

Yes it is possible. To accomplish your task read about Input- and OutputStreams.

Start with a simple example. Read a line of text from a file and print it out on the console. Then do it the other way - write a line of text into a file.

The experience you get through these examples will help to accomplish your task.

Answer 5

try this may help

    public class Test {

    public static void main(String[] args) throws URISyntaxException,
            IOException {

        FileWriter writer = null;
        File file = new File("d:/sample.txt");
        Scanner scan = new Scanner(file);
        File file2 = new File("d:/CSV.csv");
        file.createNewFile();
        writer = new FileWriter(file2);

        while (scan.hasNext()) {
            String csv = scan.nextLine().replace("|", ",");
            System.out.println(csv);
            writer.append(csv);
            writer.append("\n");
            writer.flush();
        }
    }
}

sample.txt:-

  He|looked|for|a|book.

  He|picked|up|the|book.

Answer 6

Commons CSV is useful for handling CSV output in your Java code too - in particular it takes care of gotchas such as quoting, etc:

http://commons.apache.org/proper/commons-csv/

Also commons IO is really useful for simplifying reading/writing files too:

https://commons.apache.org/proper/commons-io/description.html

HTH