javacsvfile-iolinebufferedwriter

Java: CSV File Easy Read/Write


I'm working on a program that requires quick access to a CSV comma-delimited spreadsheet file. So far I've been able to read from it easily using a BufferedReader. However, now I want to be able to edit the data it reads, then export it BACK to the CSV.

The spreadsheet contains names, phone numbers, email addresses, etc. And the program lists everyone's data, and when you click on them it brings up a page with more detailed information, also pulled from the CSV. On that page you can edit the data, and I want to be able to click a "Save Changes" button, then export the data back to its appropriate line in the CSV--or delete the old one, and append the new.

I'm not very familiar with using a BufferedWriter, or whatever it is I should be using.

What I started to do is create a custom class called FileIO. It contains both a BufferedReader and a BufferedWriter. So far it has a method that returns bufferedReader.readLine(), called read(). Now I want a function called write(String line).

public static class FileIO {
    BufferedReader read;
    BufferedWriter write;

    public FileIO (String file) throws MalformedURLException, IOException {
        read = new BufferedReader(new InputStreamReader (getUrl(file).openStream()));
        write = new BufferedWriter (new FileWriter (file));
    }

    public static URL getUrl (String file) throws IOException {
        return //new URL (fileServer + file).openStream()));
                FileIO.class.getResource(file);
    }

    public String read () throws IOException {
        return read.readLine();
    }

    public void write (String line) {
        String [] data = line.split("\\|");
        String firstName = data[0];

        // int lineNum = findLineThatStartsWith(firstName);
        // write.writeLine(lineNum, line);
    }
};

I'm hoping somebody has an idea as to how I can do this?


Solution

  • Rather than reinventing the wheel you could have a look at OpenCSV which supports reading and writing of CSV files. Here are examples of reading & writing