An example of reading a CSV file with the current csv apache commons library

Question

Can someone please provide me an example of reading a CSV file with the CSVParser Apache class? I see countless examples that use an outdated (I think) API that could not be found.

Wherever I look, I see this:

File csvData = new File("/path/to/csv"); CSVParser parser = CSVParser.parse(csvData, CSVFormat.RFC4180); for (CSVRecord csvRecord : parser) { ... } 

But nowhere can I find a jar file that has a CSVParser.parse () method that accepts these parameters. The one that takes the File object also takes the Charset parameter after it. All over the world, I see that the API describes what literally does not exist. I assume it was a pre-1.0 API, which they removed after 1.0 was released. I tried 1.0, 1.1. and 1.2 depending on my pom file, but they all have a method with the Charset parameter.

Answer 1

In the end, I just did this:

 CSVParser csvFileParser = CSVFormat.DEFAULT.parse(new FileReader(new File("/path/to/csv"))); 

There is still the thought that all official apache official docs are showing examples using a method that does not seem to exist.

Answer 2

Honestly, I could only find one reference to using CSVParser () , as you showed in your code example, and it was somewhere in some small blog. I think this is a mistake, but it would not hurt to ask the author for clarification. As I understand it, you tried the code without success, and therefore it looks like a tombstone to the possibility that this is actually an incorrect example of using the CSVParser.parser () method. I have never tried an example, so I can’t judge it anyway, I can just express my opinion.

To me personally, for what is needed to analyze a CSV file, I would create my own method, but if you insist on using Apache Commons CSVParser (which is well tested and verified by reliable code), then use the FilerReader version of the CSVParser.parser () method.

If the CSV file you are trying to parse is a standard comma separated (RFC4180), you can simply use the BufferReader as well as the String.split () method to parse the data on each line of the file, something like what is shown in this full executable java version. Pay attention to the readCSV () method:

 package csv.parser; import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.util.List; public class CSVParser { public static void main(String[] args) { try { List list = readCSV("MyCSVFile.csv"); // Display the list contents to console output. for (int i = 0; i < list.size(); i++) { System.out.println(list.get(i)); } } catch (IOException ex) { System.out.println(ex.getMessage()); } } public static List readCSV(String csvFilePath, boolean... ignoreHeader) throws FileNotFoundException, IOException { boolean useHeader = true; if (ignoreHeader.length != 0) { useHeader = ignoreHeader[0]; } List list = new ArrayList<>(); BufferedReader br = new BufferedReader(new FileReader(csvFilePath)); // Reading header. Ignoring the contents if false was supplied to ingnoreHeader. String line = br.readLine(); String[] fieldTitles = {}; if (useHeader) { fieldTitles = line.split(","); } while ((line = br.readLine()) != null) { if (!line.trim().isEmpty()) { String[] fields = line.split(","); String strg = ""; for (int i = 0; i < fields.length; i++) { if (useHeader) { if (strg.equals("")) { strg = fieldTitles[i] + ": " + fields[i]; } else { strg+= " | " + fieldTitles[i] + ": " + fields[i]; } } else { if (strg.equals("")) { strg = "Field " + (i+1) + ": " + fields[i]; } else { strg+= " | Field " + (i+1) + ": " + fields[i]; } } } list.add(strg); } } br.close(); return list; } } 

Format the incoming string data, as you see, within the readCSV () method. A simple CSV text file named MyCSVFile.csv will contain the following:

 NAME,CAPITAL,CURRENCY India,New Delhi,INR USA,Washington,USD England,London,GBP Japan,Tokyo,JPY 

If the first line of the file, of course, will be the data header.