用Java将CSV解析成三维HashMap

import com.opencsv.CSVReader;

import java.io.FileReader;
import java.util.HashMap;

public class CSVParser {
    public static void main(String[] args) {
        String csvFile = "path/to/csv/file.csv";
        String line;
        String cvsSplitBy = ",";

        HashMap<String, HashMap<String, HashMap<String, String>>> data = new HashMap<>();

        try (CSVReader reader = new CSVReader(new FileReader(csvFile))) {
            // Skip the header line if it exists
            reader.skip(1);

            while ((line = reader.readNext()) != null) {
                String[] fields = line.split(cvsSplitBy);

                String key1 = fields[0];
                String key2 = fields[1];
                String key3 = fields[2];
                String value = fields[3];

                // Create the nested HashMaps if they don't exist
                data.putIfAbsent(key1, new HashMap<>());
                data.get(key1).putIfAbsent(key2, new HashMap<>());
                data.get(key1).get(key2).put(key3, value);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        // Accessing the data from the HashMap
        String value = data.get("key1").get("key2").get("key3");
        System.out.println(value);
    }
}